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Products => Other Equipment & Products => Topic started by: scatterandfocus on September 02, 2019, 03:54:24 am

Title: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 02, 2019, 03:54:24 am
Years ago I had a Hakko 936 ESD that worked great for my needs.  I soldered many audio cables, jacks, pots, and lots of other miscellaneous joints  with it and only a couple of hakko chisel tips over the years.  I think I paid around $100 back then.  Now I see that the 936 is discontinued, replaced by the FX888, replaced by the FX888D.  I can't say that I am a fan of the casing or digital controls.  The case reminds me of an anti-homeless bench morphed with a toddler's toy.  And what was wrong with the pot?  Why the digital interface?

Anyway, does it work just as well as the old 936 did?  Is it serviceable?  Anything else worth looking at in this price range?  I only have a crappo cheapy pencil at the moment that really needs to be thrown out.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: james_s on September 02, 2019, 04:30:57 am
I really wish they'd bring back the classic 936. I'm not a fan of the digital interface on the 888d either and I agree it's hideously ugly although it's a tool so whatever. I've used one a few times and aside from the annoying interface it does work as well as a 936.

You might also look at Pace and if budget allows Metcal is very good. Another is Edsyn, I have one of their older Loner models I bought used probably 20 years ago and it has served me well. Pretty sure they still make them very similar.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: amyk on September 02, 2019, 05:08:19 am
You can get a 936 clone, some use thermocouple heater/sensor assemblies but others can use the genuine thermistor-based Hakko heater/sensors too. They still have the simple analog controller.

If you're feeling really adventurous, you can buy a genuine Hakko handle and build your own controller. There's no shortage of openly available information out there.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 02, 2019, 05:21:02 am
No, the Hakko FX-888 is no longer the best option.

The FX-951 is, and if you don't want to spend that much on it, you can get one of the Chinese T12 soldering stations (which work reasonably well - much better than the FX-888).

I paid about $60 on my T12 station and it outperforms the FX-888 in every way.

There's also an older opensource project, called unisolder. There's a chance the Chinese stations are based on that. With the unisolder you have to build your own board/enclosure and buy a commercial iron, like a Hakko or JBC.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 02, 2019, 07:34:18 am
The Pace ADS200 is a US made 120W station that came out last year, it's primarily designed for manufacturing but is a great price so makes it viable option as a prosumer model.

You won't even want to consider any Chinese made Hakko clones after using this station. It's far superior to Hakko FX-951 (where the T12 tips series come from) in power, heating speed, materials, interface, display, features, iron, price, tip price in other words EVERYTHING.

The version of the Pace ADS200 you want is the "instant setback" version. It's about ~$220 (with eevblog discount (https://www.eevblog.com/forum/testgear/eevblog-members-discount-at-tequipment/)) from tequipment.net who should do free shipping. You will also need to order some tips.

Don't get fooled by what the ADS200 looks like, it's a powerful high end station and has a very easy to use interface (unlike the Hakko FX-888D and FX-951 digital interfaces) even easier to use than a T12 clone and WAY safer. It uses a special handpiece made of aluminum and the station and stand are all metal construction nothing matches it for a couple of hundred bucks. It would suit you perfectly if you just came from the Hakko 936 which was a great station in itself.

(https://www.eevblog.com/forum/reviews/new-pace-ads200-production-soldering-station/?action=dlattach;attach=480029;image)

(https://www.eevblog.com/forum/reviews/new-pace-ads200-production-soldering-station/?action=dlattach;attach=507950;image)
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: MosherIV on September 02, 2019, 08:52:31 pm
Hi

Soldering iron is a personal preference. People have huge debates here about which is best.

If you like the old Hako 936, then as some others suggested look at some of the clones.
Look at bigclive reviews
https://m.youtube.com/watch?v=aIab66EgfHM (https://m.youtube.com/watch?v=aIab66EgfHM)
However, that technology is old, thermal coupling and the temp control loop is not as good as the more modern T12 cartridge tips that Hakko do.

I am beginning to think that Shock is an agent for Pace or has shares in them  ;)

My peronal preference is for Metcal. The old SP200 can be picked up cheap used. If you are lucky you might get a MX5000.

Others say they love the T1000

Another option is the Bakon 950d, a Hakko T12 based iron, which others have recommended.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: james_s on September 02, 2019, 09:49:42 pm
I wouldn't consider a clone, too much variability, you never know what you're getting and a lot of them are junk.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 03, 2019, 12:06:55 am
In the US, I think 888 is one of the best options. It's about $100.00, here. Maybe less.

The UI is clunky, out of the box. But you can set up to 5 presets. Once I got used to using presets, I prefer it for consistency. I have an analog 888 from years back, which I haven't used in quite a bit, now. But I do some production soldering. I also cheat, having hacked the interface with 5 push buttons, one for each preset.

Other than the digital interface, the main difference of the 888 vs a 936 is a significant boost in power and a better iron stand. Maybe one of the best iron stands ever made.

Been using the 888 for over a decade, and the only part that has needed replacement is the tip. I've replaced one or two in that time, and probably gone through 5 lbs of solderwire... which is quite a lot of solder for SMD parts.

Quote
I paid about $60 on my T12 station and it outperforms the FX-888 in every way.
IMO, Hakko 888 > any T12 clone. I have two T12 clones. Forced myself to use T12, solely, for 2 months just to make sure I got used to it and didn't short change it. (Soldered probably around 1K-2K components in that timeframe). Compared them side to side, extensively. Did actual testing with temp probes. T12 clones do not perform even as well as the 888 in the way that matters... i.e., the T12 clones had to be set to a higher set temp to solder the same things, noticeable after months of use and confirmed with scientific testing with temperature tester. There was more thermal drop in the T12 clones, using the same tips; the T12 stations had to be set higher and had to be turned up higher and/or more frequently when encountering heavy joints, using the equivalent tips. Despite much faster warm up from cold. Marketing hype and placebo effect, IMO; oooh, cartridge! They are pretty good, and better in a couple ways (which don't matter for 99% of people 99% of the time, IMO). In another country, where the price difference is much greater, I might actually recommend a T12 clone for a hobbyist. In the US, there's almost no reason to not get a genuine 888 other than maybe the UI. Cartridge vs T18... not a real improvement for most hobbyists, IMO, or even a pro like me. Not until you get into 100+watt range and/or production soldering (one joint after the other, nonstop) of huge thermal mass stuff.

Real 951? I can't say an 888 is better than a 951. I have never used a 951.

Edit: I did such extensive testing partly cuz of STJ saying multiple times T12 clone >> 888 for 2 months straight. I guarantee he has never used an 888 and probably doesn't solder very much. He posted a pic, and it showed he was still using the fold out tin stand for the clone, lol. One of the clones I bought was the same exact one he raved about, just to see how cool these magic beans were. I'll say for the money, both the T12 clones I bought and used work really well. They can do w/e I need. That said, after my trial period, I haven't used either one in almost a year, now. I prefer the 888 for ergos and better performance. I went a bit overboard, at that time, too. I think I must have bought over a dozen different T12 tips and probably more than half are still unopened. :) When you do production soldering one or two (long and boring) days a week, you might spend a bit just to change things up!

When it comes to the "old, obsolete stations," 888 != 936 and 936 != any generic, sub $40.00 Hakko compatible iron.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 03, 2019, 12:32:25 am
I am beginning to think that Shock is an agent for Pace or has shares in them  ;)

Hah, in that case I should get double shares in Fluke :). I used to be an old Weller (notice the iron in my avatar) and Hakko guy and used Pace among other brands years ago at work. Am partial to robust tools but also a fan of analog and 7 segment displays.

I prefer Metcal over JBC for the same reasons Metcal users do, I just prefer temp adjustable stations and expensive tip prices give me heart palpitations. When the ADS200 came out I did a little fist pump that the soldering gods had listened.

But anyway if noone talks about the virtues of the station it will be years before people find out, think of all the lives I can save from buying a Hakko FX-951 or T12 clones.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: bdunham7 on September 03, 2019, 12:44:23 am
I have the analog FX-888 and the only iron I've personally owned that came close was an old Antex and that is probably more fond memories than reality.  I can't compare it to systems I haven't tried, but I have tried 'clone' tips and they just sucked compared to the OE Hakko.  The performance of the tips are definitely the best part of the deal with Hakko, and the feel of the handle and cord are right up there as well.  I haven't tried a clone heating element so no idea there...  There is a raft of counterfeit Hakko stuff out there in addition to the clones and unless you are absolutely sure that a comparison was done against a genuine product, it probably isn't a review worth considering.   

So, for $100 my money would still go to the FX-888.   At $200+ I might start looking at other options like the Pace or FX-951, but keep in mind that the tips on the FX-888 are $6-8 apiece while others may be a lot more.  An FX-888 with 5 good tips is a pretty good setup.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 03, 2019, 01:59:20 am
So, for $100 my money would still go to the FX-888.   At $200+ I might start looking at other options like the Pace or FX-951, but keep in mind that the tips on the FX-888 are $6-8 apiece while others may be a lot more.  An FX-888 with 5 good tips is a pretty good setup.

Yeah there is no doubt the Hakko 936 and 888 are great stations. When the 936 was being discontinued for $50 and the 888D was on sale for around $60 dollars they were absolute bargains.

What is not so obvious is there is only a 5W difference in power between the Hakko FX-888D and the Hakko FX-951 handpieces. The Hakko FX-951's T15 (aka T12) series tips while faster heating have less overall mass. So that means double the price but you do not get double the performance. Then the tips are 4-7 times more expensive, plus extra sleeves etc, you get the idea.

Before you seriously consider the Hakko FX-951 check what I wrote about the Pace station (https://www.eevblog.com/forum/reviews/hakko-still-the-best-option-for-a-hobbyist-soldering-station/msg2659812/#msg2659812) a few posts back. The Pace station is considerably more powerful plus tweezer compatible and only $11 for the standard cartridges and $12.60 for the ultra tips.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 03, 2019, 02:05:45 am
^ Shock talks some sense.

But here's a tip. If you do end up getting a 951 or a T12 clone, be sure to check prices for T15 tips. Apparently, they are the exact same thing, but in some of online price comparisons that I have done, the Hakko T15 version is $15.00 vs $30.00+ for same tip listed as T12. (Same tips in Hakko T18, $5-8.00 all day. Other than the spatula tip and TWO lengths of bent conical, T18 has slighty better, slightly more comprehensive variety of tips for general SMD soldering, IMO).

Quote
the 888D was on sale for around $60 dollars they were absolute bargains.
In the US, you can buy the 888 for under $100 for the last 5 years, or so. Two of mine, I bought for $80.00 a piece, new.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: blueskull on September 03, 2019, 02:35:54 am
OP, I have a 888D lying around. I'm moving back to China and I can't bring it with me due to the weight and voltage.

PM me if you want to have it. Asking for $30+shipping.

Used for only a few times. With one conical tip.

Ship from North Carolina.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 03, 2019, 05:40:31 am
Thanks blueskull.  I sent you a pm.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Mr. Scram on September 03, 2019, 06:20:59 am
That's a good deal!
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 03, 2019, 12:49:44 pm
@KL27x, I don't know who SJT is or which T12 station you've tested, or even if the performance varies that much between them, but mine is so much better than the FX-888, it's unbelievable.

I had the FX-888 about 7 years and after getting the T12 station, I "retired" it to my secondary soldering space.

My findings are the opposite of yours, so I'm inclined to believe you got a dud.

1) The T12 one holds the temperature better, with the same size tip.
2) It also gets to temperature in just a couple of seconds, compared to the FX-888 which takes 30 seconds+.
3) Contrary to your findings, I can solder better at lower temperatures than with the FX-888.

In fact, the T12 is so good, I use it for soldering SMA connectors too, while when I was using the FX-888 as my main station, I had to switch to a soldering gun for that.

That said, I did have a surprise when I bought it: it didn't work.

The MCU was not properly soldered but that was easily fixable (took me a while to find the fault tho).

Anyway, yours is not the only complain I read (I got to read quite a few when trying to figure out why mine wasn't working), so I guess it's a gamble. The lack of QA and the uncertainty on weather you're getting the same product from one order to the next, is clearly a point against these soldering stations.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: GreyWoolfe on September 03, 2019, 02:50:20 pm
I am with jadew.  I had a 936 for about 7 years myself.  Much done with it.  Went to a 951 and didn't look back.  HUGE difference between them.  I now also have a Metcal MX-500.  I will agree that the Pace is a solid value.  However, I like not worrying about temp settings with the Metcal.  Plug a tip and go and you can solder 2 bumpers together. >:D
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Tarloth on September 03, 2019, 06:24:23 pm
I did have an original Japanese 936 for a lot of years, wonderful solder station, nothing to regret at this time. I bought some years ago the 888d, really better than 936, not a huge difference, but definitively better. I bought a used Japanese 951 base station to an user of this forum (Thanks again! ^) and buy in Europe the original handle with original tips. WORKS A LOT BETTER THAN 888d or 936! If you ask me if that justify the money difference? NOT FOR A CASUAL use or one day a week use. And the $30 deal it's imbatible! But if you solder more than 3 or 4 hours a day definitively I go for the option of a 951 or a new Metcal without any doubt. I test in a showroom the Pace solder station and really not found anything that impress me. Perhaps the components to solder selected by the seller not where the best option, but all connectors that I did solder with the Pace at showroom took the same time and effort than with the 951 and most the same  time than the 888D. I can only tested in one power bar and the time perhaps was a bit less (a fraction of second) than something equivalent in the 951, but I not sure.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Tarloth on September 03, 2019, 06:36:51 pm
I did pay for the T15 tips at www.batterfly.com (http://www.batterfly.com) 14 Euros each, but buy some geometry "that are not frequently to use" in ebay (countefeit for sure) for less than 5 dollars and works reasonably ok.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 03, 2019, 07:55:20 pm
Quote
My findings are the opposite of yours, so I'm inclined to believe you got a dud.

1) The T12 one holds the temperature better, with the same size tip.
2) It also gets to temperature in just a couple of seconds, compared to the FX-888 which takes 30 seconds+.
3) Contrary to your findings, I can solder better at lower temperatures than with the FX-888.

I have the idea that your 888 is defective or fake. Or maybe you used a 936 or clone? Or maybe you never actually timed it and are going by feel/memory. It take exactly 17-18 seconds for an 888 to get fully to my typical soldering temp with the some of the heaviest tips that you can buy. Maybe 20 seconds if you solder with leadfree and at a high temp.

I did not "get a dud." My T12 clones all work perfectly fine. Yes, the 24.5V versions warm up in about 9-10 seconds, depending on the tip. But the T12 tips are around half the mass. I gave one away, and the guy loves it. Well, compared to Weller micro pencil, I'm sure this is a major improvement in thermal performance, esp with some of the tips I gave.

I had the opportunity to do a lot of production soldering of the same exact things I do with the 888, over a fairly long time period of 2 full months. T12 clones were slightly worse, although they had a couple advantages. I did not use genuine Hakko T12 tips. And I DID NOT MAX out either iron, so I don't know which iron can solder a larger tire lug when you peg the iron to max temp. If that's how you rate an iron, that's different from what I want in an iron. If you rate an iron by how big a joint is can make, then a blow torch is the best iron and it's only $20.00.

I have never even turned any of my irons all the way to max temp, before. The highest I've ever set my 888 is 380C, and only for a matter of seconds to solder to 18650 cells, or the like. For someone else, max might be your default setting; watching some Louis Rossman videos, I get impression that he leaves his at max all the time; actually seen him looking for the key to demonstrate how to change temp of his 951, and it was set and locked to 480C. And yeah, he has bragged about killing a tip a month, barely soldering anything at all compared to a production solderer. A production solderer solders in a day what a repair guy does in a month; not that I have to solder multilayer mobos with a micro pencil-dick tip; different needs, for sure.

That would be nice if a T12 iron could solder a significantly larger tire lug (I don't believe it*), but I want an iron that solders the 99% of my normal soldering the best. Lowest temp, longest wet time, least cleaning of the tip, and minimal need to make adjustments when encountering more demanding joints. And I'm not going to say that it's not even close. It is. But the 888 comes out on top and is noticeably better. Of all the supposed advantages of putting the sensor and heater "right inside the tip," this is the one that many people heap the most praise upon... and it is worse (in the clone with non-Hakko tips, anyhow).

Temperature probe test from last year, IIRC.
https://www.eevblog.com/forum/reviews/t12-clone-vs-888-practical-test-results/msg1466474/#msg1466474 (https://www.eevblog.com/forum/reviews/t12-clone-vs-888-practical-test-results/msg1466474/#msg1466474)
*The test demonstrates that when outputting the same amount of wattage through the tip onto a joint, the T12 clones must be set to a higher set temp and suffers greater "thermal drop" in its control circuit and/or firmware. When NOT pressed against this sink and keeping it at the same temp as the 888, the T12 clones will return back up to their higher set temps. Add fact that T18 tip is twice the mass, and they all go roughly to same max temp of more or less 480C with roughly similar wattage rating, if/when push comes to shove, I will not be inclined to think the T12 clones can do much than the 888 cannot. But I don't know. Maybe the tables turn at much higher outputs and/or maybe a T12 wattage is actually much higher than an 888 even though the rating is similar (Maybe the 888 puts a significant amount of its 65-70W into the handle/air vs the 24V T12 clones 85ish(?) watts. (I'm giving T12 clone higher rating than 951's 75W rating, due to half a volt higher voltage and use of FET vs TRIAC).

You can get a great first impression, no doubt swayed by the fast warm up time. So backing up your impression with numbers is good. But you are off to a bad start saying your 888 takes 30 seconds to get to temp (unless you solder at 400C?). It definitely takes about twice as long, but that greater mass in the tip is working FOR you once it reaches temp. I used a station that took an actual 30 seconds to warm up (which I say because I actually timed it) - a cheap 45-50W Velleman re-badge. It still works fine, and the guy I gave it to still uses it to this day, 5 years later. But he works in finance. When I used it, something broke every few years.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 04, 2019, 12:56:25 am
I go for the option of a 951 or a new Metcal without any doubt. I test in a showroom the Pace solder station and really not found anything that impress me.

What and where was the show room you did this at? I didn't know they have show rooms setup to demonstrate the Pace ADS200. And nothing impressed you? I mean there are some glaring differences in the stations. Like when you switch it on, change the temp, select a preset, swap tips, the mysterious absence of the control card that blocks the user interface, what do you think about entering temp offsets?

The differences in soldering between the two are more noticeable if you are actually soldering. Doing a few odd joints at say 350C will not highlight appreciable differences as clearly as soldering repetitively or doing challenging thermal joints. That is more likely to factor in the Pace ADS200s power and recovery speed, plus the extra mass over the heater on the ultra performance series of tips.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: AngusBeef on September 04, 2019, 02:00:33 am
Honestly, I've had a Hakko 703B rework station I picked up on Ebay for 100 dollars with some chinese clone irons and it works amazingly well. The desoldering tool is literally the best thing I ever found as a hobbyist, although I imagine some of the old guys shake their heads and would tell me to just use braid and an iron

Sent from my SM-T820 using Tapatalk

Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 04, 2019, 05:33:09 am
There was also the Hakko 701 unfortunately the desoldering iron tips are fairly obsecure these days to find. The 703B has the better desoldering iron from the looks of it. I doubt you are going to get people argue against the benefits of a desoldering iron, if you are doing a large amount of desoldering it's a huge time saver.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Tarloth on September 04, 2019, 07:13:04 am
Quote
What and where was the show room you did this at?

Buenos Aires, Argentina, at one importer that begun to sell this stations and have two units to test it for possible customers.

Quote
I didn't know they have show rooms setup to demonstrate the Pace ADS200.

However there are :-)

Quote
And nothing impressed you?

Really not. They provide practice PCB with a lot of dummy components to test with a very different thermal mass and I not notice any advantage over other solder stations.

Quote
I mean there are some glaring differences in the stations.

Not for me, if I did noticed something I honestly I would remark it. I'm not a Hakko seller, and assume that you aren't a Pace seller, I assume that all the reviews are honest and every person has their personal tastes.


Quote
Like when you switch it on, change the temp, select a preset, swap tips, the mysterious absence of the control card that blocks the user interface, what do you think about entering temp offsets?

A solder station it's not an Android tablet with fancy software, it's a tool to solder at any adjust. I still prefer a good dial to set the temperature over any fancy interface. I set the work temperature one's per job, sometimes I work several day's with the same setting. Both stations permit change the temperature,  in my hakkos I set the presets when I use the first time and never touch temp again. Simply change the preset. One button, that's it. In the Pace I can change the temperature easiest than Hakko, but the presets are the same to change or worst and really I use the presets all the time, never I need to change the working temperature in 2 degrees, If one preset it's not ok I take the next one.

I considered that a good solder stations have the sufficient thermal control to set it to any temperature (not too high) an solder anything. In a clone I need to continuously change the temperature to solder different components. In my Hakkos or in the Pace that I test I set one temp and solder almost all of the components without compromise. Both stations seems to me equivalent without nothing to remark between them.

I not use the control card, 888d not have one and in the 951 I put a tape inside, but when I did receive the station use it without problem. A friend use it to not change by error the settings and in his words it's util. Every person with his preferences.

I test my tips against a temp checker (a Hakko clone) when I remember it or I am very bore with the Job (it's an excuse to stop working). Never notice yet any important difference. In the show room have an original Hakko temp checker (irony?) but I not did change any temp offset and not use the interface to do that. I only did need to compensate some tips in the old times when the geometry of the tip was very odd and they was passive tips. I not use any T12/15 tip that need to be compensated yet, but probably I would not compensate it for normal use neither. 

Quote
The differences in soldering between the two are more noticeable if you are actually soldering.
I did solder with the station for an hour or more. I didn't think that with more hours of use I notice any important. I did solder a lot of different tiny SMD and also a lot of high thermal mass components, all perfect, the same in any good solder station, nothing supreme or peculiar.

Quote
Doing a few odd joints at say 350C will not highlight appreciable differences as clearly as soldering repetitively or doing challenging thermal joints. That is more likely to factor in the Pace ADS200s power and recovery speed, plus the extra mass over the heater on the ultra performance series of tips.

I did solder one really defiant power bus, same response in my Hakko for similar jobs. Same recovering and perhaps in Pace worst tip to PCB transfer but nothing to blame to Pace itself, I have in my hakko biggest tip that I did have in the Pace demo and then notice better response in my Hakko than in the PCB but not using the same tip. If really the solder station did transfer more energy than Hakko to the PCB I didn't notice it.

In general terms I prefer my hakko essentially because I have been using them for years (actually in the 951 were months ) but Pace seemed like a good solder station, it honors the brand, but nothing I have tried seemed really better than in Hakko or others brands. A good product indeed but nothing really relevant or impressive to me.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 04, 2019, 02:05:46 pm
@KL27x,

My FX-888 station was bought new, from an authorized distributor. It was a bit over $200, since I live in the EU.

I timed it and it takes about 22-23 seconds for heating to stop, which means the heating element has gotten to temp (330 C), not the tip. The T12 clone takes less than 10 seconds, like you also noted, and the element is fused with the tip (like you well know), so the lag is much, much smaller and thermal regulation is unsurprisingly better.

I would like to point out that the T12 clone you used in your tests looks nothing like mine, so like I said earlier, maybe you just got a shitty one. It's not unheard of for chinese clones to be absolute garbage. How are you so sure that your clones are perfect? Considering your test results, I'd say you just proved they're not.

There's a saying in my language: "If two people are telling you you're drunk, better go to sleep.". Considering the majority of people who tried them are absolutely excited about those T12 clones, is there any chance that YOU did something wrong, and not that everyone else is stupid and doesn't know how to set their temperatures properly?
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Mr. Scram on September 04, 2019, 03:52:28 pm
@KL27x,

My FX-888 station was bought new, from an authorized distributor. It was a bit over $200, since I live in the EU.

I timed it and it takes about 22-23 seconds for heating to stop, which means the heating element has gotten to temp (330 C), not the tip. The T12 clone takes less than 10 seconds, like you also noted, and the element is fused with the tip (like you well know), so the lag is much, much smaller and thermal regulation is unsurprisingly better.

I would like to point out that the T12 clone you used in your tests looks nothing like mine, so like I said earlier, maybe you just got a shitty one. It's not unheard of for chinese clones to be absolute garbage. How are you so sure that your clones are perfect? Considering your test results, I'd say you just proved they're not.

There's a saying in my language: "If two people are telling you you're drunk, better go to sleep.". Considering the majority of people who tried them are absolutely excited about those T12 clones, is there any chance that YOU did something wrong, and not that everyone else is stupid and doesn't know how to set their temperatures properly?
The results with the T12 clones seem to vary a lot. Some people have good results while others are total shit. Some people have multiple units with either result. I've been bitten by a well regarded cheap soldering station before and regretted not spending a bit more on a decent and proven station.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 04, 2019, 05:47:56 pm
The results with the T12 clones seem to vary a lot. Some people have good results while others are total shit. Some people have multiple units with either result. I've been bitten by a well regarded cheap soldering station before and regretted not spending a bit more on a decent and proven station.

Yeah, I mentioned that too in a previous post. I think this is an inherent problem with things that are built to BOM price + a little extra. There's no room for QA and no room for extra care, so you always get a rushed job (of an otherwise good design - maybe).
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 05, 2019, 09:47:55 pm
Quote
I would like to point out that the T12 clone you used in your tests looks nothing like mine, so like I said earlier, maybe you just got a shitty one. It's not unheard of for chinese clones to be absolute garbage. How are you so sure that your clones are perfect? Considering your test results, I'd say you just proved they're not.

There's a saying in my language: "If two people are telling you you're drunk, better go to sleep.". Considering the majority of people who tried them are absolutely excited about those T12 clones, is there any chance that YOU did something wrong, and not that everyone else is stupid and doesn't know how to set their temperatures properly?
You make very good points. I don't know all the clones, and I have never even see a real 951.

But let's say there was a guy stating that any T12 clone is better than any iron using obsolete technology by miles and it's not even close. And he used a particular clone called a Bakon. I bought the same one for this reason. I also bought one with a 24.5V PSU, since the Bakon is less; I think it's 19.5V.

Re 888, if I hadn't been on for the last 40 hours, I would test it right now to w/e temp you think is right for soldering. I still have a Bakon and one of the 24.5V clones, but since you suspect they're not good ones, maybe you can share what is your model you are so pleased with?

Quote
the element is fused with the tip (like you well know), so the lag is much, much smaller and thermal regulation is unsurprisingly better.
This part, though, I could debate is faulty reasoning, to jump to this conclusion.
Quote
I timed it and it takes about 22-23 seconds for heating to stop, which means the heating element has gotten to temp (330 C), not the tip.
I'm sorry, but you may have decided which one is better based on incorrect assumptions. What you imply, here, is revealing.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: rsjsouza on September 06, 2019, 02:33:59 am
I really like my old FX888 (not D) bought 7~8 years ago. Although the enclosure and colors are a bit weird, it is really easy to find it among all the mess that is my desk.  :-DD

I also use other Hakko stations and Metcal. I mention my experiences at:
https://www.element14.com/community/thread/65381/l/solder-station-selection?displayFullThread=true#247847 (https://www.element14.com/community/thread/65381/l/solder-station-selection?displayFullThread=true#247847)

https://forum.allaboutcircuits.com/threads/what-soldering-station-up-to-300-should-i-choose-list-attached.162559/#post-1425339 (https://forum.allaboutcircuits.com/threads/what-soldering-station-up-to-300-should-i-choose-list-attached.162559/#post-1425339)
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: james_s on September 06, 2019, 03:34:23 am
I really can't figure out what Hakko was going for with the color scheme. I don't buy my tools based on cosmetic appeal, but just the same I look at their current product line and am reminded of Fisher Price or Lego toys, it certainly does not scream "professional tool".
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Bud on September 06, 2019, 03:44:10 am
My bet is that was what their CEO liked.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: blueskull on September 06, 2019, 04:14:10 am
I think this is an inherent problem with things that are built to BOM price + a little extra. There's no room for QA and no room for extra care, so you always get a rushed job (of an otherwise good design - maybe).

Depending on who's doing the QA and how much they are paid.

I've got bad QA from Keysight, repetitively, and so far only a very few items came without problems at all.

FFS their uber expensive PXI system came with a missing screw (in my case, M9111A SMU card).

Or scopes (a pair of M9243A) with bad active probe interfaces?

Or how about a CAT IV rated meter (U1461A) with faulty input MUX that reads 0V when input is hot?

Or how about logic probe grabbers (54620) came with cracked plastic parts? Not one, but virtually all the 20 pins.

To their credit, KS does offer exceptional services. No questions asked, replacement shipped or refunded right away even before I shipped the bad units.

I can't say the same for Tek. Tek calibration center shipped with my Fluke 289 (for calibration) a pair of leaky batteries and refused to pay for the corrosion repair???
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 06, 2019, 04:48:32 am
Unfortunately that $30 fx-888d fell through.

So I have been looking over the recommended brands/models in this thread and elsewhere.  Trying not to get too far away from a $100 price point (remember, hobbyist), the fx-888d seems like it would be ok after setting the presets.  But if I need to dial up/down the temp a bit from the preset temp, the menu diving must be engaged.  And watching youtube videos of using the menu, I wouldn't like using it.  I would much rather just have a temp knob and avoid all that mess.  I never heard of Edsyn until this thread, and the 951sx looks well worth considering.  It has a good old temp knob, no digital controls.  The heater is rated at 95w vs. 65w for the fx-888d.  And it doesn't look like a toddler's toy.  And I don't care that much about the color scheme, but the overall design just seems anti-user to me.  At least the Edsyn tried to be space saving, which shows consideration in the design.  For just a little more money than the Hakko, I think the Edsyn would be the best option for me.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: blueskull on September 06, 2019, 04:58:04 am
Unfortunately that $30 fx-888d fell through.

Unfortunately I got it lost, maybe gifted or sold it at some point.

If you are looking for one notch up, ADS200 or a used Metcal are both good options.

I got my first Metcal for only $220 from a French forum member.

It's such a power house that I still use it despite having two $1200 JBC stations (HDE and NASE).
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 06, 2019, 05:03:14 am
Unfortunately that $30 fx-888d fell through.

Unfortunately I got it lost, maybe gifted or sold it at some point.

If you are looking for one notch up, ADS200 or a used Metcal are both good options.

I got my first Metcal for only $220 from a French forum member.

It's such a power house that I still use it despite having two $1200 JBC stations (HDE and NASE).

As I said in email, it's really no problem.  And in a way I'm glad that you didn't find it, because after taking a closer look at the fx-888d menu in use, I think that I wouldn't like using it.  It would annoy me.  I just want a temp knob, really.  But thanks all the same for the sentiment and looking for it.

When I had the Hakko 936, I just got used to rolling down the temp knob when I put the iron in the stand, if I were using it for any extended period of time.  It's just a small habit to get into.  And I could very well do the same with the Edsyn.

Also, I noticed some commenters in Dave's comparison video of low cost Hakko and Weller stations mentioning that the fx-888d gives slow updates of the temp readout.  That sort of thing causes me to put not much merit in digital temp displays.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 06, 2019, 06:24:39 am
I'm not a fan of the Hakko's FX-888 design either.

Regarding Metcal, yeah, I know a couple of people that have Metcal stations and they absolutely love them. Apparently there's another company making the exact same thing, called Thermaltronics - heard good things about this one too and they're supposed to be cheaper.

If I was getting my first station today and I didn't want to take any risks, I'd probably get either an FX-951 or a used Metcal, like it was suggested.

Quote
the element is fused with the tip (like you well know), so the lag is much, much smaller and thermal regulation is unsurprisingly better.
This part, though, I could debate is faulty reasoning, to jump to this conclusion.

What's faulty in that line of reasoning?

Quote
I timed it and it takes about 22-23 seconds for heating to stop, which means the heating element has gotten to temp (330 C), not the tip.
I'm sorry, but you may have decided which one is better based on incorrect assumptions. What you imply, here, is revealing.

There are no assumptions in that statement. Care to point them out?

I decided which one is better based on which one performs better. I too am soldering stuff and I can tell very well which one does better. Despite agreeing to the idea that your T12 station might not be as good as mine, and that's why we're getting different results, you still seem to imply that the most likely reason why I think the T12 station is better is because I'm stupid.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 06, 2019, 06:15:55 pm
Quote
What's faulty in that line of reasoning?
You have so far established your T12 clone warms up much faster from cold. The rest of your statement is not clearly supported. Perhaps your T12 clone is better at thermal regulation. Ok.* But you assume it is because the heater is in the tip; you assume this improves thermal regulation because of "lag." There are some improvements from putting the heater in the tip, but I don't think this is one of them. The heater/sensor setup in the T12 actually causes a new problem when it comes to regulation, which I can try to explain, but not right now.

Quote
Quote
which means the heating element has gotten to temp (330 C), not the tip.
There are no assumptions in that statement. Care to point them out?

You suggest that from a cold start the 888 sensor will reach/report the set temp significantly before the tip will reach the set temp. I assume the other way. Since you are concerned with the lag, well here it is. On a cold start, this is where I suspect an 888 will demonstrate the greatest lag, resulting in the most egregious overshoot. After the sensor's thermal mass is fully to temp, the system is now working in calibration, and overshoot is not a significant problem that needs to be solved (IMO). But on that first startup; there is your improvement. So to suggest what you did, I suspect you are counting your chickens twice.

Maybe sometime later this month I will have the time to test this. 

*which one is it, and what tips do you use?  Perhaps I will buy one for fun.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Tarloth on September 07, 2019, 02:34:22 am
But if I need to dial up/down the temp a bit from the preset temp, the menu diving must be engaged.

When you need to touche the temp "a bit"?. I f you need to touch 2 degrees for a better soldering it's a mistake or something else, generally when any temp it's not sufficient, then increment 10 or 20 degrees it's necessary. It's the next point of the presets and access it by one button. I not know any professional solder that touch the temperature "a bit", or the temp it's OK or move up or down almost 10 c degrees. I prefer the dial too, I use it for two decades, but using the preset it's not a problem to me.

Quote
I never heard of Edsyn until this thread, and the 951sx looks well worth considering.  It has a good old temp knob, no digital controls.

I never heard of it and it's more expensive that other complete tested solder stations of well knowed brands. Technology seems to me the same than the 936, that was OK 20 years ago. I not know the quality of the tips but seems not so good for me and again, technological oldest or same than the 888. I'm wondering why are only few recent reviews and all of them was by hobbyst.

Quote
And it doesn't look like a toddler's toy. [/quore]

But isn't a toy, A yellow ferrari seems to me ridiculous but is still a ferrari.


Quote
And I don't care that much about the color scheme, but the overall design just seems anti-user to me.  At least the Edsyn tried to be space saving, which shows consideration in the design.  For just a little more money than the Hakko, I think the Edsyn would be the best option for me.

Everyone has their opinion about their own tastes, I bought the European FX-888D (silver design) because I don't like yellow in general . But if this Edsyn welding station were cheaper than a Hakko or Weller, I would think so, but being 60% more expensive, I would buy without hesitation something more modern or buy a brand with more trajectory more reviews and user experience. Why not ask in this forum if somebody uses it and evaluates how much answer obtain?
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 07, 2019, 05:37:27 am
Quote
When you need to touche the temp "a bit"?. I f you need to touch 2 degrees for a better soldering it's a mistake or something else, generally when any temp it's not sufficient, then increment 10 or 20 degrees it's necessary. It's the next point of the presets and access it by one button. I not know any professional solder that touch the temperature "a bit", or the temp it's OK or move up or down almost 10 c degrees. I prefer the dial too, I use it for two decades, but using the preset it's not a problem to me.
I used to adjust my analog 888 without looking at it. But punching in the temp is actually useful and practical for production soldering, and once you get the hang of it, it gets you dialed in faster and is repeatable in case you have some recurring job in a production cycle. I will fidget with temp down to 5 degrees C, at least.

It is also useful for noticing problems sooner. Say when your tip is starting to oxidize and needs a good cleaning. You can't argue with a number. With a dial, you might shrug, bump the dial up a bit, and carry on crippled, just masking some other problem.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Tarloth on September 07, 2019, 07:30:39 am
I calibrate all of my soldering stations in the last 30 years once a month aprox. At the beginning using the eutectic point as reference and few last years an clone of Hakko thermometer. When I doubt I calibrate all of them again with the eutectic point or a laboratory calibrated TC in a solder bath.

When I working if need some extra heat touch the preset to next, when I finish this defiant joint,  I touch to down one preset.

I miss the dial because I'm getting older and remember my years   when the 936 was gorgeous and solder a euroconnector was the challenge. But really, to be fair, I not need dials any more. 98% of the time I have the temperature setting to 300 if use PB or 350(325 for tiniest smd) if use Pb free. My presets are (always) 275/300/325/350/400 centigrade degrees and really few times in 20 years I did need to use it higher than 400 degrees. In fact, few time a year I need to use the last preset.

I change tips geometry all the time but not the temperature, because of that I really not understand the obsession for change the temperature all the time or fancy interfaces.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 07, 2019, 04:24:42 pm
On the Hakko FX-888D, it does still seem like the best positioned soldering station at a  hobbyist price level for the quality.  But I really don't like what I have seen of the interface, personally.  Hakko went from a good functional design (936), to a somewhat uglier but still good enough design (FX-888 non-digital interface), to the worse interface design of the FX-888D.  And if I bought an FX-888D anyway, that sends a signal to Hakko that a customer is ok with a bad design choice.  Probably the only way that manufacturers will correct bad design choices is if customers don't buy those products until the corrections are made.

I did look at the various T12 compatible and other newer tech (JBC, etc.) clones, but I kept running into users talking about problems with those stations.  Safety problems due to poor design, other circuit level issues, firmware issues, and poor quality issues.  Again, if I were to buy one of these stations, that sends a signal to the manufacturers that these sorts of issues are acceptable.  And given that these clones are much lower cost than the originals designs, if I buy one that sends a signal to the manufacturers that a customer is ok with poorer quality in trade for a lower price, including potentially dangerous design choices.  Losing sales to lower quality clones sends a signal to the makers of the originals that lower cost is preferred over acceptable quality.  And nearly all of those issues seem so trivial for manufacturers to correct, but they don't seem very concerned with doing so vs. selling more units without the issues corrected.  Also, these low cost clones seem to have hidden costs, where many users of these stations mention poor quality of the included irons, tips, and stands, recommending upgrading these items in order to get the benefits of the newer tech.  And some of them don't include power supplies and stands at all.  So overall to me, these stations seem less like finalized quality made tools ready to put to use and more like hobbyist projects in themselves, where the game is trying to beat out prices of the original designs in trade for lower quality.  I'm struggling to come up with a good description for this, but I guess I would call it, design quality noise.

And what the heck is up with Weller not putting fuses in their stations?  Good on Dave and others for pointing that safety issue out.  It seems like it would be such a trivial matter for Weller to correct this issue, making their stations a decent option for hobbyists, but they just don't do it.  Even the lowest cost no-name stations have fuses.

On the Edsyn 951SX, I think they aren't aimed at the hobby level.  They seem to be aimed at production.  At $160 price point (station price + shipping), it probably isn't the best option for a hobbyist station.  But I found a used 971 station for half the price of the 951SX (which is 25% price of a new 971), which makes taking a gamble on it much more sensible.  If it arrives with a functionality problem, I can always send it back.  And if it works as it should but I end up not liking it, I can always resell it.  The product descriptions of the Edsyn stations seem a little vague to me, but from what I could gather, the 971 should have faster heat-up and recovery times than the 951SX, and the iron accepts a wider range of tips than the iron that comes with the 951SX.  And I did find some radio and amp repair guys recommending Edsyn soldering stations on other discussion forums, as well as other miscellaneous recommendations.  If it arrives in good working order, I'll open it up and take some pics of the guts, in case anyone is curious.  And I'll see if I can work out a way to test the heat-up and recovery times.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 11, 2019, 03:55:02 am
The results with the T12 clones seem to vary a lot. Some people have good results while others are total shit. Some people have multiple units with either result. I've been bitten by a well regarded cheap soldering station before and regretted not spending a bit more on a decent and proven station.

Yeah, I mentioned that too in a previous post. I think this is an inherent problem with things that are built to BOM price + a little extra. There's no room for QA and no room for extra care, so you always get a rushed job (of an otherwise good design - maybe).

 I know it's been a few days since you wrote that (I've resurrected threads that had come to a standstill months earlier - this is an 'early intervention' by my standards :) ) but you've hit the nail squarely on its head regarding all those KSGER T12 soldering stations that Banggood had been dishing out willy nillly to every celebrity Youtube reviewer in sight over the past 12 months or so.

 The only good thing about this being the fact that most of the reviews were honest appraisals despite one or two failures to spot the glaring safety issues in the controllers which were later corrected for in follow up reviews. Suffice to say that I could see the good side of these KSGER soldering stations and knew all I needed to turn yet another Chinese "Sow's Ear"[1] into a silk purse (both in terms of electrical safety and excision of the more mundane "accidents waiting to happen" poor quality workmanship in the wiring of the handles) when I ordered one from Banggood on the strength of all those reviews.

 I know there are some idealists who argue that we shouldn't reward such shoddy design and workmanship by choosing such Chinese Junk over the more expensive western manufactured 'junk' (unfused Weller soldering stations anyone?) but we don't live in an ideal world were such "Protest by not buying" could possibly work.

 As far as I'm concerned, I'm living in a world where I seem to be outnumbered a million to one by people who don't give a shit how things work, just as long as they work (whether by technology or black magic - it's all the same to them) to provide them with today's modern version of Ancient Rome's "Bread and Circuses".

 I'm not claiming I'm any better than the uncurious majority of my species, just stating how it is. It's a lot more complex than what I care to expand upon, suffice to say that it's now very obvious that human civilisation (is there any other kind?) is now inexorably headed to Hell in a handbasket of its very own making and the best we can do as we each continue life's journey is to make ourselves as comfortable as possible for the rest of our journeys to the grave (in other words, "Business as Usual").

 That being said, I'm more than happy to accept such cheap Chinese technological marvels, "warts and all", safe in the knowledge that I can render them not only fully functional but acceptably safe to use in regard of the risks of electrocution and/or any threat of fire they may pose.

 At least I have the comfort of knowing by personal inspection (and, where needed, intervention) just how safe and functional they are, unlike the case with goods of western manufacture where we only have the assurance of conformance to government mandated/enforced safety standards to place our faith in, aided by a free press to ensure these standards are applied and maintained. :-DD I'm not a very trusting person when it comes to matters that concern my own safety. ::)

 Yes, these otherwise excellent KSGER T12 soldering stations do have some serious safety issues (along with the more mundane issues of poor workmanship in the assembly of their various soldering handles) so I definitely wouldn't recommend them to complete novices looking to buy their very first soldering iron. You need a collection of soldering irons and the skill to use them to rework these soldering stations into safe and functional devices before you can even chance trying them out without at least the protection of thick rubber gloves.

 For those of you with a hobby level interest (professionals with access to soldering kit costing thousands of dollars need not read any further), this KSGER soldering station is your chance to (effectively) monetise your skills, perhaps even justify the expense of that 180 watt Parkside soldering gun you bought a year or two back and only used once in anger by making good use of it now in sweating the diode heatsink off the PSU board to file the end fins down so they clear the solder resist mask that was their only protection against contact with a circuit trace carrying (in my case -UK mains voltages) the 340 volt dc on the big mains rectified supply smoothing cap right next to that end of the heatsink.

 It could also be useful in soldering an earthing tail to the soldering iron socket as a means of earthing the metal case without having to drill a hole and fit an earth terminal (the iron itself was the only bit of touchable metalwork that was actually connected to the earth pin of the C14 mains socket).

 If you'd bought the cheaper plastic cased version, this obviously doesn't apply (and quite possibly in this case, there's a fair chance of it using a slightly different design of PSU board free of this defect). My concern is with the better quality extruded aluminium cased version which I'd chosen specifically for both this and the fact that it was supplied with the "cheap 'n' nasty" plastic soldering handle which I preferred for its simple push fit tip changing feature, light weight and, most importantly, its very short tip to grip working distance which trumps all other considerations imo, oh, and not forgetting its "starter" T12-K tip which most of the alternative options either left out or else cursed with a small collection of tips provided simply as an excuse to inflate the price.

 The user interface seems to have been well thought out imo. A rotary encoder with click stops and a push operation being the sole interface input control provides a compact and usable interface. No hunting for the 'right button' to press and no complex to navigate menu system for normal use.

 For those of you who haven't viewed the many youtube reviews on the KSGER and have expressed a strong dislike for the way some 'updated' soldering stations have had their 'new fangled' digital interfaces (badly) implemented, here's a brief run through of "normal use" with the KSGER unit:-

 Dialing the temperature up and down in increments of your choosing, a simple push to take it out of sleep or standby to your preset temperature (which you can adjust up and down in preset increments of your choosing), a quick twist three clicks to the left to put it straight into standby, if you don't wish to wait for your programmed timeout to expire and do this for you at a setback temperature of your choosing, another three clicks left from there to take it straight back to sleep if you don't want to wait for your programmed timeout to expire and do this anyway, a similar three clicks to the right if you want a timed temperature boost of your choosing with a similar leftward twist to cancel it early - what's not to like about this little soldering station?

 For anyone who hasn't already seen the many youtube video reviews on these KSGER units, I can only suggest that it would be worth taking some time out to watch a few of them. It's not all 'sweetness and light' even after all the safety and wiring issues have been addressed.

 There does seem to be a peculiar need for each brand new tip to be submitted to a "burn in" process before you can achieve stable temperature control over the tip. However, once "burnt in", they seem to perform just fine thereafter.

 There is obviously some initial change taking place with a new never before used tip, when it is used for the very first time, which destabilises the PID control algorithm during the first few minutes of attempted use. With a dialled in temperature of 300 deg C, it only takes 2 or 3 minutes to settle down sufficiently to be usable. I have noticed, however, that selecting higher temperatures (350 or 400 deg), the instability returns again at these elevated temperature settings, requiring an even longer period to settle down.

 Unfortunately, trying to speed this "burn in" period by selecting 480 deg doesn't seem to be any help (you can see the power percentage alternate between 0 and 100 instead of settling at or around a sane average such as say, the 18 to 28 percent mark seen at the lower 300 deg setting.

 Whilst I've done a modest amount of soldering at the 300 deg setting during the past 4 weeks that I've had it in my possession, I haven't had much chance to experiment with this "burn in" process to the higher temperatures with my remaining unused tips to come to any definite conclusion as to how severe an issue this would be in practice.

 I did notice, after persuading a tip to stabilise sufficiently at around the 450 deg setting, that running the tip sensor calibration process would improve the situation somewhat but I still felt the need to re calibrate again before seeing sufficient stability at the 450 and 480 degree settings, settings I don't plan on using on a regular basis, if at all, anyway simply to avoid unnecessary stress on tip life.

 One thing I did learn (the hard way - how else!) was that when checking tip temperatures with one of those thermocouple thermometers designed for this job, it's all too easy to mistake the variations in temperature for poor thermal contact when checking a brand new tip that hasn't yet stabilised.

 You land up feeding it fresh solder attempting to get an improved thermal contact and stable reading when the problem all along is actual temperature variation of the tip itself so you find yourself playing a futile game of "Chase Will o' The Wisp".

 In this particular game, it's "Five strikes and you're out!" rather than the more common three strikes so beloved of American baseball fans and that of their legal system. I'm now down one thermocouple - it fell apart on me. >:( Never mind, at least I've still got another four left to burn out. ::) At this rate, I'll be adding a pack to my next Banggood order within the next month or so.

 Unfortunately, this makes calibrating a new tip next to impossible until it has achieved some level of stability at the 450 deg mark since this is the starting point for the calibration process which also uses 350 and 250 degree calibration temperature points to complete the procedure. Whilst a calibrated tip seems to achieve improved stability more quickly, it's a bit of a "Catch 22" situation.

 Anyhow, this is the only troublesome aspect of my improved KSGER soldering station. It could simply be an issue that afflicts only the clone T12 tips but I'd have to invest just about what I paid for a ten pack of these in order to buy just one genuine Hakko tip to test this hypothesis so I'll persevere for now. In the end, it may come down to splashing out on a genuine Hakko tip but I'll save that option for later consideration.

 Of course it's quite possible that this "burn in" characteristic has always been a feature of the original Hakko tips but was never noticed on the more conservatively responding Hakko soldering stations and is only now being revealed by the use of the KSGER's more aggressive PID control algorithm.

 KSGER may even have decided that, since it's a relatively short lived phase of the tip's total service life, it would be best to take the long term view and not to try to accommodate this initial short lived behaviour and let the end user deal with this minor inconvenience of having to 'burn in' new tips.

 Needless to say, I'd be very interested in seeing a video review where brand new Hakko tips are tested in one of these KSGER soldering stations for just such behaviour. It could save an unnecessary expense on my part (and no doubt many others if the same behaviour is revealed with genuine Hakko tips).

 Other than that downside with the need to run in new tips, this KSGER soldering station seems to function very well. Indeed it seems to offer better performance than the original Hakko soldering stations were able to offer with the T12 and T15 tips.

 Bear in mind that I've only actually had experience of the basic Antex soldering irons, an ancient 120W Weller soldering gun, long since burnt out and now replaced with a cheap Parkside 180W soldering gun that looks like a Russian knock off of that ancient Weller. The rest is simply what I've gleaned by watching youtube review videos and taking note of their comments.

 Going from my own experience, this is a vast improvement over my previous Antex based soldering iron usage where I now no longer have to agonise over whether to switch the Antex off to save wear on its tip and heating element whilst it roasts itself to an early demise keeping a soldering iron holder nice and toasty in between soldering activity when I spend the next "10 to 15 minutes" prepping the next lot of joints to be soldered which typically takes a lot longer than anticipated, or else switch it off and risk the need to solder another joint or two just after it has cooled down and be forced to allow it more time than it really needs to get back up to its unregulated soldering temperature. I reckon my irons have spent more than 90% of their on time just idling away in the iron holder, literally burning themselves up for no productive purpose.

 Being able to stop worrying about leaving an iron running hot and idle is the main bonus I'm getting with this soldering station. The temperature control and almost threefold power rating over my 25W Antex is the icing on this particular cake for me. :)

 Others more used to a 70 to 120 watt soldering station setup, otoh, may not regard this as much of an improvement, especially when you take into account the need for so much electrical safety remedial work being required to make it sufficiently safe for peace of mind. That business with the need to 'burn in' new tips could prove to be the "Last Straw" as far as anyone considering it as a cheap alternative to a brand named replacement for their venerable soldering station setup that's seen better days.

 Of course, anyone with a set of genuine Hakko T12 or T15 tips might regard this as an attractive alternative to their existing bulky and klunky soldering station(s), especially if the thought of reworking the PSU to resolve the safety issues holds no terrors for them (and likewise for the handles).

 Anyway, those are my observations and views on the cheap Chinese made KSGER Soldering stations for what they might be worth. If you haven't already done so, you can find more information by checking out the several video reviews of the various KSGER soldering station options on youtube.

JBG

[1] I've had plenty of experience of Chinese 'skimping' during the last nine months or so with the (in)famous FY6600 arbitrary wave function signal generator manufactured by Feeltech (now rebranding themselves as "FeelElec"). Not so much electrical safety, although there was an element of this with regard to the floating grounds carrying the inevitable half mains live 'touch voltage' common to all Class II smpsus fitted with the mandatory EMC reduction Class Y capacitor which represented an element of ESD risk to any device being tested. It was more a case of overcoming "Bean Counteritus" where the accountants are given more control over design and manufacturing than sanity would otherwise dictate.

 Although the problems with the KSGER unit looked typically Chinese in character, what was novel was the fact that such safety issues in an item intended for sale to Western Civilisation should be so blatantly overlooked to the point they were. If I hadn't seen it with my own eyes, I wouldn't have believed such disregard for safety was even possible, not even by the Chinese. Of course, I'm a little older and wiser now so such shoddiness by the Chinese will be assumed until verified otherwise from now on with any further purchases of electrically powered Chinese manufactured goods.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: blueskull on September 11, 2019, 04:21:29 am
If a good quality Chinese station is the goal and you don't want to trust someone unknown messing with mains connection, why not getting a TS series and get a good, known brand AC adapter?
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: GreyWoolfe on September 11, 2019, 01:44:50 pm
I did look at the various T12 compatible and other newer tech (JBC, etc.) clones, but I kept running into users talking about problems with those stations.  Safety problems due to poor design, other circuit level issues, firmware issues, and poor quality issues.  Again, if I were to buy one of these stations, that sends a signal to the manufacturers that these sorts of issues are acceptable.  And given that these clones are much lower cost than the originals designs, if I buy one that sends a signal to the manufacturers that a customer is OK with poorer quality in trade for a lower price, including potentially dangerous design choices.  Losing sales to lower quality clones sends a signal to the makers of the originals that lower cost is preferred over acceptable quality.

One thing my dearly departed father taught me is to buy a tool right and buy it once.  In everything, it seems people are only interested in price.  A cheap price for almost good enough is fine.  NO, it is not.  No one thinks about total cost of ownership.  How much is your time worth to modify your product to work better, be safer, etc?  How much is your time worth to repair your product sooner/more often due to shoddy workmanship/sub par quality parts?  How much is your aggravation worth when it under performs?

I get it that we have a lot of advantages on this side of the pond.  I have what I have, a Hakko FX-951 and a Metcal MX-500 with wand and tweezers, because Mrs GreyWoolfe let me clear out the garage of stuff we weren't using.  Otherwise, I would still have my Hakko 936.  Save your spare change in a big jar until you have enough to get something better and something that will last a long time.  I am not going to debate what to buy.  There are too many fanboys here.  I love my Hakko and Metcal, Shock almost sounds like a distributor for Weller :-DD.  Read the spec sheets, watch videos and read reviews, always taking them with a grain of salt.  You will learn to separate the wheat from the chaff.  Then make a plan to save what you need to get to where you want to be, it is worth the wait.  Instant gratification isn't long lasting.  I spend a lot of time researching everything I buy, no matter how small and then I buy with confidence I purchased well.  I almost never return anything because I did my best to make an informed purchase.  Usually, when I make a snap decision to buy, I get burned.  However, I should have listened to Mrs GreyWoolfe and bought the commercial paint sprayer for $60 at a yard sale.  It would have worked far better than the Wagner paint sprayer I have. |O |O
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: martin1454 on September 11, 2019, 01:51:53 pm
One thing my dearly departed father taught me is to buy a tool right and buy it once. 

One that I have learned and started to use a lot is:

Buy the cheap one at first and use that - If it breaks, then it means then you can go buy a expensive since it means that you used it to a degree where a better one is needed.

On the otherhand, I often have to use a tool like 1 time every 5 year, and for that, the cheap one will never break
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 11, 2019, 02:54:42 pm
There are too many fanboys here.  I love my Hakko and Metcal, Shock almost sounds like a distributor for Weller :-DD.

Weller? how dare you :). Hakko, Pace and Metcal are the only stations I recommend. The Hakko FX888D, Pace ADS200 and Metcal MX5000 would be my "beginner", "prosumer" and "money bags" choices.

In the past I've also recommended the FX951 a few times, this was prior to the Pace ADS200 being released. I have no problems recommending something (even though it's not for me) as long as it's reliable and good value for people.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 11, 2019, 03:23:36 pm
If a good quality Chinese station is the goal and you don't want to trust someone unknown messing with mains connection, why not getting a TS series and get a good, known brand AC adapter?

 The price? :)

 Seriously though, to some extent I love getting hold of a "bargain" that I know how to easily fix so only the "Good" remains. I'm a retired GPO/BT engineer with more than a passing interest in electronics and technology and science and plenty of time on my hands to pursue my interests.

 This interest of mine in repairing stuff, broken by design (broken by "beancounteritus" in reality) goes back half a century with Japanese and European goods - China is just the latest manufacturing country to join this club started by PT Barnum with his false, misleading promises to the great (unwashed) consumer over a century ago, kick starting the whole advertising industry with its abiding principle of "Never give the sucker an even break" (a paraphrasing of, I understand, a quote misattributed to this famous showman).

 Make no mistake, the whole business of selling is psychological warfare and we, the consumer, have been on the losing side ever since PT Barnum demonstrated the effectiveness of such salesmanship. The Maddison Avenue lot must be offering their tame psychologists the highest salaries such experts could ever hope to attain.

 The consumer is fighting a losing battle they mostly aren't aware of being participants in, thanks to the cunning use of psychological tricks to disguise this fact. The advertising execs are so confident of this, they even openly refer to their advertising as "campaigns", a description taken from the dictionary of military expressions.

 If everyone took to my point of view, the whole of human society would collapse and we'd belatedly stop polluting the world's oceans and atmosphere. Belatedly because we've allowed our technological prowesss to outstrip our ability to deal with the consequences and I have no ideas as to how we can fix this. It's easy to spot our mistakes in hindsight but far harder to have taken corrective action in time. Keeping tabs on all the inventive ways we can sleepwalk our way into extinction is rather like herding cats.

 However, I digress. With regard to that wonderful mix of danger and delight represented by the KSGER soldering stations (getting back on topic), I'm rather impressed by the way it so cheaply improves on the old mains powered soldering iron technology with its pragmatic choice of uncontrolled heat somewhere between just hot enough for the job and just cool enough not to go into meltdown when parked in a soldering iron holder between soldering operations (I'm easily impressed).

 As for my interest in such cheap, readily repaired gear that's been pre-broken by "beancounteritus" afflicted design, that's simply my way of amusing myself to retain some semblance of sanity between now and my ultimate fate, the efficacy of which is somewhat debatable. I offered my thoughts on the subject as to the question of whether the "Hakko still the best option for a good quality hobbyist soldering station?" which boils down to this:-

 The Hakko direct drive tips are a good choice whether cheap clones or expensive originals but, in view of a refurbished KSGER controller or similar unit designed for the T12/T15 tips doing a better job than the original Hakko controllers and so cheaply, I'd say go for the Hakko tips and use them with a KSGER controller instead.

 At less than 30 quid for the model I was describing (I'd paid ten quid more for mine just four weeks ago), I'd say it's well worth taking a punt if you're prepared to do some basic remedial work to render it safe and fix any bad soldering in the supplied handle. At worse, you land up with a spare second best soldering station control unit for your genuine Hakko soldering station setup.

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: rsjsouza on September 11, 2019, 03:44:08 pm
One thing my dearly departed father taught me is to buy a tool right and buy it once. 

One that I have learned and started to use a lot is:

Buy the cheap one at first and use that - If it breaks, then it means then you can go buy a expensive since it means that you used it to a degree where a better one is needed.

On the otherhand, I often have to use a tool like 1 time every 5 year, and for that, the cheap one will never break
I learned what GreWoolfe said as well, but over the years seeing some needs for equipment that would be rarely used, I ended up adapting to the "cheap when scarcely used" model as well. 

 
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: AngusBeef on September 11, 2019, 04:34:21 pm
One thing my dearly departed father taught me is to buy a tool right and buy it once. 

One that I have learned and started to use a lot is:

Buy the cheap one at first and use that - If it breaks, then it means then you can go buy a expensive since it means that you used it to a degree where a better one is needed.

On the otherhand, I often have to use a tool like 1 time every 5 year, and for that, the cheap one will never break
I learned what GreWoolfe said as well, but over the years seeing some needs for equipment that would be rarely used, I ended up adapting to the "cheap when scarcely used" model as well.
If it's something you will use all the time, buy the highest quality you can afford

If it's auto parts, buy mid grade

If it's tools and parts that mostly sit on a shelf, find the cheapest that works
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 11, 2019, 04:43:02 pm
I did look at the various T12 compatible and other newer tech (JBC, etc.) clones, but I kept running into users talking about problems with those stations.  Safety problems due to poor design, other circuit level issues, firmware issues, and poor quality issues.  Again, if I were to buy one of these stations, that sends a signal to the manufacturers that these sorts of issues are acceptable.  And given that these clones are much lower cost than the originals designs, if I buy one that sends a signal to the manufacturers that a customer is OK with poorer quality in trade for a lower price, including potentially dangerous design choices.  Losing sales to lower quality clones sends a signal to the makers of the originals that lower cost is preferred over acceptable quality.

One thing my dearly departed father taught me is to buy a tool right and buy it once.  In everything, it seems people are only interested in price.  A cheap price for almost good enough is fine.  NO, it is not.  No one thinks about total cost of ownership.  How much is your time worth to modify your product to work better, be safer, etc?  How much is your time worth to repair your product sooner/more often due to shoddy workmanship/sub par quality parts?  How much is your aggravation worth when it under performs?

I get it that we have a lot of advantages on this side of the pond.  I have what I have, a Hakko FX-951 and a Metcal MX-500 with wand and tweezers, because Mrs GreyWoolfe let me clear out the garage of stuff we weren't using.  Otherwise, I would still have my Hakko 936.  Save your spare change in a big jar until you have enough to get something better and something that will last a long time.  I am not going to debate what to buy.  There are too many fanboys here.  I love my Hakko and Metcal, Shock almost sounds like a distributor for Weller :-DD.  Read the spec sheets, watch videos and read reviews, always taking them with a grain of salt.  You will learn to separate the wheat from the chaff.  Then make a plan to save what you need to get to where you want to be, it is worth the wait.  Instant gratification isn't long lasting.  I spend a lot of time researching everything I buy, no matter how small and then I buy with confidence I purchased well.  I almost never return anything because I did my best to make an informed purchase.  Usually, when I make a snap decision to buy, I get burned.  However, I should have listened to Mrs GreyWoolfe and bought the commercial paint sprayer for $60 at a yard sale.  It would have worked far better than the Wagner paint sprayer I have. |O |O

 Your father's advice was spot on at the time but, sadly for us all, it's a rather different world today as a result of the ever increasing pace of technological development, the consequences over which we have increasingly less control. These days, we now have to temper that sage advice with a dose of pragmatism.

 I've never used anything more sophisticated than an Antex 25 watt mains powered soldering iron with no temperature control beyond mains voltage excursions and an ancient, now long defunct, 120W Weller soldering gun so can only go by what I've seen in youtube reviews of Hakko soldering stations which now seem to be obsolescent technological 'Dinosaurs' compared to the cheap 'n' dangerous KSGER units with their slick and sophisticated user interface and quick response PID control algorithms and all encompassing user preference tuning options.

 The only downside to which that I can see is that their end of life repurposing as door stops won't come anywhere near as close to the efficacy as such promised by the Hakko units should they eventually fail. The trouble with your father's advice today is that you may find yourself investing a lot of your hard earned in something that's destined to outlive its usefulness. Sad but essentially the truth of the matter.

 Obviously, that advice still applies with non electronic tools such as hammers, chisels, screwdrivers and such but anything more sophisticated will be prey to the effects of modern day planned obsolescence and, as such, introduces an element of pragmatism into your purchasing decision, especially when money is tight.

 In a cash strapped hobbyist context, the advice to buy a cheap example so you can "Suck it and see" to get a better idea of your requirements with the later option of making a more informed purchasing decision of a better quality version is today's new "Sound Advice". In a professional or semi-professional context where your employer or your business foots the bill, a totally different set of considerations apply.

 There are no hard and fast rules in this game. A well informed cash strapped hobbyist might well elect to skip the 'cheapest possible' option and go straight for the 'best bang for his buck' choice in spite of its "at first sight, exorbitant price", aided no doubt by the knowledge that he's avoided wasting a small chunk of his money in a 'waste of space cheapy'.

 These days, a lot of tools can be treated as disposables with fewer and fewer being regarded as longer term capital investments. I suspect that even for a lot of cash strapped hobbyists, these KSGER units fall into the 'disposable' class despite the ready availability of spares to keep them going if needed.

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 11, 2019, 10:26:29 pm
Quote
Going from my own experience, this is a vast improvement over my previous Antex based soldering iron usage where I now no longer have to agonise over whether to switch the Antex off to save wear on its tip and heating element whilst it roasts itself to an early demise keeping a soldering iron holder nice and toasty in between soldering activity when I spend the next "10 to 15 minutes" prepping the next lot of joints to be soldered which typically takes a lot longer than anticipated, or else switch it off and risk the need to solder another joint or two just after it has cooled down and be forced to allow it more time than it really needs to get back up to its unregulated soldering temperature. I reckon my irons have spent more than 90% of their on time just idling away in the iron holder, literally burning themselves up for no productive purpose.

 Being able to stop worrying about leaving an iron running hot and idle is the main bonus I'm getting with this soldering station. The temperature control and almost threefold power rating over my 25W Antex is the icing on this particular cake for me. :)
This is one way to skin a cat. If you are soldering heavy boards that require high set temps, this soldering paradigm is probably practical. Pick up iron, few seconds to warm up out of sleep, solder a joint, set the iron back down. And the T12 is certainly good at coming out of sleep, quickly. I think my T12 clones would be better at this than an 888. If this is you, this is a good iron and a step up from the old stuff.

The reason why the the 888 is simply better than my T12 clones, for me, is that most of what I solder I can do at temps low enough to not bother with sleep; not that I like to admit it, but I can and have left my iron on all night and started soldering the next day without even cleaning the tip, first. The 888 might not have as much power, but it has tighter temp regulation, so it can solder at a lower set temp. Probably 10-25C. And when I do production soldering, this is not just one joint then put the iron down. It's soldering scores of joints in succession for minutes at a time, so a lower set temp matters more than being fast out of sleep. Most hobbyists probably just need the tip to get plenty hot for a short spell, intermittently, and a bit hotter of a set temp doesn't really make a difference.

The burn-in. I agree it sounds like the KSGER possibly does a more aggressive compensation for an inherent con of the T12 tips (the sensor is directly coupled to the heater; not desirable). Might have to test it.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: bd139 on September 11, 2019, 10:34:00 pm
Just chipping in here. I am convinced the T12's are a piece of shit. I've had two and I was not impressed. When they work they are pretty good but the whole ecosystem is tuned to failure. Firstly the isolation and safety arrangements in them are somewhere between absolutely dire and murderous. Literally the mains connector is lap soldered onto the case. Earth is just WTF. Secondly the quality is very poor. The handpiece on mine was so poorly engineered, the tip shorted out at the contact level and blew the crap out of the controller. Thirdly the stand situation is terrible. It's like that scene in Men In Black where they're sitting in the chairs trying to write stuff. Absolute piece of crap. I actually took mine in the garden and hurled the bastard onto the roof of my neighbour's garage where it lives to this day.

This is something they could fix with quality control but I suspect they are designed for the home market where keeping costs down trading off safety is the win. I'm not getting into the KSGER vs Quicko vs X vs Y thing; they are much of a muchness.

As mentioned earlier, buy once. I bought the ass end Metcal PS900 and the thing is manna from heaven. You can solder tits onto a snake with it.

If that's too pricey it has to be a genuine Hakko. I was put off by the poor supply chain in the UK for their stuff so opted to go pricey.

Also lets not forget the "manky old Weller TCP" which is obtainable on ebay for less than half a Hakko at average, all the parts are still available and it'll be there after world war three armageddon with the cockroaches and my mother-in-law.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 14, 2019, 05:27:24 am
Quote
Going from my own experience, this is a vast improvement over my previous Antex based soldering iron usage where I now no longer have to agonise over whether to switch the Antex off to save wear on its tip and heating element whilst it roasts itself to an early demise keeping a soldering iron holder nice and toasty in between soldering activity when I spend the next "10 to 15 minutes" prepping the next lot of joints to be soldered which typically takes a lot longer than anticipated, or else switch it off and risk the need to solder another joint or two just after it has cooled down and be forced to allow it more time than it really needs to get back up to its unregulated soldering temperature. I reckon my irons have spent more than 90% of their on time just idling away in the iron holder, literally burning themselves up for no productive purpose.

 Being able to stop worrying about leaving an iron running hot and idle is the main bonus I'm getting with this soldering station. The temperature control and almost threefold power rating over my 25W Antex is the icing on this particular cake for me. :)
This is one way to skin a cat. If you are soldering heavy boards that require high set temps, this soldering paradigm is probably practical. Pick up iron, few seconds to warm up out of sleep, solder a joint, set the iron back down. And the T12 is certainly good at coming out of sleep, quickly. I think my T12 clones would be better at this than an 888. If this is you, this is a good iron and a step up from the old stuff.

 This is me right enough! :)  I've been examining this whole business of using thermocouple sensing for temperature regulation of soldering iron tips over the past few days (hence the delay in replying to this post).

 It turns out that this clever way to sense actual tip temperatures is riddled with several practical limitations over and above that of simply maintaining a tight coupling between 'cause and effect' in these cartridge styled soldering tips where the heating element and the thermocouple sensor are integrated as closely as possible to "the business end" of the tip in order to minimise the errors caused by thermal lag and temperature gradients.

 These modern electronic control systems were designed to offer more flexibility of temperature control over that of the earlier Curie point temperature stabilisation method which had relied on the user having to choose from a selection of tips with a temperature setting that had been defined during their manufacture.

 It turns out, the task of getting such a "direct drive" thermocouple based control system to perform well is a lot more complex than the thermostatically controlled immersion heater model would suggest as I've recently been finding out.
 
The reason why the the 888 is simply better than my T12 clones, for me, is that most of what I solder I can do at temps low enough to not bother with sleep; not that I like to admit it, but I can and have left my iron on all night and started soldering the next day without even cleaning the tip, first. The 888 might not have as much power, but it has tighter temp regulation, so it can solder at a lower set temp. Probably 10-25C. And when I do production soldering, this is not just one joint then put the iron down. It's soldering scores of joints in succession for minutes at a time, so a lower set temp matters more than being fast out of sleep. Most hobbyists probably just need the tip to get plenty hot for a short spell, intermittently, and a bit hotter of a set temp doesn't really make a difference.

 Actually, as one of the things I've been finding out, the excess power rating of these thermocouple controlled tips is mostly to provide a rapid warm up and fast response against the cooling effect of soldering small to medium thermal masses typically encountered on PCBs.

 For the very first time ever, I used my Daniu FG-100 clone tip thermometer to check the tip temperature on my 25 year old Antex XS25 230vac mains soldering iron to see how hot it manages to get when left in the iron holder for more than quarter of an hour. It took some two or three minutes just to get up to 300 deg btw and some 15 minutes later it had topped out at 426 deg. I suspect, given another half hour it would probably have ultimately reached 430 deg with its 25 watt heating element warming a bit that approximates the T12-BC3 that I've currently gotten burnt in with the KSGER controller.

 Checking the average percentage figure, now that the BC3 tip has stabilised at 450 deg and above temperatures, I see 7% at 300 deg and 14% at 430 deg when it's parked in the holder. Assuming a 100% figure equates to 72 watts, the resulting 5 and 10 watts drive power seems in line with the Antex's use of 25 watts to drive a tip with just over double the effective surface area of the BC3 tip in a T12-9501 handle.

 One significant observation I've noted (prompted by this whole business of "tip burn in") is that once a stabilised tip has been set to the maximum of 480 degrees, the percentage of power, after the initial burst of accelerated heating at 100% for the first second or so, it soon drops down long before it gets to within 50 degrees of the target temperature to just 15%. Hitting the 50 deg boost, the percentage reading dances between 0 and 45 deg suggesting an average heating power of just 15 to 16 watt being applied to achieve an "indicated" temperature of 530deg from a 72 watt rated tip.

 I used quote marks around that "530 deg" figure because it's what the controller believes it's seeing from a tip that's never managed to top 470 deg, according to my tip thermometer (which I have suspicions of in regard of its (apparent) lack of cold end temperature compensation - more of that anon). What I suspect the problem is with tip temperature stability in this case is the use of a 24.5v supply with a controller designed to work over the 12 to 25 volt range where the optimum voltage would be around the 20 volt mark (optimum balance between control and stability of temperature).

 The clue to this lies in the default (5S lipo battery's worth - the smpsu voltage corresponds to a 6S Lipo pack) alarm voltage of 18.5 and cut off voltage of 18.2 (from memory - I forgot to take note before exploring the full voltage ranges and I'm not going to reset it back just to find out). You can dial these voltage settings right down to 6 volts and as high as 28 volts in spite of the absolute maximum voltage rating figure being only 26 volts. Of course, with this unit currently being mains powered, this function remains disabled.

 This capability to use rechargeable battery packs of any chemistry without undue risk of reverse charged cell damage from over-discharging the battery is a very handy feature of the control module and you might think the 12.6 volts from a freshly charged car battery would provide too little power into an 8 ohm heating element (I've got a 16/18 watt Antex that would suggest otherwise) but for soldering low thermal mass joints, it's actually more than sufficient if you can tolerate the more protracted warm up time.

 Going by its behaviour in seemingly avoiding 100% power other than for very brief bursts once you go over the 450 degree setting (who needs a 450 deg setting anyway?), I suspect the PID control algorithm has been designed to eliminate the risk of the heating element/thermocouple burning out. These direct drive tips with their 8 ohm heating elements may take 72 watts off a 24 volt supply but I suspect they wouldn't survive this treatment for very long. It seems to me more a figure of merit with regard to accelerated heating up performance and response to thermally demanding solder joints.

 The choice of a 24.5 volt smpsu over a 21 vot smpsu seems to have been made purely to create impressively quick heating up times with scant regard to stability. Looked at more closely, I suspect a simple voltage reducing mod to the existing smpsu board to drop the voltage will become all the rage with these soldering stations (once I've figured out where to solder in the extra resistor, whether a fixed or switched option - perhaps using an internal jumper  >:D).

 I might reduce its existing "getting up to temperature" performance from "Hell! That was bloody fast!" to just "That was quick!" but I'd expect much better temperature control at the lower voltage. Reducing the heating power from 72 down to 52 watts won't impact its soldering performance very much when the "at 450 deg temperature" power input is being throttled back to just 20% of the full 72 watt rating of the tip anyway.

 The wattage figures quoted by the big brand named manufacturers for their direct drive tips are almost certainly attention grabbing headline figures anyway so I think exploring the lower voltage options will lead to a better balance between performance and usability.
 
The burn-in. I agree it sounds like the KSGER possibly does a more aggressive compensation for an inherent con of the T12 tips (the sensor is directly coupled to the heater; not desirable). Might have to test it.

 The heating element is made with nichrome (chromel) which is one of the metal alloys used to construct a K type thermocouple so all that is required to turn the heating element circuit into a K type thermocouple is to use alumel as the return conductor. Unfortunately, the 41μV per K difference between the hot and cold junctions is not produced at the hot junction but is the result of the imbalance of the thermoelectric effect along each conductor as a result of the different metal alloys used for each of the two wires which connect the hot and cold junctions.

 This means that the voltage produced will essentially be an indicator of the heating element temperature rather than what is happening right at the hot junction by the tip. For more info, you can do what I did (Cheat - I'm no thermocouple genius!) and look at the wikipedia article here:- https://en.wikipedia.org/wiki/Thermocouple#Type_K

 Cunningly disguising your thermocouple as a heating element might seem undesirable but perhaps not quite for the reasons you might have thought. As long as you can afford to shut off the heating current for long enough to sample the thermocouple voltage (the 8 ohm resistance in one leg of the circuit won't matter when detecting a voltage with a relatively high impedance circuit - in this case 10KR or higher should be high enough), say a millisecond or two every 100 to 200 or more milliseconds, there shouldn't be any problem monitoring heater/tip temperature this way other than for the inconvenient fact that it is the temperature of the heating element rather than that of the actual business end of the tip that's being monitored in the pious hope that, through the high thermal conductivity of the metal used to conduct this heat  the actual tip temperature won't be lagging too far behind. ::)

[The above statement in regard of the thermocouple only measuring the heater temperatures is actually a misconception on my part - Apologies for this and please check out my explanation in the edit at the end of this article]

 If you read the whole of that wikipedia article, you'll see mention of the ageing effect which means our cartridge tips will eventually start to under-report their temperature, causing them to run a little hotter as a result of the controller trying to maintain the reported temperature. The calibration feature is more than just "A nice touch", it's more a necessity if you don't want to eventually end up frying your delicates (smds).

 As for the required accuracy, it's just as well that there's some considerable leaway in soldering temperatures. The choice of just sufficient temperature with a longer dwell time versus the higher temperature with a shorter dwell time to avoid overheating the components is a "Damned if you do, damned if you don't." kind of choice. Low temperature reduces oxidisation and flux boil off rates but risks higher component temperatures whilst "Hot 'n' Quick" risks burnt tips and flash boiled flux if the task is fumbled. The experienced solderer soon adapts to the best balance between these two extremes - thankfully there's a lot of latitude to work within.

 Talking of accuracy (and referring back to a comment I made earlier), I bought a cheap clone of the Hakko FG-100 tip thermometer to allow me to calibrate my collection of T12 tips. Since the original Hakko and clones alike all use a K type thermocouple with its characteristic 41μV per K output, a cheap clone tip thermometer needn't be any less accurate than an over-priced Hakko 'original' (at least in principle) but I'm having some doubts as to how it (or even whether it) implements some form of 'cold junction compensation'. Since it's a clone of the Hakko unit, it does beg the question as to whether genuine Hakkos will behave in exactly the same way as mine did.

 Mine, a Daniu branded clone, seems to track the room temperature to within a tenth or two of a degree of my weather station's ambient temperature readings (and that of the KSGER's cold end temperature in sleep mode which was calibrated to the weather station's reading to begin with - just an extra data point).

 On the face of it, it would seem to have some form of cold junction compensation but when I took it outside to see if it would match (or at least track) my outside thermometers and weather station's remote sensor, I saw some rather wild variations of temperature (ranging some 5 to 10 degrees higher than expected) which bore no obvious linkage to the outside conditions. Next, I thought I'd see just how cold our chest freezer really was. Incredibly, it never registered below zero deg C other than to offer a fleeting glimpse of the minus sign on a zero deg reading.

 At that point I'd refitted the thermocouple the wrong way round, thinking it had some aversion to indicating temperatures below zero and then I started seeing the reading go up to 27 deg (minus, obviously) but when I took it out and allowed it to warm back up, instead of sticking on zero as it passed that point, it started showing minus readings before I decided to refit the thermocouple the right way round to make sure it would return to a sane ambient reading which it eventually did after warming it over the toaster to some 70 deg to accelerate evaporation of the condensation it had accumulated on being removed from the freezer.

 In spite of that abuse, it now reads the room temperature just as it did before, somehow giving the impression that it does have some form of cold junction compensation that works when it's sat on a bench in a room that varies from a low of 19 to a high of 24 deg C. If anyone is intrigued enough by these results to repeat any of my tests, would you be so kind as to please let me know what you find? :)

 What's bugging me the most about this is that I can't figure out any circuit configuration or limitation due to bad design that could account for all this weirdness. If anyone's got any ideas of their own on this, I'd appreciate any sort of insight that might clear up this mystery. Trying to second guess someone else's design mistakes when you can't reverse engineer just what they've done wrong can be an exercise in futility if you "Haven't seen it all." I only know how it's supposed to work, not how many inventive ways there may be to make it fail so weirdly.  :-//

JBG


[EDIT 13:25 BST 15 Sep 2019]

 Inspired by that wikipedia article and the exorbitant price of even the cheapest of replacement thermocouples for these soldering iron tip thermometers (they're a 'consumable' where  'cheapness rises to the top of the list of desirable 'properties'), I started looking for "DIY Thermocouple" articles during the reading of which, I suddenly had an epithany.

 Whilst it is true that the voltage produced between the hot and cold junctions is a consequence of the Seebeck effect over the whole length of the thermocouple wires joining the hot and cold junctions, this doesn't alter the fact that the voltage produced is still due to the difference in temperature between each of the junctions even when the conductors pass through a region at a higher temperature than the 'hot junction'. The reason of course, being that it's only the net temperature difference between the hot and the cold reference junctions that matters.

 Excursions of temperature along the wires joining the two junctions beyond that of each junction simply cancel themselves out in the net temperature difference equation that informs us of the temperature at the hot end junction compared to that at the cold end junction.

 What this means is that it remains possible to place our hot junction close to the 'business end' (perhaps right at the 'business end' by drilling a short gallery into the core of the copper bit into which the hot junction can be placed) and essentially ignore the higher temperature on the thermocouple wires obliged to pass through the much higher temperature region of the heating element.

 Of course, practical limitations in the placement of the hot junction means the effect of the thermal gradient between the heater and the tip will compromise the goal of sensing the tip's actual temperature to a greater or lesser extent depending on the details of the design of our self sensing direct drive cartridge tip. It's not too difficult to see where clone tips might fall short of the originals.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 14, 2019, 06:21:54 am
Quote
Cunningly disguising your thermocouple as a heating element might seem undesirable but perhaps not quite for the reasons you might have thought. As long as you can afford to shut off the heating current for long enough to sample the thermocouple voltage (the 8 ohm resistance in one leg of the circuit won't matter when detecting a voltage with a relatively high impedance circuit - in this case 10KR or higher should be high enough), say a millisecond or two every 100 to 200 or more milliseconds, there shouldn't be any problem monitoring heater/tip temperature this way other than for the inconvenient fact that it is the temperature of the heating element rather than that of the actual business end of the tip that's being monitored in the pious hope that, through the high thermal conductivity of the metal used to conduct this heat  the actual tip temperature won't be lagging too far behind. ::)
But there is a problem. When the heater is on, a temp gradient will develop between the heater/sensor and the copper slug at the base of the tip. The heater will reach higher temperatures than the surrounding copper ever will; and the sensor is directly coupled to the heater. So when the power is on full blast, and it is temporarily cut to take a reading, it will measure higher than when the heater has been off for longer and the temp of the sensor is actually closer to that of the surrounding copper. Despite the copper could be the same exact temp in either case.

In the 888, the sensor is thermally insulated from the heater. The sensor is measuring the temperature radiating from the inside of the tip. For the heater to affect the sensor, it has to heat the tip; then the tip heats the sensor.

Quote
that once a stabilised tip has been set to the maximum of 480 degrees, the percentage of power, after the initial burst of accelerated heating at 100% for the first second or so, it soon drops down long before it gets to within 50 degrees of the target temperature to just 15%.
Both my clones exhibit this behavior at all set temps. They throttle down well before reaching set temp and only slowly coast to full set temp WHEN UNDER NO THERMAL LOAD. When under load, they sag, significantly.* I believe it to be the natural side effect of the thermal coupling between sensor and heater. Maybe there are clones with more sophisticated sensor compensation.

*Yes, all irons exhibit temperature drop/gradient between the base of the tip where the sensor is and the point that is on the joint. But apples to apples, similar 3mm bevel tip on either, the T12 clones I have exhibit an additional sag compared to the lower power 888, which I suspect is due to the sensor/heater thermal coupling.

The "less overshoot" is bullshit on these clones. Any overshoot on an 888 is minimal. And when it does happen, it's temporary. The T12 clones have to be set to a significantly higher set temp to overcome the thermal sag, and they spend a lot of time at this significantly higher set temp while doing production type soldering. The overshoot of an 888 is much preferable to this situation. These T12 clones basically have way more "undershoot" than the overshoot of an 888.

The T12 clones (which I have) are excellent for a hobbyist that wants a fast warm up time and for anyone who needs to run such high temps anyhow that standby is essential. And cartridge tips are excellent for sustaining high load/output without warming up the handpiece. But they do not regulate better/tighter.

Quote
The heating element is made with nichrome (chromel)
Yeah, if you say so, I'll roll with it. W/e it is, it's just one of many stainless steel alloys that is used for heating wire. Like other stainless steels it is a poor conductor of heat compared to non-stainless steels/irons. And even cast iron is a poor conductor of heat compared to copper. Add the fact that the heater wire must be electrically insulated from the copper, and that it's tightly coiled up in a relatively small volume rather than spread throughout the copper,*** and that is why a rather significant temp gradient will occur when the heater is active. Heater gets hotter than the copper; sensor is directly connected to the heater; hence what the sensor measures is affected by other variable than just the temp of the copper at the base of the tip. Your signal has a skew to it, which is an interesting challenge to fix through software. It is especially interesting since the user of the iron represents an unknown, unpredictable variable to the thermal load on the tip, and that load will also increase the amount of sag in this loop. In addition to the sensor being connected/coupled to the heater and being affected by heater activity, the T12 heater needs to have a certain amount of mass to do its job, and the thermocouple needs a certain minimum mass to transmit the power without heating itself up. The ideal sensor for this, say like the one in an 888, would have a super high surface area to mass ratio, with very minimal mass, since it only needs to be a variable resistor to a very low voltage and current signal.

***I imagine the heater is a relatively small and compact length of coiled nichrome that is tucked into a hole in the back of the copper tip-slug with a dab of thermal cement, based on the price point these are made to.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: jadew on September 14, 2019, 09:37:37 am
Quote
that once a stabilised tip has been set to the maximum of 480 degrees, the percentage of power, after the initial burst of accelerated heating at 100% for the first second or so, it soon drops down long before it gets to within 50 degrees of the target temperature to just 15%.
Both my clones exhibit this behavior at all set temps. They throttle down well before reaching set temp and only slowly coast to full set temp WHEN UNDER NO THERMAL LOAD. When under load, they sag, significantly.* I believe it to be the natural side effect of the thermal coupling between sensor and heater. Maybe there are clones with more sophisticated sensor compensation.

That is standard behaviour for any PID controller that's correctly tuned, and should behave roughly the same with or without a load. The 888 should behave similarly, with the added downside that because of the thermal lag, it will have poor transient response. It will be both slower to get to temp and it will have more overshoot when removing the load, as well as taking more time to figure out it's loosing temperature when applying a load.

No matter how you look at it, delay in a PID controller is bad and it will yield poorer results.

Edit: Generally speaking, when you have lag in the response you have to compromise between slow and overshoot. The smaller the lag is, the smaller the compromise.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 14, 2019, 09:48:38 am
Quote
That is standard behaviour for any PID controller that's correctly tuned,
It is beyond that, though.
edit: If you sink heat out of the tip, the base of the tip will also sag in temperature, not just the pointy end. The circuit only powers the heater with a small portion of the available duty cycle. It has bumped the power some, but not as much as it should. The base of the tip sags in temperature from the set point, and the circuit doesn't do anything to amend this problem. It accepts it. This is the new normal/equilibrium.

Quote
and should behave roughly the same with or without a load.

You are not speaking anything I can make sense of. I have explained already in the previous post. T12 sensor/heater has mass. Tip under load means it is something is sinking heat out of it. Copper transmits that quickly. But it takes a bit for the sensor to change, because it has lower heat conductivity and has some significant mass. 888 is superior in this regard.

Quote
The 888 should behave similarly,
But it does not. The heater is switched by a triac, and there is no PWM. There is an indicator LED (7 segment decimal point) that lights up when the heater is switched on. (And it is accurate; scoped it some 2-3 years ago; when the dot is lit, the heater is receiving full power). The 888 does not behave like this, and anyone who owns one can easily attest. It doesn't need to, because the thermal mass of the tip is large enough, the power is low enough, and the sensor response is exceptionally fast by design. There is additionally no lag in the heating. That is not a weak link; there's no shortage of electricity to make more heat. So what if the 888 heater must (very quickly) reach higher temp:surface area to drive same wattage into the tip as the T12 heater? The only weak link of the 888 is the leakage of heat into the rest of the handpiece.

Quote
with the added downside that because of the thermal lag, it will have poor transient response. It will be both slower to get to temp and it will have more overshoot when removing the load, as well as taking more time to figure out it's loosing temperature when applying a load.
I will agree to disagree. :-//

Edit: A really good PID should be able to give closer to all or nothing on the gas when it's still tens of degrees off. The better performing PID would give 100%, shut off power, completely, and coast up to the correct temp, and then resume the exact right itty bitty duty cycle to keep it right there just as it is peaking. It wouldn't start going 30% or less when it's still 50C low. And it wouldn't allow a greater thermal load to result in a falsely high temp reading, triggering sag.

Quote
Edit: Generally speaking, when you have lag in the response you have to compromise between slow and overshoot. The smaller the lag is, the smaller the compromise.
You assume the 888 sensor significantly lags behind when the tip changes temp, and that this is a weak point in the system. What makes you think that? You make assertions without showing how you got there.

If you drill a hole into a copper block and insert a temp sensor, then stuff some asbestos insulation to plug the hole, the temp of that sensor is going to stay very close to the temp of the copper block no matter what you do.  Put that block in your oven and turn it on, and your sensor will faithfully report the temperature of the block of copper. There will be a little lag, due to thermal mass of the sensor and heat conductivity/transfer. But if you designed it right, it is going to be fine and not any concern compared to the rate of delta you can expect for the block in your application. That's a hakko 888.

Now instead of putting it in an oven, take the heater coil out of your oven and crumple it up into a ball, and stick it in the hole with the sensor. Turn on the "oven" and warm the block up to 300F. Your sensor got fried to a crisp in the interim, because the heater reached, say, over 1100F in order to do this. And after you turn it off, that coil remains hotter for a discrete amount of time, due to its thermal mass. So given you can read the temp of the sensor, now figure out how hot is the copper block... How to do that conversion? Well, you can try to make some sort of correction based on past history leading up to this point, but that reading is simply inaccurate at first. And it gains in meaning the longer you let the heater cool and gain equilibrium to the surrounding copper.




One of my T12 clones has no microcontroller. The control circuit is fairly simple. There's a 1 shot that powers the heater, and there's a comparator that fires this one shot. When the comparator says go, heater is powered for a spell. After that set amount of time, it returns to sensing and waiting for the sensor to drop in temp enough to trigger the next dose of on-time. The natural result is that the power is pretty close to 100% only for the first 5 seconds when first turning the station on. Once it has gotten in the neighborhood of set temp, you will never get the heater over a 50% duty cycle again, even if you dunk the tip in a glass of water. The delay before retriggering starts to grow well before the tip reaches temp, since the heater is reaching higher temp than set temp by this point. This has nothing to do with fancy PID. It's just a dual opamp circuit.

So the temp rapidly rises at first. But it slows down way too early. And it limps to the set point with the duty cycles ever decreasing. When you apply a heatsink to the tip to siphon off some wattage, the duty cycle creeps back up just a little. The circuit happily allows sag and stabilizes at a lower temp of the base of the tip. The circuit simply waits for the temperature of that sensor to drop to X (as set by the knob) before it fires the next dose, and because of the discrete amount of time it takes for the sensor to cool back down from just being roasted, there is your lag. The T12 setup is the one with the lag.

Even under no-load equilibrium at full set temp, where the heater is on a low duty cycle just to maintain temp in ambient air, the sensor data includes an offset for the differential between (hotter) sensor and (cooler) base-of-tip. When under increasing sink from contact with a joint, this point will get reached prematurely, because the differential between the sensor and the base-of-tip has gotten larger by way of higher duty cycle to the heater AND faster cooling of the tip by the heatsink. Both of these things increase the error in the reading. So the offset for the set-point at no-load is no longer big enough to correct for the current conditions.

Going from undertemp joint to the next, the recovery is also throttled back to a crawl for no reason other than artifact of heater/sensor design. It is a temp controlled station, but the temperature control is compromised and partially hamstrung.

My other T12 "Bakon" has an AVR microcontroller. It might have fancy PID, but it performed just as poorly (actually a bit worse) in controlled test with temperature probe regarding sag.

The thermal lag in an 888 causes it to oscillate in a sawtooth, once it reaches equilibrium. In a T12 clone, this sawtooth is almost completely gone. But it means the temp stabilizes at ever lower sag point under load, much greater drop and problem in practice than the sawtooth of the 888 in equilibrium. This is in the T12 clones I have; maybe yours has 200% more magic beans. And even of the ones I have, for some persons for some purposes, the advantages will be enough to not care about this area of absolutely worse performance. For me, the advantages of the T12 cartridge are not enough, and I still await the knowledge of which T12 clone (or genuine 951, for that matter) has the magic bean PID that can better correct for the sensor/heater compromise without creating new compromises.

It is very easy and straightforward to comparison test the amount of sag from set point between irons, using an iron temperature tester and a test PCB. No need to theorize and guess based on your own (possibly incomplete; I'm not exempting myself, mind you) understanding of thermodynamics and marketing wankery and shoulda woulda coulda. All you have to do is test it. It's not subjective. It doesn't matter why one performs better than the other. You don't have to understand or reason it through, even if you're capable. All you have to do is test it, because in the end we are talking about the performance of a soldering iron.

And at least put some eyeballs on it (e.g. you could scope your T12 clone's output FET to see its behavior*) and process it for a second, before you declare "this" to be "standard behaviour for any PID controller that's correctly tuned." It is fairly obvious that if you compare this to standard thermostatic behavior, or to optimized PID, this is neither one nor the other, nor is it anywhere between; it's clearly on the wrong side of what you would call an "improvement." If this behavior is created, intentionally, it's the result of a series of terrible decisions...

... or maybe you would find that your T12 station does not perform the way I have described mine.

*it might help to either fiddle with the timebase of your scope to make it slow enough to plot pwm as an average voltage and/or to connect an R-C low pass filter and measure the voltage on the capacitor, if all you have is a DMM.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 16, 2019, 01:08:06 am
Quote
Cunningly disguising your thermocouple as a heating element might seem undesirable but perhaps not quite for the reasons you might have thought. As long as you can afford to shut off the heating current for long enough to sample the thermocouple voltage (the 8 ohm resistance in one leg of the circuit won't matter when detecting a voltage with a relatively high impedance circuit - in this case 10KR or higher should be high enough), say a millisecond or two every 100 to 200 or more milliseconds, there shouldn't be any problem monitoring heater/tip temperature this way other than for the inconvenient fact that it is the temperature of the heating element rather than that of the actual business end of the tip that's being monitored in the pious hope that, through the high thermal conductivity of the metal used to conduct this heat  the actual tip temperature won't be lagging too far behind. ::)

But there is a problem. When the heater is on, a temp gradient will develop between the heater/sensor and the copper slug at the base of the tip. The heater will reach higher temperatures than the surrounding copper ever will; and the sensor is directly coupled to the heater. So when the power is on full blast, and it is temporarily cut to take a reading, it will measure higher than when the heater has been off for longer and the temp of the sensor is actually closer to that of the surrounding copper. Despite the copper could be the same exact temp in either case.

In the 888, the sensor is thermally insulated from the heater. The sensor is measuring the temperature radiating from the inside of the tip. For the heater to affect the sensor, it has to heat the tip; then the tip heats the sensor.

Quote
that once a stabilised tip has been set to the maximum of 480 degrees, the percentage of power, after the initial burst of accelerated heating at 100% for the first second or so, it soon drops down long before it gets to within 50 degrees of the target temperature to just 15%.

Both my clones exhibit this behavior at all set temps. They throttle down well before reaching set temp and only slowly coast to full set temp WHEN UNDER NO THERMAL LOAD. When under load, they sag, significantly.* I believe it to be the natural side effect of the thermal coupling between sensor and heater. Maybe there are clones with more sophisticated sensor compensation.

*Yes, all irons exhibit temperature drop/gradient between the base of the tip where the sensor is and the point that is on the joint. But apples to apples, similar 3mm bevel tip on either, the T12 clones I have exhibit an additional sag compared to the lower power 888, which I suspect is due to the sensor/heater thermal coupling.

The "less overshoot" is bullshit on these clones. Any overshoot on an 888 is minimal. And when it does happen, it's temporary. The T12 clones have to be set to a significantly higher set temp to overcome the thermal sag, and they spend a lot of time at this significantly higher set temp while doing production type soldering. The overshoot of an 888 is much preferable to this situation. These T12 clones basically have way more "undershoot" than the overshoot of an 888.

The T12 clones (which I have) are excellent for a hobbyist that wants a fast warm up time and for anyone who needs to run such high temps anyhow that standby is essential. And cartridge tips are excellent for sustaining high load/output without warming up the handpiece. But they do not regulate better/tighter.

Quote
The heating element is made with nichrome (chromel)

Yeah, if you say so, I'll roll with it. W/e it is, it's just one of many stainless steel alloys that is used for heating wire. Like other stainless steels it is a poor conductor of heat compared to non-stainless steels/irons. And even cast iron is a poor conductor of heat compared to copper. Add the fact that the heater wire must be electrically insulated from the copper, and that it's tightly coiled up in a relatively small volume rather than spread throughout the copper,*** and that is why a rather significant temp gradient will occur when the heater is active. Heater gets hotter than the copper; sensor is directly connected to the heater; hence what the sensor measures is affected by other variable than just the temp of the copper at the base of the tip. Your signal has a skew to it, which is an interesting challenge to fix through software. It is especially interesting since the user of the iron represents an unknown, unpredictable variable to the thermal load on the tip, and that load will also increase the amount of sag in this loop. In addition to the sensor being connected/coupled to the heater and being affected by heater activity, the T12 heater needs to have a certain amount of mass to do its job, and the thermocouple needs a certain minimum mass to transmit the power without heating itself up. The ideal sensor for this, say like the one in an 888, would have a super high surface area to mass ratio, with very minimal mass, since it only needs to be a variable resistor to a very low voltage and current signal.

***I imagine the heater is a relatively small and compact length of coiled nichrome that is tucked into a hole in the back of the copper tip-slug with a dab of thermal cement, based on the price point these are made to.


 I'm a little ashamed to say that the posting you're responding to contained a major misconception on my part. I've since edited that post to correct this but I'll paste that edit here to clarify the situation.

[EDIT of Reply #52 13:25 BST 15 Sep 2019]

 Inspired by that wikipedia article and the exorbitant price of even the cheapest of replacement thermocouples for these soldering iron tip thermometers (they're a 'consumable' where  'cheapness rises to the top of the list of desirable 'properties'), I started looking for "DIY Thermocouple" articles during the reading of which, I suddenly had an epithany.

 Whilst it is true that the voltage produced between the hot and cold junctions is a consequence of the Seebeck effect over the whole length of the thermocouple wires joining the hot and cold junctions, this doesn't alter the fact that the voltage produced is still due to the difference in temperature between each of the junctions even when the conductors pass through a region at a higher temperature than the 'hot junction'. The reason of course, being that it's only the net temperature difference between the hot and the cold reference junctions that matters.

 Excursions of temperature along the wires joining the two junctions beyond that of each junction simply cancel themselves out in the net temperature difference equation that informs us of the temperature at the hot end junction compared to that at the cold end junction.

 What this means is that it remains possible to place our hot junction close to the 'business end' (perhaps right at the 'business end' by drilling a short gallery into the core of the copper bit into which the hot junction can be placed) and essentially ignore the higher temperature on the thermocouple wires obliged to pass through the much higher temperature region of the heating element.

 Of course, practical limitations in the placement of the hot junction means the effect of the thermal gradient between the heater and the tip will compromise the goal of sensing the tip's actual temperature to a greater or lesser extent depending on the details of the design of our self sensing direct drive cartridge tip. It's not too difficult to see where clone tips might fall short of the originals.
[/EDIT]

 You seemed in doubt about the use of nichrome (chromel which is one of the alloys used both in heating elements as well as one half of a K type thermocouple) for the heating element in the Hakko (and cloned) T12 cartridge tips but it makes perfect sense to choose this particular alloy since it then becomes a simple matter to convert it into a K type thermocouple by welding the top end connection close to or within the copper tip to its partner alloy, alumel, for the return conductor.

 Rather neatly, Hakko have created a dual function all in one heating element/K type thermocouple, where each function is just a matter of time sharing with a PID controller. My misconception of the thermocouple so formed only being able to read the heater element temperature simply doesn't apply. It is no less capable of sensing the hot end temperature than a thermocouple connected via a separate dedicated circuit to the controller (other than for some slight heat leakage along the chromel heating wire leading from the coiled chromel wire which makes up the bulk of the heating element - a factor also present to a lesser extent in the separate thermocouple case since its wires are likewise forced to pass through the heated region).

 No doubt, the PID control algorithms can be fine tuned in both cases to take account of this effect, leaving little to choose between the dedicated and dual function sensing options. In the end, it all comes down to the details of the cartridge tip design and that of the controllers and the sophistication of their PID control algorithms which, going by my own experience with the KSGER version 2.10 firmware, still has some way to go in its development.

 As for my idea of reducing the drive voltage by a few volts to tame the KSGER T12 controller's behaviour, I'm having second thoughts about expending any further time and energy in pursuing such a strategy. As I've already stated, I can't see much benefit in using temperatures above 350 deg C for soldering in general, particularly as I don't intend to use lead free solder in any of my projects.

 Since stability and performance seem perfectly ok in the more sane soldering temperature ranges below 350 deg, there seems little need to try a reduced voltage option. In any case, on those rare occasions where I might need more heat output to solder sheet metalwork such as creating shielding boxes from tin plate or copper clad board, I'm sure the controller will respond much better in those cases of heat demand when the tip has to be kept in contact with such heavy duty thermal sinks.

 Since I've never had experience with any soldering tools other than the half century old sleeve bit technological innovation made by Antex (now refined in the Hakko T12 cartridge tips) and just lately, a brief experience with the KSGER T12 soldering station, I see no point in arguing against your case for the Hakko 888 soldering station kit's superiority over that of the FX-951 and these cheap Chinese upstarts designed for use with T12 tips.

 However, we do seem to be in agreement regarding these KSGER T12 soldering stations being a very cost effective upgrade from the basic soldering iron when it comes to hobbyist use (ignoring the issues of electrical safety and poor workmanship in the assembly of the handles).

 Quite frankly, these cheap soldering stations based on the T12 tip technology represent a leap forward on a par with that of Antex's electrically heated sleeve bit technology over that of the old fashioned gas heated poker irons that preceded even the crappy electrically heated versions of those old fashioned poker irons (Solon Irons, anyone?).

 They may lack the level of power and temperature stability of professional kit designed for production soldering such as Pace and JBC but they more than make up for this with a rich feature set more suited to the hobbyist's typical 'hit and run' pattern of use, even outdoing the Hakko FX-951 soldering station in this respect (I watched the following review video to refresh my memory of the FX-951)

https://www.youtube.com/watch?v=YYZs_pewRd4 (https://www.youtube.com/watch?v=YYZs_pewRd4)

 It was a competently done review but I did notice a serious error in regard of the T15 (T12 tips for most of us purchasing via Ebay and Amazon) when showing the circuit of the tip connections. The two ring connections are the only connection to the heater/thermocouple circuit. The sleeve contact, which was shown as a common connection point for separate heater and thermocouple circuits, is totally isolated from the heater circuit, the function of which is solely to provide an ESD safety earth contact.

 After my experience of the KSGER soldering station, what struck me most about the FX-951 setup was it's needless complexity in sensing the idle time through the use of a 'special' soldering iron holder with its gravity operated micro-switch requiring all the paraphernalia of a stereo cabled link using 3.5mm jack and sockets at each end and a feature poor user interface requiring a pathetic plastic key to minimise interference with its "key settings" (pun unavoidable) by cow-orkers in a factory floor setting.

 I did notice that the startup timings from cold (and from the needlessly high 200 deg C standby temperature), though still respectfully fast, were a little bit more protracted than the KSGER unit's timings (but we all know the price of such speed - stability issues at temperatures above 350 deg C and the need to "deflower" virgin tips).

 Referring back to the question posed by this thread's title, I'm very much of the opinion that the KSGER T12 soldering station is a better alternative than going for an all original Hakko setup with it's needless complication, cumbersome UI and higher price even when purchased secondhand. This cheap Chinese alternative does have the virtue of being based on the Hakko T12 (T15) cartridge tips (whether fakes, KSGER clones or original Hakko) which provides a range of 85 or more tip shapes to suit every conceivable need (perceived or otherwise).

 The only major downsides that I can see with these cheap Chinese made units are the safety issues in the 24v smpsu boards used in most variants of this T12 soldering station and the quality of the workmanship in the handles, all of which are amenable to uncomplicated DIY re-working by almost every hobbyist blessed (or cursed) with even the most rudimentary of soldering skills. As such, I certainly couldn't recommend them as a first time soldering iron purchase to a novice electronics enthusiast going beyond the solderless breadboarding stage of their hobby for the very first time.

 However, I would recommend these soldering stations to anyone running a class in basic practical electronics as an excellent repair or (for the kit versions) build project for such novices to take away at the completion of the course. It could either be in the form of basic coursework materials stock paid for out of tuition fees or else at the top of a "recommended buys" list of self provided materials not to be plugged into a mains socket without the supervision of the tutor to verify that it would safe to do so.

 I know we should be discouraging such shoddy disregard for electrical safety (and to a less urgent extent, quality of assembly) by refusing such cheap Chinese death tr... bargains but this is the real world and there seems to be an inexhaustible supply of cash strapped hobbyists lacking the essential life skill often referred to as "Cynicism" (millennials) all too willing to part with their hard earned 'at any price', so that laudable "Refuse to buy" action just ain't gonna fly.

 The way I see it, such Chinese cheapies represent a way for me to monetise (in a round about way) my electronics skills by converting such danger ridden cheap and shoddy kit into cheap kit that I could otherwise not afford to own. In times past, I've used my skills merely to convert shoddy expensive kit into expensive kit worthy of its expense.

 This time round, the difference now, courtesy of China's disregard for electrical safety, is the added sense of danger you get when receiving such goods from the likes of Banggood and chums. Plugging such Chinese cheapies straight into a wall socket unchecked after unboxing them is a game I call "Chinese Roulette". It's similar to Russian Roulette only without the loud bang and smoke of a revolver and with much longer odds than the one in six chance of being the loser in the traditional game.

 Whilst the extruded aluminium cased KSGER T12 soldering stations all seem to be cursed by the dangerous smpsu board issue (the tatty plastic cased units seem to use a safer design of 24v 3A smpsu board) and the build quality of the handles supplied/available for this series of soldering stations is rather questionable, I don't see why this alone should deter anyone in this group, looking to satisfy a hobbyist usage requirement, from buying one.

 The faults are trivial to remedy by anyone with a modicum of DIY electronics repair skill in possession of a basic 25 watt soldering iron and a 180 watt or so rated soldering gun or equivalent (requirements which I believe should easily be met by almost everyone reading this sage advice of mine here  ;)  ). Suggesting that such defects are reason alone to recommend against its purchase to the membership of the eevblog forums would, I feel, be an insult to the group's intelligence, especially so for the ever resourceful hobbyist looking for a cost effective way to upgrade and expand their existing soldering toolkit.

 Mention of the "Cash strapped Hobbyist" case, it's possible to build one from the many parts available for even less money than I paid for my ready built unit. If you already have a 20 to 24 volt dc 3A rated power supply or a 4S to 6S liPo battery pack (with charger) to hand and a suitable enclosure to build it into, you can buy the 3 digit LED versions for as little as six or seven quid and save a ton of cash. I think the OLED versions were around the 18 quid mark the last time I looked

 However, having checked out Banggood, Ebay and Amazon, they don't appear to be quite so prolific as they once were and looking at what is available, I get the impression that this is older stock with all the "Good Stuff" having been hoovered up. I believe there were issues with these early versions burning out their analogue 3.3v regulator when powered from 24 volt supplies (the later models used a dc-dc converter to get round this issue) so this might not be quite as good an idea after all. In the end, it might be better simply to buy a ready built unit like this one https://www.banggood.com/KSGER-V2_1S-T12-Digital-Temperature-Controller-Soldering-Station-Soldering-Iron-Tips-T12-K-p-1338117.html?cur_warehouse=CN (https://www.banggood.com/KSGER-V2_1S-T12-Digital-Temperature-Controller-Soldering-Station-Soldering-Iron-Tips-T12-K-p-1338117.html?cur_warehouse=CN)  for which I paid £39.05 last month.

 It's currently at £38.39 right now (it had been dropped to just under 30 quid just over a week ago for maybe a whole week) so what its price might be in a few days time is anyone's guess. Internet shopping has never been easy at the best of times IME and Banggood's trampoline pricing doesn't make this task any easier. As far as I can see, that particular item still represents the best bang for the buck as well as the best combination of accessories, not just on Banggood but also everywhere else I've searched.

 These can be bought in kit form but they're often way more expensive this way. I even saw a kit of this model for 37 quid and some change that included everything except a PSU board!  :wtf: Also, if you're new to buying from Banggood make sure you don't pick the dearer warehouse option by force of the habit that the CN option is always cheaper. This isn't always the case as I found out to my cost when I ordered a Mustool G600 Digital 1-600X 3.6MP 4.3inch HD LCD Display microscope for a couple of quid more than the UK warehouse option price which would have also allowed me to take earlier delivery as opposed to my still having to wait for it to arrive a week after placing the order.

 If anyone is tempted to try out one these cheap soldering stations, good luck in securing one at the right price and don't forget to check out all those youtube review and teardown videos if you haven't already bingewatched them like a good boy scout (always be prepared!).

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 10:04:50 am
Quote
What this means is that it remains possible to place our hot junction close to the 'business end' (perhaps right at the 'business end' by drilling a short gallery into the core of the copper bit into which the hot junction can be placed) and essentially ignore the higher temperature on the thermocouple wires obliged to pass through the much higher temperature region of the heating element.
This is a nice idea. But even if you move the hot junction away from the main section of heater, the hot junction still needs to be large enough gauge to transmit power. And it still needs to be electrically insulated from the surrounding copper. So in otherwords, it takes up space. Space that could otherwise be filled in with copper. I think the front of the tip is better served to be solid copper than to hollow it out for this type of sensor.

I might have some spare tips to cut in half. Another day, perhaps.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 16, 2019, 06:17:18 pm
The Edsyn 971 (used) finally showed up today.  It seems ok.  I think it will be fine for my uses, although I definitely wouldn't buy one of these new at a $300 price for hobby use.

I like the pod iron holder.  It holds the iron well, and it opens up  to change out what looks like a wax paper insert for catching solder drips.

The iron feels ok.  The cable for the iron is about 40".  The iron is hardwired.  The tip that came with it is a small chisel tip, maybe 1.5MM, which will be good for my uses for now.

The station has a 'Heater Cycle' LED.  The way that it seems to work is that when no heating is taking place the LED is off.  When it is getting up to the set temp, the LED is solid.  When it begins regulating the temp, the LED flashes quickly.  And it seems that when it reaches full temp, the LED flashes slowly.

Using the temp probe on my DMM, it seems to take around a minute to to go from a beginning temp of 32C to a setting of 700F/371C, but the temp on my meter is showing around 350C at that point.  I'll have to play around with it a bit more to see if I can get better temp measurements from my meter and see how much the temp drops when doing big joints.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 06:26:25 pm
Quote
When it begins regulating the temp
It's always regulating temp from the moment you turn it on.  ;D
Quote
the LED flashes quickly
Curiously, the LED/heater of an 888 never flashes quickly. Idiots think this is necessarily an indication that this indicates delay in response compared to an iron that flashes nonstop. That is one theoretical explanation, but in this case it is because the 888 has an accurate sensor with a very high signal to noise ratio.

In case of the Edsyn having moments where it does this super fast/fuzzy blinking, I suspect some leakage/coupling between heater to the sensor, honestly, and/or more noise, less signal. Quick flashing is not necessarily indication of awesome, high tech stuff happening.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 16, 2019, 06:30:59 pm
Quote
When it begins regulating the temp
It's always regulating temp from the moment you turn it on.  ;D
Quote
the LED flashes quickly
Curiously, the LED/heater of an 888 never flashes quickly. Idiots think this is necessarily an indication that this indicates delay in response compared to an iron that flashes nonstop. That is one theoretical explanation, but in this case it is because the 888 has an accurate sensor with a very high signal to noise ratio.

In case of the Edsyn having moments where it does this, I suspect some leakage of heat from the heater to the sensor, honestly. Quick flashing is not necessarily indication of awesome stuff happening.

I played around with it a few times so far.  There is definitely quick flash and slow flash patterns, although I am not positive on what they mean.  The manual is very minimal in operation instructions.  It only says on the Heater Cycle LED:  Set desired temperature.  Blinking Lamp means Tool is regulating.  http://www.edsyn.com/mm5/graphics/00000001/971i.pdf (http://www.edsyn.com/mm5/graphics/00000001/971i.pdf)

Also of note here, I tried sending Edsyn an email to ask some questions on iron tips, but my email domain was bounced (Tutanota).  So if I want to talk to anyone about it, I will have to call.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 06:43:07 pm
Unless there is some indicating going on with the fast blink (not related to the heater action, but Edsyn wanted to add some visual indication of some state), I think the manual is just feeding marketing level wank.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 16, 2019, 06:48:00 pm
Quote
What this means is that it remains possible to place our hot junction close to the 'business end' (perhaps right at the 'business end' by drilling a short gallery into the core of the copper bit into which the hot junction can be placed) and essentially ignore the higher temperature on the thermocouple wires obliged to pass through the much higher temperature region of the heating element.
This is a nice idea. But even if you move the hot junction away from the main section of heater, the hot junction still needs to be large enough gauge to transmit power. And it still needs to be electrically insulated from the surrounding copper. So in otherwords, it takes up space. Space that could otherwise be filled in with copper. I think the front of the tip is better served to be solid copper than to hollow it out for this type of sensor.

I might have some spare tips to cut in half. Another day, perhaps.

 Damn it! You just spotted the snag in my thoughts on trying to place the thermocouple closer to the tip!  :(

 I have the feeling that I may be overthinking this issue of sensor/heater placement. Looking at the tip construction of the irons used by the Hakko 888D stations, it looks like the thermocouple must simply be embedded right at the end of the exposed ceramic heater element, presumably with a few millimetres separation from the end of the heater section so it seems these irons have a similar issue to the T12 cartridge tips regardless of whether the thermocouple is on its own circuit (perhaps sharing a common low resistance return wire).

 Practically speaking, there seems no obvious way to avoid sensing the temperature somewhere along the thermal gradient betwixt tip and heater (hopefully, a point closer to the tip than to the heater). I can imagine that a very sophisticated PID control algorithm could make allowances for this less than ideal situation, taking into account predetermined temperatures versus the averaged amount of power being delivered to the heater, it's effect on the thermal gradient, taking into account thermal lag and so on but it looks like a very complex solution that could still be knocked out of kilter by slightly unusual soldering conditions.

 Chaos theory looks likely to be The Lord Murphy's choice of weapon here in confounding the soldering station manufacturers' best efforts if they go for a complex PID control algorithm solution. Perhaps I'm overthinking things yet again. :-//

 I notice a lot is being made over the virtues of 'direct drive' versus the fixed heater with interchangeable sleeve tips setup. Undoubtedly, cartridge tips have an advantage but not because they offer better heat transfer from heater element into the tip than the older, Antex styled sleeve tips but mainly because they can concentrate the heat into a lower thermal mass tip for a faster response to the thermocouple sensor feedback to the controller. Reducing heat leakage back into the handle is a nice bonus feature but the basic 25W Antex isn't troubled by excess heat leakage into the handle but that has double the grip to tip distance of a T12 tip in a 9501 handle to solve this minor issue.

 The myth of "Better heat transfer" from the heating element into the sleeve tip is what irritates my sensibilities the most with this argument. The plain fact is that it doesn't matter whether the thermal gradient between the tip and heating element is 150 deg C or 250 deg C just as long as the nichrome wire used in these elements stays comfortably below its melting point which it obviously does as demonstrated by all those ancient Solon 65W monstrosities with their remote heating section glowing red hot just to get a screw retained tip at its far end up to a working temperature of maybe 350 deg C on a hot day (without a following wind if you're lucky).

 Sure, some extra heat energy will go the wrong way but it's just a case of "Give it a longer handle and bump the heat up another five percent or so." The thermal gradient between heater and tip is not the big deal it's made out to be. That in itself is not the great advantage for the direct drive cartridge tips.

 The major advantage is in getting the heat source closer to the business end of the tip and in reducing the non- working area to minimise the "Space Heater" effect of the bulkier designs. It also helps reduce co-lateral damage and aids visibility around the solder joints being worked on in the more cramped space of the miniature world of SMD circuit boards (so much so that you need magnifying aids to see exactly what you're doing with the end of your pencil tipped iron).

 Of course, the reduced thermal mass places more reliance on the PID temperature control algorithm providing adequate compensation against the heat sapping effects of soldering activity. In this regard, I agree with your own assessment that overshoot is a more desirable departure from perfection than undershoot with this form of soldering temperature regulation.

 With regard to the thermal conductivity of copper, the following youtube video is an impressive demonstration of this although I did cringe a little over the use of a two tine fork arrangement where I'd have formed each side of the thick copper wire 'desoldering bit' into triangles to provide two thermal paths into each end of the bases being applied to the IC's pins. https://www.youtube.com/watch?v=xMXJTLWyBCo (https://www.youtube.com/watch?v=xMXJTLWyBCo)

JBG

Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 16, 2019, 06:49:02 pm
Scatterandfocus, from what you described the LED is showing heating. Solid while warming up, fast flashing then slow flashing then off, it all fits the narrative.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 06:55:08 pm
Quote
I have the feeling that I may be overthinking this issue of sensor/heater placement. Looking at the tip construction of the irons used by the Hakko 888D stations, it looks like the thermocouple must simply be embedded right at the end of the exposed ceramic heater element, presumably with a few millimetres separation from the end of the heater section so it seems these irons have a similar issue to the T12 cartridge tips regardless of whether the thermocouple is on its own circuit (perhaps sharing a common low resistance return wire).
I disagree.

The sensor on an 888 is indeed at the tip of the ceramic stick. The heater is behind that. But this doesn't mean they are tightly coupled. The sensor and heater can be separated by thermal insulation/heat-shield. Maybe it's 3mm thick of insulation? Maybe it's less? It's still insulated way better than the T12 sensor. Provided there's sufficient insulation, the main thermal coupling between them besides the tip, itself, is the ceramic case and the air gap in the hole. The radiating heat from the inside of the tip can effectively swamp that out.

Take sensor; put it in a block of copper; plug the hole with asbestos. Now heat the block by shooting a torch right into the hole. The asbestos blocks that heat from transferring directly to the sensor.* It's the copper that the torch heats up. The copper distributes this heat very effectively. So the copper block acts like it's all the same temp. To heat up the area around the sensor, you have to heat the entire block.

edit: if you turn on an 888 with the tip off, the ceramic heater will glow and break (or maybe it is smart enough to detect a user error?). Because the sensor will never reach the set temp. When you remove the tip, you remove 99% of the thermal coupling.

If you removed the tip from the T12 heater/sensor and turned it on, it would cut back/kill the power sooner/earlier than normal.

*A good thermal insulator like asbestos basically can maintain a large temperature differential on either side of itself with minimal heat transfer/conduction. There's a limit. When that differential exceeds that amount, then the conduction occurs very quickly. Think of it as the VFD of a diode. As long as you are below the knee, conduction is minimal. When you exceed it by X, it's much like applying X directly across a good conductor. So the designer of this station just has to select the insulation and thickness that covers the worst case. This applies to the "horrible" air gap between heater and tip in an 888, as well. Someone who doesn't know physics might think this airgap necessitates a "lag" or "delay" in heat transmission. Once the differential is established (heater X degrees hotter than the air... Air is X degrees hotter than the copper...) the conduction occurs relatively unimpeded. There is no such "delay." What goes in one end comes out the other. If we also had to cool the tip from the heater end, then that would be a bigger problem. This stackup would cause slop in the lead screw when switching directions, and taking out that slack would require a discrete amount of time. But since we only have to heat it at one end, and 99.9% of the cooling (and only cooling) occurs at the other end, there is very little slop in the lead screw. And this is gone very soon after the heater turns on, and everything moves in lockstep.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: scatterandfocus on September 16, 2019, 06:56:48 pm
Unless there is some indicating going on with the fast blink (not related to the heater action, but Edsyn wanted to add some visual indication of some state), I think the manual is just feeding marketing level wank.

I just noticed that the flash pattern is variable, not 2 states.  The pattern seems to be fastest when getting up to temp and settles down to a slow pattern after reaching temp.  Sort of... It doesn't seem terribly well indicative of anything meaningful to me at this point.  I will treat the station like I treated the old Hakko 936 ESD.  Turn it on, wait a minute or so, tin the tip, and solder some joints.  And if I need to adjust the temp, twist the knob.  No menu fiddling.  What I am really curious about with this station is how well it will do for big joints, being that the heater is rated at 95 watts.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 07:18:02 pm
Quote
The pattern seems to be fastest when getting up to temp and settles down to a slow pattern after reaching temp.
Weird.

888 is solid on until it hits set temp. Then it quickly settles into a distinct duty cycle for w/e load it is under, like clockwork. At 300C no load, it is a short blip every 2-3 seconds, maybe 4-5% "duty cycle" (although the period is not exactly constant, it is very close to being a metronome). Under a constant heatsink of some size, the heater will quickly settle into a regular rhythm, at a higher "duty cycle," again, like a frigging metronome. Except the "period" shortens, as expected, due to a higher rate of change (cooling) of the tip.

This is exactly the behavior you should expect in a thermostatically controlled iron that is operating with clean, accurate, responsive sensor information. For the exacting repeatability/consistency that is observed (demonstrating relatively high accuracy), the response time of an 888 is actually very incredible.

Not referring to scatterandfocus Edsyn odd behavior. But in general, if your iron heater flickers on/off super fast, that is either PWM or noise in the sensor or heater/sensor coupling. If the tip is still miles off from set temp, it is more full power. When it gets closer, it doesn't know the fuck to do at any given time and is either averaging out to be right (if it's purely noise) or it is sucking (if there is also underlying unresovlable error, say due to coupling). There is no way that it is representative of a "super fast response time," considering the size of the copper tip and the the power of the heater. That is wishful thinking and naievity. 

99% of people don't understand basic physics/thermodynamics enough to even apply known science and knowledge to a model like a soldering iron. Enter marketing wanketeers. They suggest stuff that "makes sense" to this average person. And that person says, "oh yeah, I knew that," and they automatically connect dots that don't connect. And forever more, they "know" stuff that is completely wrong. As long as the iron is soldering stuff 10 seconds after flipping the switch, they are completely happy and satisfied that all the other claims are 100% scientifically correct.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 16, 2019, 10:58:00 pm
Quote
I have the feeling that I may be overthinking this issue of sensor/heater placement. Looking at the tip construction of the irons used by the Hakko 888D stations, it looks like the thermocouple must simply be embedded right at the end of the exposed ceramic heater element, presumably with a few millimetres separation from the end of the heater section so it seems these irons have a similar issue to the T12 cartridge tips regardless of whether the thermocouple is on its own circuit (perhaps sharing a common low resistance return wire).
I disgree.

The sensor on an 888 is indeed at the tip of the ceramic stick. The heater is behind that. But this doesn't mean they are tightly coupled. The sensor and heater can be separated by thermal insulation/heat-shield. The only thermal coupling between them is the ceramic case and the air gap in the hole. The radiating heat from the inside of the tip can effectively swamp that out.

Take sensor put it in a block of copper plug the hole with asbestos. Now heat the block by shooting a torch right into the hole. The asbestos blocks that heat from transferring directly to the sensor. It's the copper that the torch heats up. The copper distributes this heat very effectively. So the copper block acts like it's all the same temp. To heat up the area around the sensor, you have to heat the entire block.

 Is there any reason then, why Hakko haven't used exactly the same method with their direct drive cartridge T12 and T15 tips (same tips, different market regions)? You say the irons used in the 888D system keep the heater and thermocouple circuits separate from each other as opposed to the T12 direct drive tip arrangement of making the heater act as a thermocouple on a time shared basis.

 I'm wondering whether the move to this combined heater and thermocouple two wire arrangement in the FX-951 system wasn't inspired by a need with the 888D to shut off the ac current to the heating element during thermocouple readings to eliminate interference to the thermocouple signal anyway - why use four (or at the very least, three) contacts when the cheaper option of just two will serve the purpose just as well?

 IIRC, the FX-951 still used 24vac via a triac switch to power the heating element so would be restricted in its timings (assuming a zero crossing thermostat switching algorithm) to the nearest half cycle of mains voltage (8.3333ms for 60Hz or 10ms for 50Hz) although it would be kinder to the transformer to choose whole cycle switching periods giving thermocouple measurement windows of time in multiples of 16.7 or 20 ms for the controller to grab its readings.

 Obviously, there'll be the new issue of self heating of the thermocouple junction from the heating current in this case which may require a longer refractory period than just a single cycle of mains voltage to reduce its impact. A tenth of a second may be sufficient to reduce this effect to a negligible enough level for the PID control algorithm to take this into account.

 The obvious downside is that the dropping of heating power five cycles at a time is going to bite into the power rating depending on how frequently the measurements need to be taken in order to maintain a satisfactory level of control. At the lower power demands required to stabilise tip temperature at, say, the 350 degree mark, a much longer refractory period can be used, say 900ms off with 100ms on (10% power), offering less self heating error for the controller to deal with.

 Higher temperatures will require shorter refractory periods, coupled with longer on periods, making the controller's task to achieve temperature stability much harder. I suspect this may well be the reason for the KSGER's high temperature behaviour and the apparent 470 deg "ceiling" on maximum tip temperature that I've witnessed so far.

 It could be that Hakko have addressed this self heating issue by using their own wire drawing machinery to manufacture their own heating coils where the last 10 or 15 mm going into the thermocouple junction is much thicker to create the best trade off against electrical self heating and the increased thermal conduction from the heater region of the wire which may explain and justify their much higher price compared to the fakes or clones lacking in such refinement.

 Investing in a genuine Hakko T15 tip may well prove worth while in being able to avoid the need to 'deflower' a virgin tip and enjoy better high temperature stability and performance. The only fly in this jar of ointment is the seemingly exorbitant price to run this experiment.

 BTW, I was being very specific about the T15 choice of tip simply because there's a reduced risk of being sold a fake tip if I take a chance on an Amazon/Ebay seller (Banggood's T12 tips are definitely fake or at best, KSGER clones) rather than play safe and order direct from Hakko or one of their accredited agents. For now, I'll see how I get on with the KSGER clone tips - the experience may make me only too happy to part with the money to get a genuine Hakko tip which is the best way, imo, to "pay extra" for "the real deal" (no nagging doubts about the need to spend big).

 Having just searched for a Hakko agent, the one and only uk agent I could find (I'm not going to give this Hakko agent any oxygen of publicity - you can do your own research) is asking £12.66 (+ vat = £15.19) for most of the more common T15 tips. You can pay a lot more for the more specialised tip options and for those that think the cheap FG-100 thermocouple thermometer for checking tip temperature was too cheap at just around the ten quid mark, you can always salve your conscience by spending some 186 quid (plus vat! :wtf:) on the 'real deal'. :-DD :-DD :-DD :-DD

 I have a very strong feeling it will be a very chilly day indeed in Hell before I buy a "Genuine Hakko" T12 or T15 tip. >:( >:( >:( >:(

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 16, 2019, 11:10:58 pm
Quote
I'm wondering whether the move to this combined heater and thermocouple two wire arrangement in the FX-951 system wasn't inspired by a need with the 888D to shut off the ac current to the heating element during thermocouple readings to eliminate interference to the thermocouple signal anyway - why use four (or at the very least, three) contacts when the cheaper option of just two will serve the purpose just as well?

No. The 888 doesn't do this. And it doesn't need to do this. It doesn't cut power to take a reading. When the heater is on, it's 100% on, and it doesn't turn off until the sensor reading indicates it should. There's a zero crossing detector, but it is only used to switch the TRIAC on. The sensing/comparing is occurring continuously, nonstop (but how often the micro reads this, who knows? Maybe it is only reading in sync with the zero cross? Either way it's neither here, nor there. It works whether the heater is on or off just the same). The T12 uses a compromised arrangement for production/cost reasons, alone, I imagine. Although you can make an argument that fewer contacts increases reliability, since you're sliding a cartridge into a holder and powering/sensing through spring contacts.

Just for clarity, I am not 100% sure it's impossible for another clone (or genuine 951) to get accurate temperature readngs without needing excessive off periods of the heater to do so. I can't imagine the way you would do it without getting so deep/complex that the occasional mis-identification of current state creates a terrible error. Once the micro goes down the wrong rabbit hole, how long before it figures out north is actually south and what are the consequences? But I'm sure things are possible which I can't imagine.

The more info the station has the better. The 951 does not identify different tips, AFAIK, and some other cartridge systems have a way to transmit that information, so the station has at least that much more solid info to work off of.

Quote
Higher temperatures will require shorter refractory periods, coupled with longer on periods, making the controller's task to achieve temperature stability much harder. I suspect this may well be the reason for the KSGER's high temperature behaviour and the apparent 470 deg "ceiling" on maximum tip temperature that I've witnessed so far.
Yes, I agree that the higher the duty cycle, and the higher the heatsinking (the differential between 470C and ambient air > 350C and ambient air) the trickier it would be to get accurate temperature sensing. But FWIW, Hakko has set the limit of the 951 at 480C. I don't know how high the KSGER interface goes, but if it works reasonably well to 470C, that seems like it should be plenty hot. If you're at that temp to make solder joints, precise temp control probably doesn't matter, so long as the tip doesn't misregulate so bad it burns itself up. Anywhere near this temp, and you're smoking flux like mad, you're oxidizing any exposed iron plating like mad, and you're just gonna lift the iron when you see the joint flow. I mean, at this temp, you know you're not using the right tool for the job, already. Anytime you are using the thing only ever at 10 and wishing there was an 11... damn what a waste of engineering to make the thing adjustable to begin with. You might not be using the tool the way the designer imagined.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 17, 2019, 03:46:47 am
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I'm wondering whether the move to this combined heater and thermocouple two wire arrangement in the FX-951 system wasn't inspired by a need with the 888D to shut off the ac current to the heating element during thermocouple readings to eliminate interference to the thermocouple signal anyway - why use four (or at the very least, three) contacts when the cheaper option of just two will serve the purpose just as well?

No. The 888 doesn't do this. And it doesn't need to do this. It doesn't cut power to take a reading. When the heater is on, it's 100% on, and it doesn't turn off until the sensor reading indicates it should. There's a zero crossing detector, but it is only used to switch the TRIAC on. The sensing/comparing is occurring continuously, nonstop (but how often the micro reads this, who knows? Maybe it is only reading in sync with the zero cross? Either way it's neither here, nor there. It works whether the heater is on or off just the same). The T12 uses a compromised arrangement for production/cost reasons, alone, I imagine. Although you can make an argument that fewer contacts increases reliability, since you're sliding a cartridge into a holder and powering/sensing through spring contacts.

 That's interesting. I came across a thread in the dangerous projects forum describing something similar from 2013. The OP had designed a controller for use with the T12 tips where he described the use of a powerfet to switch the 24vac on and off for controlling the heater power, synced to the zero crossings, turning it off half a millisecond before it hit zero and turning it back on half a millisecond after to create a thermocouple voltage sensing window less than 1ms wide every half second or so to keep track of the temperature even during the on periods of the duty cycling of the heater's power level as well as monitoring during the off periods.

[EDIT 2019/09/21] Here's the link to that dangerous project's page http://dangerousprototypes.com/forum/index.php?topic=5264.0 (http://dangerousprototypes.com/forum/index.php?topic=5264.0)

 My first thought when I read that was that this was way too fast to avoid the self heating issue of the thermocouple junction but it would seem not to be quite the issue I supposed it to be. Once again, I seem to be overthinking this (in public! :-[ ) Overthinking things is ok given enough 'overthinking' time for all the facts to finally fall into place before offering them to all and sundry to pick to pieces.

 I think the issues I'm conjuring up do exist, just not quite to the troublesome level in practice that I imagine them to be in theory. One way I can imagine that the issue of self heating can be minimised is by using some sort of crimp to join the wires together which provides a larger area for the copper core of the tip to dominate the temperature of the junction and act as a heatsink for any self heating effect of the heater wire that makes up one half of the thermocouple junction.

 The crimp can be any suitable alloy just as long as it can maintain its integrity as a crimp with a healthy temperature margin beyond the upper limit of the maximum temperatures expected to be measured since it has no effect on the working of the thermocouple even when it provides the only electrical link between the wires rather than just squash them into direct contact with each other (another wikipedia fact! ;)).
 

Just for clarity, I am not 100% sure it's impossible for another clone (or genuine 951) to get accurate temperature readngs without needing excessive off periods of the heater to do so. I can't imagine the way you would do it without getting so deep/complex that the occasional mis-identification of current state creates a terrible error. Once the micro goes down the wrong rabbit hole, how long before it figures out north is actually south and what are the consequences? But I'm sure things are possible which I can't imagine.

The more info the station has the better. The 951 does not identify different tips, AFAIK, and some other cartridge systems have a way to transmit that information, so the station has at least that much more solid info to work off of.

 Assuming that dangerous projects controller worked at all with just a half millisecond's pause to get a measurement, the need for several cycle's worth of delay would appear not to exist. BTW, the use of a powerfet instead of the more common triac was explained by the OP as providing the finer control that a triac just cannot provide. He needed to be able to switch off a half millisecond ahead of the zero crossing event and back on half a millisecond after to create a measuring window that would have a negligible effect on power delivery to the heater. A triac simply couldn't be controlled by the micro-controller to this fine a degree.
 

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Higher temperatures will require shorter refractory periods, coupled with longer on periods, making the controller's task to achieve temperature stability much harder. I suspect this may well be the reason for the KSGER's high temperature behaviour and the apparent 470 deg "ceiling" on maximum tip temperature that I've witnessed so far.
Yes, I agree that the higher the duty cycle, and the higher the heatsinking (the differential between 470C and ambient air > 350C and ambient air) the trickier it would be to get accurate temperature sensing. But FWIW, Hakko has set the limit of the 951 at 480C. I don't know how high the KSGER interface goes, but if it works reasonably well to 470C, that seems like it should be plenty hot. If you're at that temp to make solder joints, precise temp control probably doesn't matter, so long as the tip doesn't misregulate so bad it burns itself up. Anywhere near this temp, and you're smoking flux like mad, you're oxidizing any exposed iron plating like mad, and you're just gonna lift the iron when you see the joint flow. I mean, at this temp, you know you're not using the right tool for the job, already.

 Those KSGER and its copycats have the same 480 deg C limit. However, you can exceed this using the boost function. In my case, I've got the boost delta set to 50 deg for one minute which raises the target temperature to 530 deg which so far it has fallen far short of achieving, managing only to get to 477 deg as measured with my cheap Hakko FG-100 clone thermometer.

 I haven't bothered testing what happens if I set a 100 deg boost delta but I imagine it will obligingly show a target of 580 deg and not get the tip temperature much if any higher. In any case, the tip is oxidised enough as it is already from this extreme abuse and that of the calibration procedure which includes a 450 deg test point.

 Just to satisfy curiosity, I set the boost to a delta of 100 deg, set it for 480 deg, let it stabilise (which it now does quite quickly) and gave the knob the quick three or more clicks to the right to activate the boost and saw the expected 580 deg target temperature come up on the display.

 I didn't linger very long as I watched it failing to stabilise before giving the knob a quick leftward twist to cancel the boost, after which I set it back to 300 deg before giving it another quick leftward twist to enter the 150 deg standby mode and another such twist to put it into sleep mode from where the only way to wake it up is to push the knob to bring it back up to the set temperature.

 In sleep mode it displays the date and time, the "POFF" status and the tip and handle temps until the screen saver kicks in (it's an oled screen) by walking a display of the 'cold end' temperature in square brackets, with the word "sleeping" above, around the confines of the display to remind you that it is still powered up, effectively turning it into an expensive room thermometer.

 TBH, I really can't see any need to have a set temperature higher than 400 deg C anyway and that only to provide some margin for calibration error in high heat demand situations which, in the case of the KSGER unit with its boost function that can be set anywhere from 10 to 100 degrees, becomes a surplus requirement. I certainly wouldn't want to set it any higher than 350 deg C but I suppose it's handy to know you can perform life accelerated tests on your collection of fake or clone T12 tips on a whim. >:D

 I'm afraid to say that I still haven't tried the soldering station out 'in anger' for lack of room on my work table due to the collection of stuff, retrieved from my basement shack and workshop that had fallen into a state of neglect these past twenty years, to assemble my current GPSDO project which has ground to a halt whilst I upgrade my soldering facilities. I'm still waiting on a magnifying visor which I purchased as a backup to the Mustek microscope I'm also still waiting on taking delivery of from Banggood, along with some other soldering related goodies.

 I seem to be suffering a severe case of "AJRPS" (Arnold Judas Rimmer Procrastination Syndrome for Red Dwarf fans) in that I keep turning to my desktop computer to scour the internet for video reviews on soldering stations and smd workstation microscopes with LCD screens and 30v 10A bench supplies and other stuff I've bought from Bangood, not forgetting my activities here.

 However, today, I may have broken the deadlock by buying a couple of "Small Parts Organiser" drawers from our local Lidl store which I'd spotted just by chance whilst accompanying the XYL on a visit to our local library just across the road from the store, the walk to which was on account the XYL was after a bath seat and some odds and ends.

 As is normal when you don't park in the store's car park, you land up with a trolleyful of shopping that can't easily be carried in a couple of shopping bags (we could have managed ok except for my purchases), so I had to make the short walk back to the car to drive round to the store's car park to collect the XYL and the shopping.

 Anyhow, I digress. The important thing is that I now have the means to 'organise' my collection of parts into a less space consuming configuration that will allow me to clear enough space to not only allow me to resume my project but also to let me return my DSO to its rightful place alongside my cheap signal generator that's currently buried beneath the clutter, keeping its OCXO nicely warmed up.

 That purchase had been earlier yesterday afternoon and it's now 4 am and I still haven't removed the shrink wrap to check them out let alone actually put them to use. The bench clutter remains untouched which is why I think I've got a serious case of AJRPS. :( The problem is that when I returned with my prizes and parked them on the floor to eye up the mess on my bench, I realised it was going to be a bigger job to sort out than I'd envisioned when I bought those small parts drawers, thinking it would be "A quick Fix" so I did just what our fictional hero was famous for and sat down at my computer to 'mull the problem over'.

 I guess (hope, really) that it'll all look different after a good night's sleep when I have another look at the situation later this afternoon. There's some twenty years worth of computer related detritus gathered up on the rear half of this large desk to be sorted out as well which had rather dampened my enthusiasm to get stuck into the task when I'd returned with those parts drawers. With luck, I may have formed a stronger opinion of my KSGER soldering station by the end of this week.  :-DD :-DD :-DD

JBG

Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 17, 2019, 05:20:15 am
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Assuming that dangerous projects controller worked at all with just a half millisecond's pause to get a measurement, the need for several cycle's worth of delay would appear not to exist.
Oh, I'm sure if he says so, he got readings. (I'm assuming he had to use back to back FETs in an SSR configuration).

The problem persists that the reading he gets will contain error, and it will not remain consistent just because he doesn't need to turn off the heater to get it. Depending on how long that heater has been on since it was last switched and depending on how much heat is being sinked out, it will change the error on the reading. It's cool he did that, but for many of us on the forum, this is child's play. Getting in, grabbing the tea leaves, and getting out... that's an afternoon of dicking around with a scope and microcontroller coding. I'd be much more interested to see the PID algorithm that can take this mess of tea leaves and come up with an accurate temperature reading. And to learn how you even start to tackle this kind of problem.




Looking at it from a God's eye view, it appears like a simple problem. Just turn it up when it sags. How hard is that? But looking at this as a programmer, the data you are working with is a sow's ear. You're in the middle of the Pacific with a broken compass. To get your true bearing, you have to go off course. And by the time you're back in the area you want to be, you are back to reading tea leaves.

Marketing: Awesome! Heats up in 10 seconds!

Management: Great!

Engineer: yeah, but OTOH...

Marketing: We eliminated overshoot!

Engineer: Well, technically the iron actually...

Marketing: We have a Boost Mode!* This is gonna be perfect on the brochure.

Management: Great job, guys. 

But, hey, I'm no math wiz. Maybe there's some elegant algorithm that does more than put a polish on this turd.

*Universal Truth: anything called Boost Mode is crap. And not everything can be fixed by software, even when the software guy is promising it. I'm being bugged by a client right now because a software guy has him convinced the impossible is possible. 1 second after reading his proposed solution, I responded with the reason why this won't work. I'm on my third email re-explaining it. I'm sure he will finally figure it out after convincing my client to fund the project, about 2 days before his delivery date, and then he will have new promises that will require just a tad more time and money.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 18, 2019, 05:31:32 am
Here's a youtube 'tutorial' by John Salt that attempts to describe how TS100 Soldering Iron Cartridge Tips Work. https://www.youtube.com/watch?v=vLT7L8NlUhg (https://www.youtube.com/watch?v=vLT7L8NlUhg)

 Unfortunately, in his mini-blowtorch heating test, he mistook the one millivolt per ohm reading of his DMM from the thermocouple/heating element for an actual change in resistance, jumping to the totally fallacious conclusion that the huge apparent drop in resistance was the means by which the controller sensed tip temperature.

 Perhaps if he'd been just a little more curious than he claimed to be and had kept applying the heat for just a few seconds more to see just how low an ohms reading he could get (it actually dropped to 0.4 ohms before it started increasing again), he may even have seen a negative resistance reading and finally correctly put two and two together and switch his DMM to the 200mV scale to unearth the fact that it uses a thermocouple in series with the heater element exactly like the system used by the Hakko T12 (T15) direct drive cartridge tips.

 Knowing as I do that heating element wire alloys are chosen not just for having a high enough melting point but also for having a very low temperature coefficient of resistance, it was blindingly obvious to me (as it should have been to John), that this wasn't a superstrong negative temperature coefficient of resistance sure to guarantee instant and destructive thermal runaway but some other phenomenon at work - the obvious contender being a thermovoltaic one, as in a thermocouple.

 It had struck me that the classic method of testing resistance with your typical DMM is that it simply to sets the voltage range to the lowest possible, typically 200mV and passes a constant current through the unknown resistance connected to its test leads which will translate directly to an ohms or K ohms or M ohms reading (1mA for the first two and 1μA for the 2 and 20MR with perhaps even 100pA for a 200M ohms range).

 I reckon his DMM must have been using a 1mA test current on its ohms range and, just fortuitously, was being applied counter to the emf polarity of the thermocouple in the tip. If he'd connected his DMM the other way round, he'd have seen an apparent increase in resistance with the applied heat and be even more readily fooled (I'd have still been suspicious and changed to the mV scale anyway).

 When I repeated this test for myself, I only had a simple gas lighter able only to produce a cooler yellow flame. Even so, I did manage to heat the K tip sufficiently to melt my 60/40 multicore solder which produced a mere 5mV from the thermocouple after I'd tried measuring the 'change in resistance' for each polarity of DMM connection which had shown me the expected decreased and increased readings with temperature rise.

 Anyway, aside from this shameful example of "scientific investigation", the thing I got out of this video was the fact that a much regarded soldering iron, the TS100, uses exactly the same "thermocouple in series with the heating element" principle as the T12 (T15) Hakko direct drive cartridge tips use.

 I hadn't previously taken too much notice of the TS100 oft mentioned in comparisons with the KSGER T12 soldering stations until now so was rather surprised to find that it's actually Chinese through and through. I was even more surprised to discover the relatively high prices commanded for replacement T100 tips (around the ten to thirteen quid mark, some three to four times the price of the Hakko T12 clones but around half the price of genuine Hakko T12 tips).

 The cold ends of the TS100 and the T12 tips look so identical, I'm surprised I couldn't find a TS100 compatible soldering handle for the KSGER T12 soldering station and its copycats (I did look! ;)). However, I did come across a couple of 3D printed adaptors to allow the cheaper clone T12 tips to be used in a TS100 handle. Presumably, the quality difference must be sufficiently small, possibly non-existent, for such adaptor projects to be worth doing just to shave 60 to 75 percent off the price of replacement tips.

 I think I'll stick with the existing pack of cloned T12 tips for now and see how they behave with extended use before I start spending any of my hard earned on a genuine Hakko tip. There doesn't seem to be any problem over temperature control if you keep below the 350 deg setting which is how I intend to use them anyway.

 It may not tick all the boxes in an industrial usage setting but this KSGER station should serve my hobbyist level requirements far better than my collection of basic Antex soldering irons, as fine as they are compared to others in this class of "plug into the mains and hope they get hot enough but not too hot" soldering irons in common use by many hobbyists thus far. I guess many of these basic soldering irons are soon destined for retirement after one last gasp use in fettling these cheap Chinese T12 soldering stations into serviceable and safe to use soldering station setups.  :)

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 18, 2019, 06:34:17 am
I was sitting here watching the vid, and it brought back memories. Of burning up the first T12 tip I had in about the first 30 seconds with a bench PSU and alligator clips. And then....

Holy cow. When he showed the thing warming up on the O-scope I had to rewind. That thing responds great!!! Not the speed, but how the power looks (best I can tell; unfortunate, that there's jitter that throws off the analog scope) near full all the way to set temp and how it jacks to near full when cooled with the sponge. My T12 clones are junk! (I only wonder why he is testing at 200C, not something more applicable?)  Now I'm really curious how this thing works. It's bugging me. All you have is one crappy sensor, and a micro to log power delivery and sensor readings over time, and somehow that looks pretty damn tight. The power delivery looks aggressive, at least. I wonder about regulation and sag at soldering temp. Variation at set temp can probably be found in datasheet/marketing info. But sag?

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Perhaps if he'd been just a little more curious than he claimed to be and had kept applying the heat for just a few seconds more to see just how low an ohms reading he could get (it actually dropped to 0.4 ohms before it started increasing again),
This brings back a memory. I made an iron controller years ago, using a PIC and an LCD. I had a cheap station at the time, and I just wanted this controller to drive this iron. I made the same mistake of measuring the resistance, thinking it had a thermistor. In fact, it was a thermocouple. But I had already plotted out the resistance over at least a score of different temps by the time I figured that out.  :-DD And... 

I got the thing sorted. Couple of opamps in series to amplify the thermocouple signal to the PIC. The firmware for the controls was done. And I said what the heck. I just used the resistance data I had recorded rather than re-doing voltage measurements. I just offset the ADC reading so that it was calibrated to a single measured temp of the lookup table, at 300C (or maybe the melting point of solder..). And it worked great. W/e the scale/curve, it was close enough across the board from min to max temp, 200-450Cish. I never tweaked a thing. But then I wasn't really too picky. It's just a number, and that's not the most important thing. I mean, it regulated fine, the range covered what I wanted, and making it more accurate to the numbers on the LCD wouldn't have made it perform any better.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Shock on September 18, 2019, 09:53:55 am
In that video he says "keeping the tip absolutely at the right set temperature". Yet the display is magically sitting on 200C the whole time and no tip measurement was actually taken to prove this.

I'll break it down for you. There is a large variance between the tip temp and display temp and the lag between them. So while it's displaying 200C/390F the tip could actually be still at 100C/210F. When it reaches actual stable temp regulation (as opposed to what the display says) the tip can still be as much as 30C/85F low. Obviously there is different firmware to correct the issues but it makes performance worse not better. The other thing is, if anything this is lower mass than a standard T12 tip.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 18, 2019, 04:55:25 pm
In that video he says "keeping the tip absolutely at the right set temperature". Yet the display is magically sitting on 200C the whole time and no tip measurement was actually taken to prove this.

I'll break it down for you. There is a large variance between the tip temp and display temp and the lag between them. So while it's displaying 200C/390F the tip could actually be still at 100C/210F. When it reaches actual stable temp regulation (as opposed to what the display says) the tip can still be as much as 30C/85F low. Obviously there is different firmware to correct the issues but it makes performance worse not better. The other thing is, if anything this is lower mass than a standard T12 tip.

 With this sensing technique, it seems to me that there'll be very little difficulty in accurately sensing the thermocouple voltage (it's a very low impedance source, in this case dominated by the eight ohm series resistance of the heating element). Although the circuit is only shielded by the ESD earthed tip, leaving about a metre of unshielded silicone insulated cable betwixt thermocouple and opamp input, the eight ohms impedance kills off any electric field interference effects leaving only magnetic induction to worry about.

 In the case of far off sources of magnetic field interference, say a mains transformer more than a couple of inches away, the close coupled return conductor will effectively cancel out any such induced voltages anyway, leaving only induction from adjacent wires in the cable to worry about. Since the one and only major source of such interference, the heater current, is shut off during these brief measurement periods, even this isn't an issue.

 The main issue in this case being the heat pollution from the heater section of our thermocouple circuit and the modicum of self heating of the nichrome wire leading into the thermocouple junction itself. If they've used a relatively large thermal mass crimp to create the hot end junction of this thermocouple, that could allow its temperature to be dominated by the heat from the tip itself, swamping out any heat leakage along the heater wire and that caused by self heating.

 It's not the perfect way to sense tip temperature from a thermocouple but as long as it's within 20 degrees of the tip rather than 20 degrees of the heater section, a lovingly crafted PID algorithm should be able calculate (more accurately 'guess') the actual tip temperature sufficiently well enough to be within acceptance for practical use in controlling tip temperature.

 Considering that the older alternative use of an electrically isolated thermocouple sensor circuit doesn't escape the effects of heat pollution from the heater either, the accuracy of this new system could well be better, given a clever enough PID algorithm and an improved design of direct drive cartridge tip.

 Given that, for reasons of practical limitations, the tip temperature can only be assessed from sensing on the hot side of the tip rather than the contact point with the workpiece, having a modest amount of overshoot is far more preferable to having a perfect ramp up to temperature with no overshoot and even more preferable again than a response that has any undershoot whatsoever.

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 18, 2019, 09:04:30 pm
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In that video he says "keeping the tip absolutely at the right set temperature". Yet the display is magically sitting on 200C the whole time and no tip measurement was actually taken to prove this.
Did he? LOL. Right you are, on all points.

I stopped listening to him by that point and was just watching the scope. 

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If they've used a relatively large thermal mass crimp to create the hot end junction of this thermocouple, that could allow its temperature to be dominated by the heat from the tip itself
Theory sounds ok to me. Except yeah, the crimp/heatsink would ideally be large in surface area and high thermal conduction/cross-section, but it should have low thermal mass as possible. Temp gradient will build at electrical insulation between this crimp/heatsink and the rest of the tip in accordance with this mass, and you want the dog wagging the tail, not the tail trying to wag the dog. So the idea is chasing its own tail, a little? (too far? :) )Dunno what material does that, and then there's still the mass of the end of that thermocouple and heat conducted to/through it from the heater.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 21, 2019, 10:54:59 pm
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In that video he says "keeping the tip absolutely at the right set temperature". Yet the display is magically sitting on 200C the whole time and no tip measurement was actually taken to prove this.
Did he? LOL. Right you are, on all points.

I stopped listening to him by that point and was just watching the scope. 

Quote
If they've used a relatively large thermal mass crimp to create the hot end junction of this thermocouple, that could allow its temperature to be dominated by the heat from the tip itself
Theory sounds ok to me. Except yeah, the crimp/heatsink would ideally be large in surface area and high thermal conduction/cross-section, but it should have low thermal mass as possible. Temp gradient will build at electrical insulation between this crimp/heatsink and the rest of the tip in accordance with this mass, and you want the dog wagging the tail, not the tail trying to wag the dog. So the idea is chasing its own tail, a little? (too far? :) )Dunno what material does that, and then there's still the mass of the end of that thermocouple and heat conducted to/through it from the heater.

 It wasn't a scientifically rigorous investigation was it? The scope evidence, whilst not so elegant a display as you'd see on a modern DSO with all of its fancy triggering features, did reveal the varying duty cycle of the controller in response to the heatsinking effect of the damp sponge just the same.

 As for the "Tail wagging the dog" expression, it wasn't 'too far' at all. In this case, it's not so much "A dog with two tails" as more a case of "A tail with two dogs". As long as our measuring point is closer to the dog of interest (the tip) than the other, less interesting dog (the heating element), we're in with a chance of measuring what the 'interesting dog' is doing to a reasonable level of accuracy.

 I was searching for any articles referencing the clone T12 tips versus the Hakko originals topic when I came across that dangerous prototypes forum again here, which, if you haven't already done so, I think you may be interested in reading :

http://dangerousprototypes.com/forum/index.php?topic=5264.0 (http://dangerousprototypes.com/forum/index.php?topic=5264.0)

 The use of a 24vac supply to the tip heater does have the merit of allowing continuous monitoring of the thermocouple voltage at the rate of 100 or 120 samples per second and, perhaps more importantly, the minimum of galvanic corrosion due to residual moisture and interference to the thermocouple voltage from any such stray galvanically generated potentials (assuming the power is PWMed in whole cycles of the ac supply).

 DC power tends to create a runaway effect on any such aqueous chemical reactions until, with sufficient heating, the moisture is eventually driven out to halt or reverse this process. It does occur to me that this 'burning in' requirement may simply be a reflection of a galvanic effect from residual moisture which may be at higher levels in the clones and fakes than in the more carefully fabricated Hakko tips.

 Otoh, it could be an effect only apparent in these T12 soldering stations such as the KSGER unit and its various copycats with their use of a 24vdc drive in place of the 24vac used in the Hakko soldering stations and its clones with the effect not being exclusive to the fake and clone tips. Using genuine Hakko tips might get you better quality but it won't necessarily be free of this 'burning in' effect seen with these DC powered T12 soldering stations. It's just a thought and it could all be just more bollix from yours truly. :-//

 The plain fact is, I haven't been able to unearth any definitive tests between fake/clone tips and genuine Hakko T12/T15 tips in regard of this 'burning in' phenomena observed with the KSGER T12 controllers so I'm left to hypothesise about possible/plausible mechanisms (the Devil makes work for idle hands - in this case, my need to better understand what's actually going on).

 I can certainly imagine the clone tip manufacturers leaving out the final drying out phase that Hakko take care to include in their own manufacturing of these tips. It may simply be a matter of leaving this final finishing phase as an end user instigated 'burn in' phase - just a minor inconvenience for the end user to deal with as far as the clone tip manufacturers are concerned (after all, it's just the 'price' the cash strapped hobbyist end user will be prepared to pay for such 'cheapness').

 In view of the ageing phenomena of thermocouples in general, the tip calibration feature is an 'essential' in all of these soldering stations simply as a means of overcoming the reducing sensitivity with age of the built in thermocouple in these direct drive cartridge tips regardless of brand.

 The KSGER oled display T12 stations have a more complex calibration process than the cheaper 3 digit led display versions, involving as it does, test temperatures of 450, 350 and 250 deg C. In view of the linearity of K type thermocouples and its close cousins over this range of soldering temperatures, this seems unnecessarily complicated a procedure. One can only hope that this extra complexity confers an actual benefit beyond allowing the controller to average out operator measurement errors.

 Although I haven't had as much experience using the KSGER soldering station as I'd have liked by now, it does seem to offer more for hobbyist use than a genuine Hakko FX-951 based setup. At least you still have the option to use genuine Hakko T12/T15 soldering tips if you feel the clone tips are a letdown in some way.

 Mind you, I think it's still worth investing a little less than the cost of a single Hakko tip in a 'starter pack' of ten assorted clone tips if only to get a better idea as to which two or three hakko tip types would best suit your needs, starting with just a single Hakko tip to verify that you'll actually experience a tangible benefit before investing another 50 or 60 quid in another couple of  Hakko tips (they're bloody expensive here in the UK!).

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 21, 2019, 11:22:28 pm
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It wasn't a scientifically rigorous investigation was it? The scope evidence, whilst not so elegant a display as you'd see on a modern DSO with all of its fancy triggering features, did reveal the varying duty cycle of the controller in response to the heatsinking effect of the damp sponge just the same.
Yeah, it seems to vary pretty sharply. But for all I know it's cutting back sharply to a very low duty cycle at X. And then under no load, the temp will slowly drift up 10-20C higher than X to a "soft" set point.* Then under a load it will sag to some varying degree in relation to the load.

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As for the "Tail wagging the dog" expression, it wasn't 'too far' at all. In this case, it's not so much "A dog with two tails" as more a case of "A tail with two dogs". As long as our measuring point is closer to the dog of interest (the tip) than the other, less interesting dog (the heating element), we're in with a chance of measuring what the 'interesting dog' is doing to a reasonable level of accuracy.
In this case, you'd be making a trade. To increase the thermal coupling to the tip, you're increasing the mass of the sensor. So now you're creating lag. It will be have less error so long as you give it time to stabilize, but it has to measure a moving target. So sometimes the error will be less, but sometimes it will be greater. And sometimes it might be error in the opposite direction, even.

The ideal sensor would approach zero mass, so that even though it is coupled to the tip through an imperfect conductor, even a slow amount of heat transfer will quickly bring the sensor closer to the temp of the tip. We don't need to overcome the "VFD" of the conductor/insulator that couples it. The little trickle of heat down to something approaching zero differential will keep it close enough for the job. Big dog easily wags small tail. Dog doesn't wag the 50 lb tail very effectively. For a thermocouple, for instance, the ideal shape would be a thin foil with a large surface area to maximize coupling to mass ratio. Perhaps a thin layer of metal vacuum deposited onto an insulator to plug up the hole in the middle with what acts like near zero additional thermal inertia once the insulator in the center finally gets to operating temp. (Yeah, I'm just making shit up at this point).

I said before that I don't know that it's impossible to correct this problem through software. It's just I can't figure out how it is possible. Average person might just assume someone smarter figure it out. I don't roll like that. If I can't figure out how it's done, I tend to believe it only when I see it. If you don't understand the stuff I wrote, it might be my fault.  I am not a physicist; and I'm a bad teacher; I assume you know some of this to understand what I'm saying. (And if you don't understand it, to you it's just one person's "belief system" vs another.) But I understand it; at least I think I do, and the people that come up with standardized aptitude testing also would guess I'm pretty good at this if their test works. What I have described was not some theory strung together to support a narrative. I have an understanding of the entire system start to finish (maybe I made some errors or have left some significant gaps; but AFAIK, my understanding is fairly complete and should be pretty accurate). Plus c/mon. The kicker is I tested it, and the results happen to support what I am describing. I agree though. If someone knows something but can't explain it to me, then I don't fully believe it until I see it. It's fine.

Now, even I don't trust my own bias. I made a conscious decision to use (one of) my T12 irons for a significant period, first. Ended up being 2 months, using is as my primary iron, to get some fuller/fairer sense of the perhaps not-so-obvious advantages and to see if any disadvantage would be noticeable/significant in practical use. It was two months later when I finally did the sag measurement/test. Maybe this sag is not as big a problem as I expect it might be, and if I measure/observe it, first, then I will be biased in evaluating if it makes a difference in performance. So I actually observed the performance con first, then verified it with testing.

One of the simplest tests with no room for subjectivity is the one I did in the thread 2 years ago. Compare two irons with a temp tester on the same heatsink. Adjust until they hold the same temp in this equilibrium. Take the iron away and let it stabilize under no load, and then measure the set temp under no load.

*I'm not suggesting this behavior, randomly. This is the behavior I directly attribute to heater/sensor coupling. This is what I expect to occur. If strictly working with current data with no memory, the circuit could not accurately tell the difference between one and the other. It doesn't know it is slowly drifting up to a no load set point. It doesn't know it's sagging under load. It doesn't know it cuts out too early when heating back up. To the circuit, it would all be "at set temp; all good; did my end of the job as best I can with the given information."
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 22, 2019, 01:43:00 am
Resolution.
Ok I forgot one thing. And that might have been due to personal bias. Resolution of the signal.

I previously stated:

Quote
If strictly working with current data with no memory, the circuit could not accurately tell the difference between one and the other. It doesn't know it is slowly drifting up to a no load set point. It doesn't know it's sagging under load. It doesn't know it cuts out too early when heating back up. To the circuit, it would all be "at set temp; all good; did my end of the job as best I can with the given information."

But to be fair, in conjunction with a second sample after a brief off time, you have essentially all the necessary data to calculate or cross check the tip temp. It's just you've got a graph SensorOutput over Time (since heater turned off), where the TrueTemp lines converge or nearly converge at Time = 0, and you're looking at a small slice of this graph right at this pinched up converging end. I made the mistake of thinking this was necessarily a problem. To resolve this you just need to... well, you need to be able to resolve it.  |O. It's so obvious in hindsight. If you have enough resolution, then what is the problem? In practice, you might end up with some unpleasant noise, but even if you did, you could probably average it out and still be fine.

So given enough resolution, and some minimal programmed algorithm involving some calculation and/or some simple lookup tables, I think you could overcome this. Is this the reason the Pace ADS uses a 17-bit ADC? When the heater shuts off, the temp drop would be relatively fast, so you would need a pretty substantial dynamic range to cover that slope. Add what you need to cover the entire temp range while heat is on and while off. And you'd have to still be able to resolve very small differences in the end points of your sensor temps, and even finer differences in the starting points. Seems like it would require a lot of resolution. And it would sure make sense for the display to simply read "low" until it gets at least up to 150C, so as to not waste any of it.

You might still also want to know how long the heater had been on for. That initial first X duration after switching heater state (near max duty cycle for that tip or near zero would be the only two states you would need) would have some differences. If this X duration significantly exceeds the sensor read period, then you would ideally want to account for it. With this plus the "high enough" resolution, you probably should be able to do it, but I'd have to chew on that for a bit to recognize the next thing I overlooked.
 
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 24, 2019, 05:28:28 pm
Resolution.
Ok I forgot one thing. And that might have been due to personal bias. Resolution of the signal.

I previously stated:

Quote
If strictly working with current data with no memory, the circuit could not accurately tell the difference between one and the other. It doesn't know it is slowly drifting up to a no load set point. It doesn't know it's sagging under load. It doesn't know it cuts out too early when heating back up. To the circuit, it would all be "at set temp; all good; did my end of the job as best I can with the given information."

But to be fair, in conjunction with a second sample after a brief off time, you have essentially all the necessary data to calculate or cross check the tip temp. It's just you've got a graph SensorOutput over Time (since heater turned off), where the TrueTemp lines converge or nearly converge at Time = 0, and you're looking at a small slice of this graph right at this pinched up converging end. I made the mistake of thinking this was necessarily a problem. To resolve this you just need to... well, you need to be able to resolve it.  |O. It's so obvious in hindsight. If you have enough resolution, then what is the problem? In practice, you might end up with some unpleasant noise, but even if you did, you could probably average it out and still be fine.

So given enough resolution, and some minimal programmed algorithm involving some calculation and/or some simple lookup tables, I think you could overcome this. Is this the reason the Pace ADS uses a 17-bit ADC? When the heater shuts off, the temp drop would be relatively fast, so you would need a pretty substantial dynamic range to cover that slope. Add what you need to cover the entire temp range while heat is on and while off. And you'd have to still be able to resolve very small differences in the end points of your sensor temps, and even finer differences in the starting points. Seems like it would require a lot of resolution. And it would sure make sense for the display to simply read "low" until it gets at least up to 150C, so as to not waste any of it.

You might still also want to know how long the heater had been on for. That initial first X duration after switching heater state (near max duty cycle for that tip or near zero would be the only two states you would need) would have some differences. If this X duration significantly exceeds the sensor read period, then you would ideally want to account for it. With this plus the "high enough" resolution, you probably should be able to do it, but I'd have to chew on that for a bit to recognize the next thing I overlooked.

 You do realise that in essence, you've just described a PID (Proportional-Integral-Derivative) controller algorithm.  :) see the wiki article here https://en.wikipedia.org/wiki/PID_controller

 I've always assumed that such control can overcome the imperfections in monitoring the tip temperature, given enough sophistication from a full understanding by the programmer of the many factors involved in such monitoring and control. The only 'unknown' in this case being the error between the thermocouple and the actual tip temperature due to manufacturing tolerances, making the need for a calibration routine of vital importance to obtain reasonable thermal control of the soldering process.

 One point I did pick up on from that dangerous prototypes thread, was the observation of the ~20μV per K thermocouple sensitivity used by the Hakko T12 tips (and, of necessity by the fake/clone tips for the sake of compatibility) instead of the 41μV per K of the classic K type thermocouple I had expected to see.

 It looks like Hakko may have chosen something similar to the N type TC simply to minimise the ageing effect typical of a K type. The observed sensitivity is less than the N type which was originally designed as a superior version of the K type so looks to be a proprietary combination of alloys chosen for low temperature coefficient in the wire used to form the heating element and minimal ageing effect. It's probably a lower sensitivity variant of the N type that lends itself well for use as a combined heating element and thermocouple.

 In this case there's no need to create a thermocouple to an industry standard μV per K sensitivity rating, just one that can provide sufficient sensitivity, capable of acting as a heating element. Indeed, it's in Hakko's best interests to use a proprietary thermocouple that best meets their needs with a minimal ageing characteristic. The soldering station can readily be calibrated to match whatever Hakko have chosen by way of the μV per K sensitivity of the built in thermocouple so doesn't represent an additional cost in its production.

 The KSGER's user mediated calibration feature is a rather neat way to address not only variations in clone and fake T12 tips but also that of the original Hakko T12/T15 tips as well as any errors within the controller itself. The default settings might put you in the ballpark with Hakko tips but even here, let alone in the case of the clones and fakes, it's worthwhile calibrating your collection of tips against a reasonably accurate K type thermocouple based tip thermometer such as those Hakko FG-100 clone thermometers which are no less accurate than the original Hakko units costing some 18 to 20 times as much. As long as you're within +/-10 deg C of the indicated temperature which you can fine tune anyway, you're good to go with most any soldering task you're likely to face in a hobbyist or semi-professional context.

 At the end of the day, the experienced solderer will adopt settings that best suit his working style and the nature of the soldering task that confronts him. The numbers on the soldering station merely represent a starting point of reference from which to fine tune for optimum performance anyway. Aside from this need to 'burn in' new tips when using the KSGER station, it seems to me a better alternative to the Hakko FX-951 station as far as the hobbyist/semi-professional user is concerned although I have to admit that I have little working experience to base that opinion on as yet.

 The issue with brand new tips may be nothing more than a need to drive out any residual moisture which can provide ionic conduction for the applied DC to create galvanic interference from the products of electrolysis so formed until all the moisture has been driven off to halt or reverse this undesired effect and it does occur to me that it might be worth rigging up a suitable 12.6vac or 15 vac 'conditioning' supply to drive out such moisture sans the DC bias voltage of the KSGER soldering station heater current.

 Since there is no such thing as a "failed experiment" (just an unproven theory - all experiments will tell you something useful, even if it's not what you'd hoped to discover), I'm looking forward to seeing the results (once I've located a suitable transformer). It might prove a better way to "Burn In" these T12 tips regardless of whether they're genuine or fake. Besides which, if such a heating cycle to drive out any residual moisture does work, it'll speed up the calibration process which, at a starting temperature of 450 deg C, will be no bad thing in terms of the needless tip oxidisation involved when I have no intention of subjecting them to such abuse in the first place.

 I had hoped to make a start in using the soldering station in ernest later today after finally taking delivery of a Mustool G600 LCD display microscope from Banggood earlier this afternoon but, unfortunately, the rear glass panel of its display was broken, either a manufacturing defect or shipping damage despite there being no other obvious signs of such. Thus I am further delayed in putting the soldering station to use and left awaiting a reply to my request for a full refund or a couriered exchange within the next ten days before I order from an ebay seller located in Ireland for a few quid more with a more realistic 3 to 10 day delivery time.

 At my time of life, I'm beginning to realise that I can't really afford the protracted delivery times of Banggood's cheap pricing, especially when what I've ordered, and waited so long for, arrives as 'broken goods'.  >:(

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 24, 2019, 07:00:43 pm
So you consider what I described as PID? Hmm, I guess I didn't think about it that way, because all this is just to figure out the current temperature of the tip. I suppose the temp of the tip is sorta the future temp of the sensor/heater in the moment you shut it off. So yes. But in this sense of the word, all this PID does is to make the iron able to perform like a regular iron, so far. Just to actually read the current temp of the tip. I suppose it makes much more sense now, thanks. I always wondered why people thought soldering irons needed PID, and maybe I was looking at it wrong. Some irons can't be improved with PID, but this one does damn well need it.. to read the tip temp.

So this requires a bit of resolution.

A regular iron need say 300C degrees of range (arbitrary here, lets say 180C to 480C). So it needs a resolution of about 300 in order to keep the iron to within 1 degree. Which is 8 or 9 bits of ADC resolution.
The T12 iron would need much more. How much more? Let's take a stab.

The floor would be the same for either. When heater is off for awhile, it will reach temp of the tip. So say at the bottom of your range around the 180C mark and under the right condition (say the user reduced the temperature setting, so the tip is drifting down to temp), the floor is the same. So let's go up 300 degrees and look at the ceiling.

At 480C, the regular iron, assuming it uses an ADC, needs that range of 300 to get there. The T12 would need that 300C degrees plus w/e the temp of the heater gets to beyond that. So let's add at least 100 degrees C, which is modest. Now we're up to a resolution of 400.

That's not so bad, we got that covered with 9 bits, still. Right? No, we don't.

The iron with the "easy" temp sensor is reading the temp. It needs to resolve down to 1 degree to know what the temp of the tip is to the nearest degree. The T12 iron needs to resolve a range of say 50C true temp tip that happens within a span of... who knows. But that won't stop be from guesstimating a few degrees. Free to add your own guess.

3C divided by 50C is 0.06C; Clarifitation: I'm saying that at the time the sensor is read, within some 100 milliseconds duration, difference of 3C at the sensor at that time would be a 50C difference in actual tip temp.  To know the tip of the temp to within 1 degree, the T12 ADC has to be able to resolve 0.06C changes. So in this guesstimation, it needs about 16.7x as much resolution, nominally. It needs a resolution of 6400, or about 13 bit ADC, at least.

Quote
As long as you're within +/-10 deg C of the indicated temperature which you can fine tune anyway, you're good to go with most any soldering task you're likely to face in a hobbyist or semi-professional context.
Mind you, this is not simply in order to be able to set the temp in 1 degree increments. It's so that the iron can tell the difference between degrees. What it can't resolve, it can't tell the difference. And then the sag comes back into play up to that unit of resolution. If the station is off in calibration, I don't care. If it can only be set to 5C increments, that's fine, no problem. If the unit sags 5C more than the other, then that kinda sucks, IMO.

I think with a 12 bit ADC and very optimized it might be possible to get within 2 degrees, if lucky. But that is if my guesses are close and everything works out conveniently sorting into the boxes we want to stick them in, and if my 100 degree overheat for the heater is enough. 12 bit is still borderline, with my guesswork. Pulled directly out of the rear, obviously. But real measurements could be done and this estimate could be done using real numbers.

I would guess Pace uses 17bit ADC because each of those bits is useful. (Or maybe they got a good deal). So to heck with completely guessing. Short of doing these experiments and measurements, I would err towards "Pace probably figured it out, already." To get your iron to regulate as tight as the Pace, I would bet you need most of those 17 bits. And I don't know any of this. I've never seen an ADS in person. I have only read some other user's observations and posts.

Just guessing in the dark, here. Nothing to see.

Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 25, 2019, 12:20:42 am
 You may be overthinking this. :)

 I was thinking that this could probably be done with a modern cmos Z80 cpu, say one clocked at a modest 8MHz. 8 bit unsigned integer could cover the range 150 to 400 deg C where you'd assume an overflow (carry result) to simply indicate "Too bloody hot! Cut heater power, buddy!" and a zero would indicate too low a temperature to solder with. You could equate each integer value (0 to 255) to 2 deg C (a one degree C accuracy is way more than we actually need - 5 deg C increments would be accurate enough for this task) which is enough to go from 100 to 610 deg C.  :)

 Even for the original 2MHz clocked Z80, a millisecond time interval is sufficient to carry out over a hundred instructions (provided not too many stack ops are involved) and the rate of change in temperature is unlikely to top half a deg C per millisecond. I'm not claiming to be up to the job of coding a sophisticated PID algorithm in Z80 assembler, just guessing that a basic control algorithm could be cobbled together for even a 2MHz Z80.

 However, with that thought in mind, I began to wonder about the STM32 controller actually used in these KSGER soldering stations so made my way over to the wikipedia article on STM32 controllers here:

 https://en.wikipedia.org/wiki/STM32 (https://en.wikipedia.org/wiki/STM32)

 My, oh my, there's a shitload to choose from isn't there?  ::)

 I still wasn't too keen to open up my own KSGER unit so undismayed, I searched with "which stm32 is in a KSGER" and found this fascinating EEVBlog thread, started by floobydust back in June (last entry being 16 July - fresh by my standards :)) :

 https://www.eevblog.com/forum/reviews/t12-stm32-v2-1s-soldering-station-controller-schematic-etc/ (https://www.eevblog.com/forum/reviews/t12-stm32-v2-1s-soldering-station-controller-schematic-etc/)

 It's only one page long at the moment but looks ready to tip over to a second page. I think you might find it an interesting read. >:D

 Drat that "Pandora's Box" thread! It looks like I will have to open mine up, after all ::)

 I wasn't particularly interested on the OSS aspect, more about the hardware issues, most of which I had already dealt with, including (just for the sake of tidiness) soldering the rotary controller tags to suppress possible ESD issues (assuming the TPHs actually connect to the ground plane - something else for me to check ::)).

 Incidentally, after downloading the reverse engineered schematic, I was rather startled to see the rotary encoder's pulse outputs represented by mechanical switch symbols but, after checking out the Bournes datasheet pdf on these encoders, it turns out that this is exactly how it's done  :wtf: Just two mechanical switches phased to produce overlapping square wave pulses just like you'd see with a simple optical encoder to drive a JK flipflop to synthesise a direction of rotation signal as in a tape footage counter (sans the needless expense (and the accuracy compromising effect) of a rubber belt drive... Akai you blithering idiots! - sorry for the mini :rant: - it's just something about Akai's flagship GX747 tape deck that's been bugging me for more than three decades since I discovered such blithering idiocy of design).

 I noticed a reference to a Hakko patent on this combined thermocouple and heating element tip cartridge direct drive design which, to my great surprise has now expired as of yesterday :wtf:

 Interestingly, they used a 24volt rectified, unsmoothed AC to power the tip to minimise the transient voltages you'd otherwise suffer by interrupting a smoothed 24v DC supply as per these KSGER stations. It seems they missed a trick in minimising electrolytic corrosion due to residual moisture issues by not rectifying the ac voltage - perhaps they do precondition their T12/T15 tips on a 12vac supply after all as part of the final bake out/quality control testing which the clone tip manufacturers don't bother with, preferring to leave all that to the hapless end user.

The moral of this being if you're going to use fake Hakko tips buy them in some quantity that equates to the cost of a single genuine Hakko tip, say a pack of ten or more. >:D That way, you won't be cursed by the "Sample of only one" effect in regard of the faulty/poor quality tip statistics figures. Well, it's a choice! ::)

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 25, 2019, 01:53:08 am
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I was thinking that this could probably be done with a modern cmos Z80 cpu, say one clocked at a modest 8MHz. 8 bit unsigned integer could cover the range 150 to 400 deg C where you'd assume an overflow (carry result) to simply indicate "Too bloody hot! Cut heater power, buddy!" and a zero would indicate too low a temperature to solder with.
Quote
You could equate each integer value (0 to 255) to 2 deg C (a one degree C accuracy is way more than we actually need - 5 deg C increments would be accurate enough for this task)
which is enough to go from 100 to 610 deg C.  :)

Yes, you can get 256 resolution from a byte, and that is plenty. AFTER you figure out the temperature of the tip. To do that within 2 degree accuracy will require WAY MORE resolution than 8 bits, because the data you are getting this from will have a huge temp swing from min to max, but the differences of heater/sensor temp (within a short enough period of time after turning off the heater to be practical) between say 300C while the iron is "floating" and 250C while floating will be very very small compared that very huge range you have to cover. That difference will not be 50 degrees at the sensor at Tmeasure. It will be a tiny fraction of 50C.* This is what you need the high resolution for. The temp of the heater/sensor rounds off to "really hot and barely relatable to tip temp" until you dissect it into very small bites (at least, best case is 25 smaller bites) to end up with actual 2C temperature resolution for the actual tip temperature.

So you need only a resolution of 25? No, you have to still cover the min max of the entire temp range, heater on or off. You have to cover that entire range with this high resolution net. But I said the sensor will be "hot" and differences are very small, so why the big range? Well, you also have to be able to measure temp when the heater has been off for awhile, say after reducing temp setting and it is falling. And there, the min just went low, real low.

I'm sure STM has 12bit ADC at least.

All of the stuff described from my "resolution post" would be done JUST to derive the actual tip temperature. That is all step 1. This is just to uncouple the sensor data from the heater.

*On second thought that might be a bad example. After reaching equilibrium that might be close to 50C. Here's a better example. The user is pressing the tip against the board, sinking out heat. This drops the temp of the base of the tip around the sensor. If you recorded at only 1 time after cutting off the heater, the reading will hit the set temp while the base is still below set temp. Because the differential between heater temp and tip temp will grow in that imperfect coupling between the two. So the actual tip temp will be lower than the station thinks it is. According to the single measurement, you're at the set temp; station will allow this sag. To correct for this problem is one of the reasons you need to take a second temp reading a discrete amount of time later. Here, the temperature of the sensor will be very slightly lower due to faster heat transfer vs the one floating at actual correct set temp. This is how you get rid of the sag, and why you need such a high resolution.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 25, 2019, 06:14:07 pm
This is why you need relatively high resolution.

This graph diplays temperature of the sensor over time, with T0 being when the heater is shut off.

In these two plots, one is under no thermal load. The other is while under a high thermal load.
In either case, the heater has been full duty cycle long enough to reach equilibrium. In either case, the temp of the tip is rising, but all the slack has been taken out of the thermal couplings by this time (and that's another thing the station/micro has to keep track of). It's just that at this particular time of sensor test, they happen to both have the same temp at the first reading near to T0. By resolving the tiny difference at Tmeasure, you can tell the true temp of the tip (or the future temp of the sensor).

The longer the heater is off, the closer it will get to the temp of the tip. But we don't want to wait that long.* If the temp is determined to still be under set temp, the heater is going back on at Tmeasure. The station won't get to see the rest of this graph. It makes the decision at Tmeasure.

This is why it needs relatively high resolution. The difference between tip temp of these two plots might be tens of degrees C (the two dotted horizontal lines are true tip temp). The difference could be, say, 50C under a very high load. But the difference in temp of the sensor at Tmeasure between the two could be a single degree. That single degree has to be resolved in (at least) 25 pieces to get 2C resolution of tip temperature. That's if those bites work out to near 2C all the way through that range, which it will probably not. That might result in 1C increments at one end of the range and 4C increments at the other. So you probably need at least double that resolution, say 0.02C increments of sensor temp to get 2C increments, and this would still include massive "pixelation." These are just made up numbers to illustrate the point, but you see the more resolution you have, the better your accuracy will be across the entire range. Pace ADS. 17 bit ADC. Starting to make sense, yet?

For the sake of simplicity, the true temp of the tip is considered static. Of course it will also start to drop at some point shortly after T0. But compared to the rate of change of sensor temp between T0 and Tmeasure, I think it's ok to ignore that across the time frame of interest. In this case the tip is the dog, and the heater/sensor is the tail.
 
*You want probably want multiple senses per second to be really responsive. Say you want a leisurely 10 reads per second. This makes each period 100ms. During the read, the heater is off. So if you wanted to be able to maintain at least 50% duty cycle (most T12 clones seem to reach higher), then the max your Tmeasure can be is 50ms. At 90% duty cycles, 10 times per second, the max your Tmeasure can be is 10ms. So we're at 10 samples per second, right now, and how much faster do you think you can get it? An analog iron with a proper sensor setup has an infinite sample rate. So much for the "faster response time" T12 fanboi argument. :) The higher the sample frequency you want to attain, the shorter Tmeasure. And the more ADC resolution you will need. Clock stability is also critical. This should benefit appreciably from an external crystal clock. If your clone runs on an internal ceramic resonator and uses a 12 bit ADC... meh. i don't think this is gonna be very accurate and responsive, if it attempts to correct for this error/sag, at all.

(https://i.imgur.com/49g93O7.jpg?1)
The top dotted line is the true temperature of the tip under no load (or load of ambient air, to be exact).
The bottom dotted line is the true temperature of same/similar tip under a heavy load.
The reason the sensor is at the same temp approaching T0 is because a differential between the temp of the heater/sensor and copper develops under load. The greater the heatsink/load on the tip, the greater this differential will get. This is the source of the error, resulting in sag/droop, if you do not correct it. This represents, say, the maximum amount of error you might need to correct. The "worst case" scenario. Beyond that amount, the heater wouldn't be able to keep up, anyway, and will be pegged on full in either case, with or without correction.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on September 26, 2019, 11:48:26 pm
 Apologies for the delay in replying. Quite apart from the need to chew over what you were saying, "Real Life" concerns had also intruded into my thoughts. I'm not talking about the more mundane RL concerns of the great unwashed you understand, more those of the, nevertheless still mundane, concerns of dealing with the results of shopping (on line - is there any other form of shopping for those of us now stuck between a rock and a hard place when it comes to buying electronic components and such like items?). I won't go into details here but, if you're interested, I've added them as a footnote[1] for you to peruse at your leisure. I've little doubt that I'm merely adding to the shared experience of the collective so make of it what you will. ::)

 My thoughts about using a Z80 cpu and 8 bit ADC data were more a vague 'thought experiment" to give the use of the much better endowed and orders of magnitude faster STM32 micro controller actually used in these KSGER soldering stations some context.

 I do see the point you're making about using higher resolution data from the tip sensor ADC in being able to more swiftly detect changes around the inflection points of the temperature curves in order to more precisely spot the trends and initiate the correct response in a more timely fashion to minimise the effect of lag.

 I suspect being able to differentiate between temperatures separated by only 0.02 deg C is likely to be thwarted by noise in the signal which will need to be filtered out (in the digital domain rather than at the analogue input stage).

 Luckily, most of this noise will be relatively high frequency and a low bandwidth of, say, 500Hz or less would likely serve our needs quite nicely in this application. Plenty of time for an STM32 to do the necessary DSP sufficient to perhaps resolve to within half a degree's worth of accuracy which I feel may well be 'overkill' even in this case.

 However, like you, I don't have access to any hard data to back up such an opinion. You could well be right in assuming Pace have a valid justification for the use of a 17 bit ADC in their very expensive soldering station kit.

 Inspired by that other EEVBlog thread (the OP actually), I soldered an earth strap between the TPHs used by the encoder's mounting tabs to an actual ground connection nearby to address possible ESD issues and added a BY198 diode (in place of the RS1M diode suggested by Floobydust) across the heater connections to ground clamp the flyback pulse produced when the power is cut off to the 4μH's worth of inductance in the 8 ohm heating element and cabling in order to protect both the switching MOSFET and thermocouple amplifier.

 Obviously, I was anxious to test out these modifications so plugged it into a repurposed block filter plug adapter which allows connection of an analogue wattmeter so I could immediately see any possible power up overloading effect I may have caused as a result of these modifications.

 The point of mentioning all of this is that I could see that the soldering station was applying bursts of power after drawing a steady 80 watts off the mains supply during the initial 4 or 5 seconds heating time to 300 deg phase at the rate of about five to six times per second.

 At this 300 deg setting, the critically damped Metrawatt meter movement integrates this pulsating power draw to a reading of 10 watts with a small +/- 2W wobble imposed by the pulsations. Meanwhile, the KSGER indicates a percentage of applied power figure of 7 or 8 percent which seems reasonable enough considering the different points of measurement involved.

 Thankfully, I had managed to avoid doing more harm than good (hopefully nothing but good) in making these modifications. It would seem that your 'guesstimate' of a "leisurely 10 reads per second" is pretty well right in the ballpark (if a little less "leisurely" than the update rate seemingly used by the KSGER STM32 control algorithm).

 In view of the 0.5μs time constant (worst case whilst the extra clamp diode I've added to complement the body diode in the switching mosfet is handling the flyback pulse current), it strikes me that a 10μs delay from heater current switch off should leave the subsequent sampling of the TC voltage completely unmolested.

 A further 31 samples at a modest 50KS/s could be collected over a total off time of just 0.64ms to feed the DSP noise filter algorithm to refine our TC voltage signal so it looks like we needn't have to shut the power off for longer than 1ms in every 100 (or 200 in the case of the KSGER) when ramping the temperature up or maintaining tip temperature with the heaviest duty tip against a heavy duty heatsink load.

 In practice, it would seem that even when soldering a 'difficult joint' with the BC3 tip (the most substantial of my bargain pack of ten clone tips) at a 350 deg set temperature, it seems unlikely that the average power percentage will need to go above the 40% mark.

 JOOI, I've actually tested that just now with a British two pence coin which I'd previously 'tinned' a few weeks back. It took several seconds to establish a good thermal contact with some fresh multicore solder before the percentage maxed out around the 40% mark.

 By blowing hard onto the penny and solder tip, I did manage to raise that to 48% briefly, noticing that the reading on my wattmeter had reached the thirty watt mark as I raised my head to look at the meter. Also noted was the modest 3 or 4 degree sag on the station's indicated tip temperature during all of my 'huffing and puffing' and the more interesting rebound (overshoot if you prefer) to 360 deg before dropping back to the set temperature upon removing the tip from contact with my "difficult test joint".

 All in all, I thought this was an excellent result despite not complicating the test with actual tip temperature readings using my FG-100 tip thermometer. However, though such testing might leave me a little less impressed, the best I could do would be to read the unloaded tip temperature. Ideally, I'd need a remote thermocouple that could be applied to the tip and my 'test joint' to get a more accurate assessment of the actual temperatures being achieved in such use.

 Since none of my existing collection of DMMs sport such a K type TC probe port, I'm considering buying a K type TC probe which I can connect to the FG-100's TC terminals to read the TC voltage and hence give me a temperature readout. As far as I'm aware, the clip in TCs used by these meters are just a K type TC in a compact form so I should be able to save the expense of buying yet another DMM just for the sake of a K type TC port. If the readings from a remote K type TC agree closely enough, it might be worth modifying the FG-100 to allow a standard K type TC plug ended temperature sensor to be be plugged into it (after removing the clip in TC, of course) for any such future tests.

 The other observation I've taken note of since doing the clamp diode modification to the heater circuit (and possibly even before) is the elimination of the "New Tip Instability" issue. It seems my sporadic use of the BC3 tip over the past week or so has successfully completed the "Burn In" process, rendering it entirely stable even right up to the unboosted 450 deg limit (in theory, this could be boosted another 100 deg but I have no desire to subject my BC3 tip to any such further abuse).

 Assuming that all such clone tips will settle down to a more civilised behaviour with this KSGER station after a few heating and cooling cycles of use, I'm tempted to put them three at a time in series with a 36v 400VA transformer to dry them out "en masse" without the possible detriment of using DC bias which could activate a (seemingly) temporary electrochemical reaction during the initial drying out phase. If my hypothesis about residual damp and electrochemical reactions is correct, I'd like to minimise any such electrolysis effects even if they do appear to be only of a transient nature.

 A basic 12v 24VA transformer based "Tip Conditioner" could become a 'must have' KSGER soldering station accessory for the more prolific user of clone T12 tips. >:D Whether such an accessory would be of any use to someone who sticks with the more pricey Hakko 'originals' remains an open question. However, in view of Hakko's use of rectified (unsmoothed) AC to power the tip heaters in the FX-951 soldering stations and the absence of any mention of a need with brand new Hakko tips to do a similar burning in exercise, I suspect not.

 In any case, the benefit of a 12v transformer based new clone T12 tip conditioning 'gadget' is an, as yet, untested idea of mine. Even if it does solve the "New Tip Syndrome", it's hardly a marketable good since anyone in the position of using a KSGER or copy T12 soldering station with clone T12 tips will be looking to minimising their spending and, worst still from a marketeer's point of view, more than capable of repurposing a suitable mains transformer from their, no doubt burgeoning pile, of "salvage' to such a basic function (assuming that such a gadget is even desired in the first place).

 If this scheme to condition new clone tips with a 12v transformer proves successful, I may well decide to "sell my soul" to Youtube to sign up as a contributor to publicise my "Wizdumb" to the greater world (small as this section of it is) at large. :)

[Notes]

[1] I've already mentioned that broken Mustool G600 LCD microscope I'd received from Banggood a couple of days ago. Well, the latest upshot to that is that it looks like they want to offer me a refund of its cost (but not the 66 pence shipping insurance) with no mention of what I'm supposed to actually do with the broken unit.

 It looks like they don't want me to return it which I suspect is just the economics of the situation (I had suggested quite strongly in my first and previous reply that I didn't want to accept their offer of a replacement if they were expecting me to pay the cost of the return shipping after advising them that a local repair would not be economically viable - their other suggestion).

 This afternoon's message from them posed the offer of the refund as a question sans question mark, so I asked for clarification about whether they wanted me to keep hold of the original for their courier to collect or whether they just wished me to dispose of it as I saw fit, also pointing out the fact that they'd left the shipping insurance cost out of their refund calculation. Just for good measure, I asked them to unambiguously state their position with regard to the return, or not, of the broken microscope and my acceptance of their refund offer.

 I'm not too bothered about the 66p shipping insurance charge since, following an Ebay breadcrumb trail search, I managed not only to track down a cheaper version with the grotty plastic suction windscreen stand from a seller shipping from within the UK, I managed to find another who was offering the later version with the sturdy aluminium adjustable base for less than a quid more, making the whole deal (the net refund plus cost of the uk sourced replacement) some 47 pence cheaper than the original Banggood price plus shipping insurance charge.

 Now, all that remains is for Banggood to confirm the exact details of their refund offer - if they want the damn thing back at their cost, they can have it back - I don't need it any more for its base as an upgrade to that first cheap Ebay find. Coincidentally, I've just this moment (22:23 BST) received a second email from the ebay seller from whom I'd purchased the best of those two Mustool G600 microscope kits earlier this afternoon to inform me that it's now being posted which bodes well for an earlier delivery than the promised Thursday the 3rd of October date.

 Past experience with ebay sellers shipping out of UK warehouses has been quite good in regard of timely deliveries. It's been rare indeed for a delivery to over run its promised date of delivery (typically a week after placement of the order) by more than a day or two with most arriving within just two to four days. This is a far cry from the Banggood experience of late (only my very first Banggood order (for that KSGER and some useful accessories btw) managed to arrive within just 8 days of being ordered).

 You might think I'd have had enough by now what with a large order that I'd placed on 11th Sep still stuck at the processing stage with no indication as to why it is now four days past its promised shipping date other than to a query I'd slipped into my first reply to their initial response to my reporting the broken microscope kit.

 It appears that the problem is "out of stock" ("What! All eight items? Are you serious?" being effectively my response to that information, along with a request for more details so I can decide how best to deal with it). TBH, I'm surprised they hadn't done what they'd done with another large order where they'd split it up, presumably to get what items were in stock shipped out to prevent the out of stock items needlessly holding up the whole order - a point I'd raised in my response to this news.

 It will be interesting to say the least as to how they'll respond to my utter disappointment in their handling of this "out of stock" issue. TBH, I can afford to wait a little longer on this order since nothing is urgently needed, not even the 30V10A 4 digit LED display bench supply headline item that I managed to snag for just £37.82 At that price, some ten quid cheaper than even the cheapest ebay/amazon seller alternatives, I can well afford to bide my time.

 As I was saying, you might think I'd have had enough of my dealings with Banggood but as it happens, I only went and placed an order for 3 metres of flexible 5 core silicone cable and a DIY kit KSGER FX9501 T12 Soldering Handle for just £6.71.

 Again this was an item I had been searching for during the past week or so on Amazon and Ebay only to discover silly prices for the ones with a 4 core cable and the stupid 8 pin din plug intended for the Hakko soldering stations, typically priced at 11 quid and up for something I'd have to spend yet more money on. Searching directly on Banggood's web site had failed to unearth where this little gem had been hidden (it even includes the GX12-5 connectors (both the panel and the handle connectors - Yay!) and it was not until I tried a duckduckgo search with the inclusion of they key word "DIY" that I finally discovered where BG had hidden it.

 No cable supplied though, hence the purchase of 3 metres for just £4.14 for me to split into 1.5 metre lengths for the spare and to upgrade the 1 metre cable currently attached to my existing iron handle. I much prefer a DIY assemble it yourself kit over the ready assembled units simply because it saves the time you'd spend taking such ready made handles apart in order to fettle the typically piss poor quality of assembly seen in these items of 'best Chinese manufacture'. This way, you'll know exactly how good the quality of assembly will be before using it in anger. :)

 In spite of several reviewers' prejudices against its cheap "plasticy" construction, I was surprised at how difficult it had proved to be to locate one at the hoped for 'cheap' price point. I had deliberately chosen this particular KSGER T12 soldering station package for this soldering handle, seeing through the reviewers' prejudices to recognise the charms of its quick tip change, light weight and short tip to grip distance with the latter being the overriding charm of its construction in view of its intended purpose of soldering smd components onto cramped circuit boards where the last thing you need is a hulking great tip retention collect to get in the way of a long distance tip. Quite frankly, I'm rather relieved that I was finally able to track down and order another one so cheaply as a spare. :)

JBG
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on September 30, 2019, 10:13:29 pm
Quote
In practice, it would seem that even when soldering a 'difficult joint' with the BC3 tip (the most substantial of my bargain pack of ten clone tips) at a 350 deg set temperature, it seems unlikely that the average power percentage will need to go above the 40% mark.

 JOOI, I've actually tested that just now with a British two pence coin which I'd previously 'tinned' a few weeks back. It took several seconds to establish a good thermal contact with some fresh multicore solder before the percentage maxed out around the 40% mark.

 By blowing hard onto the penny and solder tip, I did manage to raise that to 48% briefly, noticing that the reading on my wattmeter had reached the thirty watt mark as I raised my head to look at the meter. Also noted was the modest 3 or 4 degree sag on the station's indicated tip temperature during all of my 'huffing and puffing' and the more interesting rebound (overshoot if you prefer) to 360 deg before dropping back to the set temperature upon removing the tip from contact with my "difficult test joint".

All this stuff is fine and all, but you can't rely on the temperature readout of the station. W/e you measured is meaningless, because we already know 350C >> 200C, and 200C is enough to melt solder. The point of everything I mentioned about sensor/heater coupling means that the station does not necessarily know the correct temp of the tip. You have to measure the temp of the joint while you're doing it, using an accurate temp probe. By putting a temp testing thermocouple, for instance, between the tip and the 2 pence coin.

When the station display reads 3-4 degrees low, the joint might really be 40-50C low (Maybe 25C lower than a "good iron" under this same test, because both will sag between base of tip and the point of the tip that 25C. But the T12 clone WILL have additional sag from the sensor coupling, unless it is able to correct for this). These numbers are just thrown out and will vary by size of heatsink. Greater the heatsink, greater the sag. When it "overshoots up to 360" it is likely still lower than 350, and it might still be 30-40C low. This is my experience/finding with cheap T12 clones, and I suspect there are more than just the two varieties of clones I have experience with which don't bother to try to correct for this sag/error.

So just because the iron doesn't need to go above 40% duty cycle to melt solder on to the coin doesn't mean the temp isn't sagging. (If you use a firestick that is controlled by a dimmer, it can also melt solder onto stuff at a reduced duty cycle that hits 350C at no load). IOW, just cuz it's only at 40% doesn't mean that you can solder to a larger heatsink without bumping up the set temp. It's not like the iron will necessarily bump up duty cycle to 80% in order to maintain the same temperature at the base of the tip on this larger coin. It could bump up duty cycle to 70% and allow the base of the tip to sag even lower from the set point under no load. If the error is not corrected, the temp will sag in relation to size of the heatsink; that's how the coupling error is expected to behave. The display will show artificially high numbers and obviously cut power because it assumes it is at set point. And the iron that corrects for this sag would go to a higher duty cycle and keep the joint closer to the no-load set temp. IOW, if you turn down the set temp on both irons (and actually measure set temp not trust the display, of course), the one with worse or nonexistent temperature correction is going to stop being able to solder to that 2 pence coin, first, despite set temp (under no load) still being significantly higher than 200C and identical to the better iron which is still able to solder to that coin.

Because all irons sag between the base of the tip (where the sensor is) and the point of the tip under load, this can't easily be removed from the reading. You have to compare two irons and they both have this sag. This is why you must use similar size and shape tip, to that effect, so that the temp sag between base of the tip and the point is consistent. And of course you have to choose test joint/sink which is not so big that the iron cannot reach its (good or flawed) set point under even max duty cycle. (Fact that the iron does not go above 40% duty cycle is the proof that this sag is due to control circuit not maxed out on power; the station COULD do better if it had better sensor data/handling). Just purely a guess, cuz I don't know what a 2 pence coin looks like, but I would guess with the BC3 tip, my own clones might start to fail at around a true set temp of 300-320ish whereas the 888 would keep trucking no problem.

The T12 BC3 tip has every advantage over the T18 C3 tip regarding sag between the base of the tip and the point. It is shorter and the tip tapers down to 3mm bevel. The T18 is about twice as long and is closer to 3mm cylinder the entire length between base and tip; it doesn't have the fat taper to the thicker base. (This is what the "B" in "BC" means; it means that it's a hybrid bevel/conical... a conical base that ends in a bevel at the tip.) And Hakko 888 C3 tip significantly beats clones using BC3 in this test. So it is easy to see that there is additional sag due to heater/sensor coupling in some T12 clones.

Ideally, the test joint will be purely a heatsink and it should not require necessarily a heavy thermal mass/inertia of its own. A blank piece of copper clad is more ideal than a 2 pence coin. To get a meaningful result, you should wait, in either case, until the heatsink has attained a stable temperature and no longer changes. The sheet of copper clad will be a bit more stable. The pence coin will be more sensitive to ambient air and convention currents and w/e heatsink you're setting it on and pressure between the two.

I suspect many clones fail to correct for the coupling error. But because you describe behavior that hints at only a super slow 5 reads per second, I am hoping that this KSGER version actually attempts to do this. I might have to buy one to test just for the hell of it.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: KL27x on October 01, 2019, 08:41:54 pm
You mentioned earlier about moving the tip of the thermocouple heater/sensor away from the rest of the main coil, in order to reduce this coupling effect. I wonder what happens when you put an intermediary conductor between the two halves of the thermocouple. This should stop the effect, maybe?

So you have your heater coil, and the two metals don't connect, directly. There is an intermediary material that electrically connects them. Then there's just two tiny gauge wires of the thermistor metals that connect to the heater wires, directly, bypassing the intermediary conductor. The ends of these two tiny sensor wires are directly connected and placed a tad away from the heater proper, perhaps a bit closer to the tip.

I still think error correction will improve even this setup, though. So I doubt it would be worth the cost IF error correction can be done well.

Hum, naw, that doesn't work. The intermediary conductor will short the voltage produced at the tip.
Title: Re: Hakko still the best option for a good quality hobbyist soldering station?
Post by: Johnny B Good on October 03, 2019, 03:08:28 am
 Just keep in mind that the thermocouple effect arises out of the temperature gradient between the hot and the cold junctions (Seebeck effect). No voltage is actually produced at the junctions themselves.

 I must admit that until I read that wikipedia article on thermocouples, I had assumed the voltage was produced at the junctions. It turns out that you can even connect the thermocouple alloy wires via a third metallic alloy, say a crimp, and not have it effect the voltage generated by the Seebeck effect provided there is no temperature difference between the thermal wire junction connections to the bridging crimp.

 Ignoring the ageing effect for the moment, it doesn't matter that one or both thermocouple wires run at an elevated temperature along their length compared to the hot end junction. The voltage produced is purely defined by the difference in temperature between the hot (measuring) and the cold (reference) junctions.

 Unfortunately, most base metal alloys used for the cheaper, less exotic TCs suffer an ageing effect which typically results in a reduction of sensitivity and is aggravated by running the wires through an elevated temperature region such as the heater portion of such a combined heater and TC direct drive cartridge. Hakko have obviously chosen the most economically priced alloys used to achieve virtually no such ageing effect, accepting the halving of sensitivity as the price for such stability.

 One might assume that the clone tips use the same combination of alloys to maintain compatibility in regard of the TC sensitivity but there may be other cheaper alternatives that could match the ~20 microvolts per K sensitivity of the Hakko tips so only time would tell whether they've used the same alloys and hence have the same agelessness of the Hakko originals.

 If it turns out that Hakko had chosen the cheapest possible solution, this is unlikely to be a factor in the quality of the clone/fake tips (but that still leaves many more ways for these cheap clones to fall far short of the quality of an original Hakko tip).

 Regardless of the exact mechanism involved in the NTS effect with these clone tips (galvanic or possibly a pre-compensation effect for a thermocouple ageing process), there still remains the option to use Hakko original tips making these cheap STM32 based soldering stations worth taking a punt on for hobbyist level use if you're prepared to remedy their blatant safety issues and the poor quality of assembly of the supplied soldering handles.

JBG