EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: timg11 on June 19, 2021, 04:06:11 pm
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I have a number of almost 40 year old double-sided boards with unsocketed DIP ICs I'm working on restoring and repairing.
(https://www.rhodeschroma.com/content/voiceboards/rhodestracecut/1front.jpg)
I'm looking for a good quality desoldering station that will allow the DIP ICs to be removed without damaging the board or traces.
I've looked at the Chinese "Proskit" type, but they seem to be too low of quality, and are not available from reputable sources.
I was able to borrow a Hakko FR-301 for a day, and it kind of worked, but didn't seem to extract enough solder to allow the DIP removal, and left so much residue in the hole that a socket could not be inserted.
Can anyone recommend other options for desoldering stations? There don't seem to be that many around these days....
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it helps often to extract, then put fresh soldier on the pins, and extract again.
the fresh flux inside the soldier makes the removing easier.
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It can be tricky, especially if the boards are dirty. I'd start by cleaning the area with IPA. PDIP removal can be tricky, here's what works for me.
First, the FR-301 is excellent. I haven't used the Pro'skit one, but Pro'skit stuff is generally of acceptable quality. The key points with desoldering are making sure the equipment is working perfectly and having the right nozzle. I use an extended snout 1.0mm with the FR-301, I'm not sure what is available with the Pro'skit model.
Some items you need or may want, depending on what procedure you want to use and whether you want to save the chips themselves:
PDIP puller: https://www.ebay.com/itm/124627920061?hash=item1d046724bd:g:PhcAAOSwjGVgSrnb (https://www.ebay.com/itm/124627920061?hash=item1d046724bd:g:PhcAAOSwjGVgSrnb)
1.0mm extended nozzle: https://gokimco.com/collections/hakko/products/hakko-n61-12-high-power-desoldering-nozzle (https://gokimco.com/collections/hakko/products/hakko-n61-12-high-power-desoldering-nozzle)
Low-temp solder and flux: https://www.amazon.com/ChipQuik-SMD1-Leaded-Temperature-Removal/dp/B0019UZP7I (https://www.amazon.com/ChipQuik-SMD1-Leaded-Temperature-Removal/dp/B0019UZP7I)
Hot air station with small nozzle: https://www.amazon.com/Rework-Solder-Station-Soldering-Welding/dp/B07Y7ZCVT2 (https://www.amazon.com/Rework-Solder-Station-Soldering-Welding/dp/B07Y7ZCVT2)
or, possibly, a PDIP soldering iron tip (not the way I do it) : https://www.digikey.com/en/products/detail/stan-rubinstein-assoc.,-inc-dba-sra-soldering-products/AOLF-1403/10709949 (https://www.digikey.com/en/products/detail/stan-rubinstein-assoc.,-inc-dba-sra-soldering-products/AOLF-1403/10709949)
So there are two ways I might remove the PDIP. If the board is very high value and the chip is toast, I may nip all of the leads off the body of the IC, then grab each one with a locking hemostat and put some tension on it while I desolder it with the desoldering gun. The other way is to remove as much of the solder as I can with the gun, then put some tension on the whole IC with the PDIP puller while I heat the area with the hot air gun, carefully working it out. This is usually successful, but if I'm very concerned about damage or if I want to save the chips, after the initial desoldering I will add flux then then resolder with the ChipQuik solder. Then desolder again, and carefully work the chip out with the PDIP puller while heating with the gun--the advantage is that you can use a lower temperature during this last part which will reduce damage to the chip, board and surrounding solder joints.
After you are done, clean up the pads carefully with the desoldering gun. You want to clear the holes with vacuum if you possibly can, because poking or drilling can damage the traces or through-hole plating.
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@bdunham7 thanks for the helpful post.
Good to know the FR-301 is a good choice and thanks for the tip on the extended 1mm nozzle.
Some of the PDIPs are rare and I try to preserve them. Others are still available, so I've used the "cut off the leads and remove one by one" process. Sometimes depending on clearances, I've tried cutting the DIP down the middle so the package can be split into two SIPs, which can be gripped with hemostats and sometimes are faster to remove that way.
The low-temp solder is an intriguing idea - I have some 63/37 eutectic solder, but this stuff must be an alloy that contains lots of silver and platinum, given the price.
I've got the DIP puller and hot air station. I even have a solder pot for the situation where the component is wanted but the board is expendable.
That DIP-shaped soldering tip is an interesting idea - I remember seeing those years ago. I searched recently, but but didn't find it anywhere, let alone Digikey. I can't tell what type of soldering iron it goes into - probably not my Weller WES51 or my Metcal.
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You don't really need a desoldering station, just to use proper technique and tools!
Before I'd get to the technique part, I'll point out what you need to have:
1. A proper PCB holder, so you could work more easily on circuit boards:
https://www.aliexpress.com/item/4000083032653.html (https://www.aliexpress.com/item/4000083032653.html)
2. A set of solder assist tools:
https://www.aliexpress.com/item/32824103889.html (https://www.aliexpress.com/item/32824103889.html)
3. A set of tweezers:
https://www.aliexpress.com/item/32945877194.html (https://www.aliexpress.com/item/32945877194.html)
4. A set of chip removal tools:
https://www.aliexpress.com/item/1005002612794435.html (https://www.aliexpress.com/item/1005002612794435.html)
Of course you could also get these locally from places like Amazon (but they'd prob cost you double!)
Now, to the technique part, bridging is your friend! Use leaded 63/37 solder, bridge all pins of each chip (from the rear end of course), do it one set of pins at a time, then heat up the pins, while pulling the chip from the other end at the same time (with one of the above tools), get one half ot it out, then repeat with the other til it's all out. When done, use solder wick (or a combination of solder pump+wick) to clean up the solder. Bridging is an excellent technique for removing multi-pin components and connectors, and I've used it dozens of times myself. Good luck!
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Some of the PDIPs are rare and I try to preserve them.
Then the ChipQuik + double desoldering is the way to go. I recently removed some 20-pin PDIPs that I wanted intact and they had been originally installed by bending all the pins over before soldering. I was able to mostly straighten them on the first desolder fairly quickly, and then a bit more on the second round, then pulling them through the holes straightened them out the rest of the way. Board and IC survived. You definitely don't want to linger with the heat and you should allow cooling between rounds.
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pace works fine for this, get the tip that is a good size for the hole, the problem you have sounds like wrong tip size more then anything else, it has to make good thermal contact but also have the correct suction clearance, and if you are using a use tool the tip might be worn (the bore size increases as its used more, eventually leaving to bad thermal contact and too large suction area (the pump has optimal channel dimensions for removal)
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I do have a vacc de-solder station.....mostly I wouldn't bother using it to remove thru hole I'd cut the legs de-solder the pin with an iron and tweezers as suggested.
But if the ICs are valuable and unknown if faulty.......yes a de-solder iron is very helpful. You can save ICs (I prefer not to). Hold the PCB vertically...put on flux (both side), reflow the pin with a touch new solder. Let it cool, now hit the desired pin from top side with std iron and base side (same pin) with de-solder tool. This ensures all the solder is at melt point.
Ensure at melt point....Vacc it out. Let it all cool, repeat for all pins. This is the best way to removal "all" solder. Or you can use the vacc tool in circular motions on the pin....which helps but tends to tear at pads. I ensure I only have the irons on for seconds as rework like this easily kills pads.
Which brings us back to "cut the leg" method......its quick saves pads.
FWIW
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I have a number of almost 40 year old double-sided boards with unsocketed DIP ICs I'm working on restoring and repairing.
(https://www.rhodeschroma.com/content/voiceboards/rhodestracecut/1front.jpg)
I'm looking for a good quality desoldering station that will allow the DIP ICs to be removed without damaging the board or traces.
I've looked at the Chinese "Proskit" type, but they seem to be too low of quality, and are not available from reputable sources.
I was able to borrow a Hakko FR-301 for a day, and it kind of worked, but didn't seem to extract enough solder to allow the DIP removal, and left so much residue in the hole that a socket could not be inserted.
Can anyone recommend other options for desoldering stations? There don't seem to be that many around these days....
That is almost 100% certainly due to improper technique. I work with apprentices all day long, and desoldering is a constant problem, as most have never been trained in proper desoldering technique. The biggest mistakes they make are not properly tinning the desoldering tip, not waiting for full solder melt, not moving the pin during suction, and not applying suction long enough (resulting in clogging).
Watch this video from PACE. It’s part of a video manual for an old model of theirs, so you can ignore the product-specific bits, but the technique shown is applicable to any continuous-vacuum desoldering device. The actual THT desoldering process is at 17:55–22:25, but I recommend at least skimming through the whole video.
https://youtu.be/IqE1KA0OAnM (https://youtu.be/IqE1KA0OAnM)
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Ensure at melt point....Vacc it out. Let it all cool, repeat for all pins. This is the best way to removal "all" solder. Or you can use the vacc tool in circular motions on the pin....which helps but tends to tear at pads. I ensure I only have the irons on for seconds as rework like this easily kills pads.
If you’re damaging pads, then you’re doing it wrong. Watch the same segment of video I recommend in my previous reply, as it specifically addresses this problem.
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I can guarantee you "circling the vac tip" can put enough pressure on a pad to do this. Depends upon how well the PCB was made. Also not all Pads/drill holes/pins are the same. So use tight drill tolerance some not.
The Video is simplistic stating the tip never touches the pad.....errr Yes it does in practice. I understand what they are saying but in practice is a lot different. They stated you should have a complete vacc clean in 2-5 seconds...I kinda agree...but like to be a bit quicker than 5 seconds. They also went from pin to pin too fast not allowing cooling.
Military multilayer PCB quality is a better standard than most. But we found its better to use 2 irons, one top of leg, vac on base. F18 micromin PCB repair. Quicker easier, less heat as twin irons makes it quick. That said sometimes we use 2 persons to do this.
Indeed they do this is the Pace video...this is my (and was for micromin....but may have changed) preferred method.
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Pace SX-100. I repair too (as a business) and often a repair of an industrial or maritime board is desoldering all ICs and semiconductors and then test them with my big collection of component testers. The SX-100 is the best I have tried. It gets everything loose, from heatsinks to tiny zeners. I seldom damage a pad. Tips are cheap. I use 8 different sizes and the right size is the key to successful desoldering. My pump/psu unit is over 25 years old and the pump is still like new.
Pace has some videos about how to desolder. I learned a lot from them.
- the right size tip, as stated this is the most important key to succes.
- first "resolder" old "dried/oxidised" solderjoints that will not melt all the way through.
- circle the desoldered pin to prevent rewetting
- if holes are small compared to the pin you always get some rewetting. You can sometimes "break" the rewetted joints with a tweezer. But for severe cases I remover all solder and then use my hot air station. It takes about 10 to 20 seconds to then come loose.
- There are boards with very thin pads. The tip must be as big as the pad. If the nozzle is to big you go not heat the pad and hence, do not touch the solder
- The hardest are double sided boards without vias. They are rare in my type of work but I have seen them in very old (tube area) stuff. Remove the bottom tin. Then melt the top and pull the pin.
- single layer pads without vias like in cheap consumer stuff is hard to desolder. Not to melt the solder but the pads are glued to the board and come loose just by looking angry at them.
- do not use tips as a crowbar to straighten bend pins if you want them to last long.
- Never press the tip on a pad. The weight of the handpiece must be enough. Pressing harder is the way to remove or damage pads.
- use your ears. You can hear the air sucking through the hole and if you desolder 8 pins they need to sound alike. I one sounds different most times it not desoldered enough
- If the tin on the topside does not melt it is often better to resolder the part before sucking again
- If the first suck is not enough to complete remove the solder then first resolder the pin and try again. You need enough solder to transport the heat effective from tip to solder/pin/pad/via
- conformal coating makesthings a lot harder
My personal experience, I prefer a higher temperature (350-375 degrees C) and for many-multi-layer boards with huge heat absorbing planes I sometimes go up to 425. But keep in mind: high heat AND a shorter time. More heat, to much pressure and a longer time is the receipt of killing a lot of pads.
But I desoldered a lot components over the years and like soldering, desoldering is an art on its own you need to learn by theory and then a lot of practice. So practice on old boards.
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I also own a Pace SX100. It's more expensive than the Hakko but it's a station based handpiece rather than a gun so lighter and easier to use both horizontally and vertically. Has a larger range of tips and overall cheaper to run.
One of the problems of vacuum desoldering pumps is clogging, so frequent (and cost effective) filter changes are import. If wear occurs in an integrated part or tip some models get crazy expensive to run. The Pace SX100 negates a lot of this as the breakdown of the entire vacuum path and tips are low cost consumables, I'm not exaggerating this.
When soldering/desoldering apply as little pressure to the pad as possible. Often a reason people put pressure on a joint is they were originally wave or lead free soldered. So there is next to no solder on the joint or a oxidized layer acting as a thermal barrier. To solve this add a little solder with your iron beforehand that way it breaks up oxidization and flows the joint and can make desoldering easier. Same goes for a hand vacuum pump.
Don't be concerned about time so much, 5 seconds is quite reasonable to ensure a proper desolder. It's far better to have a success at a conservative temp than several goes at a high temp due to rushing. Like with soldering you alternate pins to ensure your aren't baking the component in the process.
https://www.youtube.com/watch?v=K2UWxi9V00o (https://www.youtube.com/watch?v=K2UWxi9V00o)
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Look I agree with the principles involved in thru hole de-soldering by the users above ...but it never works in practice as perfect as that. I do follow, in general, the above practices but my station tip replacement (old royel ex military de-solder handset and controller) ..ex military micromin PCB repair for fighter acft...it's a bit more difficult to replace tips than the Pace.....yet I have plenty of tips and hand-sets.
The Vac pump capacity is more than enough (I have 2 main de-solder main units) .. Funny enough it crapped out the other day (it produces Vacc and +ve pressure) ...the vacc pressure was low...I fed thru cleaning solution (as advised by other EEVblog users)...fixed it.....these are 3 A Gast pumps...way over specc'd
cheers
Bren
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compared to the hand held desoldering tool its amazing, I used it for years and this is basically perfection in comparison.
The other good tool is to get the needle hot air blower, which I bought by accident, because you can blow out holes that for whatever reason have non removable solder in them.. I notice this on old PCB sometimes. I tried to refill and suck with pace and blah blah you can try to put wires in there and then suck around them and fool around or blow it out like a pro, the anteater stuff gets frustrating
I have not had to go into one but a high end high thermal mass switching mode power supply board or high end power RF section is the perfect candidate for the blower tool because i find they have the most difficult extraction jobs in them. Its still a hassle to clean off the solder afterwards but at least its a real solution without fooling around (needs a very professional inspection afterwards to look for errant solder bits).. multilayer high power sections have stuff that just goes wrong with the extraction sometimes
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What is a needle hot air blower ? I have a normal hot air station but I do not think it has enough power to blow out the solder from a hole that even my SX100 can not get out (What never happend, but who knows, up to now the heaviest switching PSU I had on the bench was only 6kW 8) )
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their irons that plug into the old pace pump stations that have a soldering iron that passes air through the tip the size of a sports ball inflation nozzle
https://www.edsyn.com/product/1036.html (https://www.edsyn.com/product/1036.html)
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OK, I know them from pictures but I wonder what they are made for. They are still for sale and I wanted to buy one because I often have to fire up my hot air station just to remove one resistor or shrink some tube but it needs time to warm up and only shuts down if it is cooled (all the time making noise)
I have not yet bought one because I think it is not able to (de)solder due to the size and the pump has not a huge amount off air capacity.
But if yours can blow the solder out of a hole I could be wrong and it could be useable. I use it for my work every day.
I have the tweezers but I almost never use them for SMD because it is rather big (I do not have the special pretty expensive IC tips because hot-air works well enough)
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I only used it to blow out holes that have light coming through them but have dimensional issues where a part lead wont fit because of some amount of solder
and sometimes it wont blow it clean, but instead blow the solder out and have it get stuck on the outside of the PCB like a mound, but then you can use solder wick to get it out since its clear of the plated hole
trying to wick it out on a bus wire is sometimes better though, because this method is pretty messy, it leaves solder splatter. careful around high pin density, maybe its a sign i use too high air pressure. i use the old pace graphite pump boxes that accept 3 prong soldering irons and raise the heat fairly high. careful not to get solder in the heated part because its possible to get it glowing red hot and spit out fireballs (always when you heat it up aim it into a safe area first to make sure nothing got into the tip)
did not use it too much but when I have a job where I know I need to desolder alot of different crap (dip + transistor + capacitor) I turn it on because its highly likely I will be left with some difficulty somewhere
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also for SMD did you consider pulse heat from pace? I got the resisttweeze (dual resistance heating elements in tweezer configuration) and they are pretty good for taking off 2 component SMD. The big soldering iron chop sticks are no doubt more precise but I think its a good tool even if the thermal control is a little simple in comparison. Looking to try the conductweeze (the direct resistance soldering) on some 4 pin solder cup power connectors for my nanovoltmeter soon... nice benefit for that tool if you also use the thermal wire stripper, its fast to heat up with the foot pedal.
But what I did is I setup a special repair bench with the pace extractor, pace pulse heat, a hakko fx888 and a old weller station + fluxes, solvents, deoxits, solders, etc.. I work down there now on any repair or assembly job, and its next to my tool boxes which have all the stuff for doing cables, glue, etc. and all the dust cleaning stuff (3 different kind of wipes, etc), and trays for screws..
I find it nice not to have the equipment or assembly jobs on my test bench anymore. I found that combining the two had little practical benefit for me. Since I setup the technician area I was able to service a ridiculous amount of equipment in the last season. I also did a generally better job like cleaner PCBs, nicer fixes, etc since the split. At least for simple devices that generally you know need alot of work, if its repairing intermittent issues in an oscilloscope you have something else completely.. the bench I have in mind is a little 'dull' intellectually but you get everything polished tightened cleaned reliable and so forth, even if the most complex problems are not solved, but that still gets you somewhere. Only things that missing is a sink with ultrasonic nearby (i still do this in the kitchen).. but once its setup well I can take panels out and take em to the garage for buffing or whatever I feel like doing to make it look great, without feeling too overwhelmed.. maybe you can call it a commercial restoration setup or something
but things like taking apart ganged switches on your main work bench? screw that!
Maybe call it a precision small scale electromechanical work area
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Desoldering hollow needles are your friend, since you can heat the pin long enough to ensure both layers are fully molten and then push it in.
This is especially useful if you don’t have through hole plated holes.
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I have seen those in a video, I would like to have a set for repairs that have damaged vias because the owner first tried it himself.
I am now looking for a second reworkstation but that became more difficult as I thought. The only Pace dealer over here seems to be Farnell but they almost have no stock. There was a Pace department in England and at that time Farnell had a good stock. But the same goes for JBC, there is one Dutch dealer (but it is a very good one) The only brand that seem to have a solid dealerbase is Weller but I have no confidence in the weird looking desolder piece Weller makes. My number one still is Pace (MBT350, SX-100, PS-90 and a thermojet TJ70 or 85) But that is intellyheat and I do not know yet if the tips are interchangable with my sensatemp MBT250.
If not, I think I will also look at JBC (Although I do not like cartridge systems, but on the other hand, I just repaired an industral PCB that costed me 2 desolder tips thanks to the insane hard conformal coating, I can add those to the bill and then 20 euro for a JBC tip is reasonable. (pace tips cost half of that but only sell per 5 and that sucks because there are special sizes I want but almost never need so five is a bit overkill, they last forever) For 200 euros I have the 8 different size JBC tips i want, for Pace that would be almost twice or triple the price (But gives me 40 tips, nice but most of them I would probably never use. There are 2 sizes I use 90% of the time, I need the other sizes but they last for ever) ). I know some people who have very good experience with the JBC solderstations and they have almost everything I like/want.
But for me the performance of desolder handpiece and availability of tips is the most important. For incidental use even crappy Chinese are usable. But for my kind of work I need the best, and upto now, for me that is the SX100, it does everything I want. But if I have to wait for weeks in the future everytime I need a sparepart or tip, that becomes frustrating (if you are going to spend over 3000 euros for soldering stuff you do not want that) But this is not my topic so I will start a new one if needed.
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I’ve used many Metcal desoldeing stations and have had excellent experience with them.
They may be old but work great, many were running almost 2-3 hours a day 5 days a week.
However even after using these so frequently I still opt for my desoldering needles with some leaded solder and high wattage soldering iron
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i do not like those needles from the videos
https://www.youtube.com/watch?v=2wcFr-lO9Eo (https://www.youtube.com/watch?v=2wcFr-lO9Eo)
looks kinda janky
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I have a PACE MBT250 at work and a Proskit SS-331H at home. They both work pretty nuch the same. Yeah you should probably clean them every time you use them. I do every other time, but if I was working on larger projects I would do it every use.
The Proskit seems to have pretty good availability of spare parts on eBay, AliExpress, and Amazon. The PACE I think I needed to order from Farnell.
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I have the MBT250 with TT65, PS90 and SX100. I also have an old SX70 from when I bought the station but the SX100 is no compare, it works so much better. I dived into it this weekend and the Pace MBT350 including everything I need (including a ton of tips (5 for each size except for the micro tweezers and TM100) sits just under 3000 euros while the same setup for JBC goes way over that. But I do not need a microsolder iron and tweezers and then there is a JBC with hotair, desolder and solder handpiece. But if I stay with Pace I can use the thermojet, SX100 and all tips on both stations (in theory, I have not yet sort out the connector difference) and in case I have one that fails, just when I have a pile of work, I can use the one from the other station. I can buy the MBT250 but that costs more with 3 handpieces as the MBT350 with 5 handpieces
For others thinking about rework tools some thoughts about Pace but also in general:
The Pace MBT250 is sensatemp, a pretty good way to keep a very accurate tip temp. No cartridges but my PS90 outperforms my Metcal (that was a waist of cash) and I do not need the fast auto on/off. The handpieces have a black connector, tips are cheap and very long lasting.
The MBT350 is intellitemp, the connectors are blue and the station can use both modern cartridge and sensatemp handpieces. I do not know if the pinout is the same, if so there was no reason to use an other color. (i will ask Pace for advise, they always advised me great in the past)
They still produce both units but if you want price advantage you buy a base-kit and then add the rest. The same for handpieces, a spare handpiece cost almost the same as one complete with toolholder but if you buy both separate the toolholder alone is around 85 euro.
The SX90 and SX100 use different tips. The 100 tips make contact with the heater over a much longer distance. I think 90 tips will fit the 100 but I do not think the 100 tips fit in the 90. The 100 tips have a trumpet shaped end. For me the only downside. As a test I removed the trumpet from my most used tips and used both versions for several months next to each other. I did not notice difference in performance but without the trumpet you never have to remove a huge ball of solder tacked to the trumpet. I now have removed all trumpets with a file.
Things to look for when you want a desolder gun is the amount of suction and the amount of air but even more important is the start when you press the switch. Pace calls that snap-vac, it takes 150ms to get max suction. This "shockwave" start is important to get the initial moving of the solderblob. Hakko uses some sort of valve technique to get this effect. I could not find that for JBC but I found a video where they compared both (and some better Chinese stations) and the Hakko was just a bit better as the JBC but both where much better as the Chinese ones.
An other thing is durability, tips suffer a lot from things like the moving in circles, bending pins up if they are bent against the board and then soldered, from conformal coating etc. So take the price of tips into your budget for operation-costs. But that is not all. The fliters clog up reducing the airflow. I like pace for this because they are easy to clean (I wash the filters in IPA and now they last over a year instead of weeks. I just switch them but if I have time I wash the dirty ones. I use a little dot of steelwool in the traptube (I use the glass one but have a few disposable carton ones as backup)
In the year I had the Metcal I needed to clean and replace the worn pump membrane a few times (I had two pump units) My MBT250 pump is very old (several decenia) and has a very hard life. I opened it a few times but it looked inside like new and even the membrane was like new. So the filters do a pretty good job and my filter washing does not seem to have a negative effect) I heard from someone Pace used to advise to clean the pump so every now and then by pumping IPA through it (the guy who told me that he connected a piece of tubing instead of the handpiece and then used that to suck in IPA instead of air. It then returned through the hose h connected to the output nozzle and this way pumped it around. I have done this once about 10-15 years ago but the IPA came out as clean as it went in, so I never bothered to do that because opening them also always showed a clean pump.
And for last, desoldering is a technique, it is more difficult as soldering because you have to deal with old solder, coatings, dirt, corrosion, pads that can come lose, vias that can damage etc. Pace has some excellent videos made in the 80's but still very usable. Add solder if the solder will not melt within 2 seconds or so due to corrosion of the outer layer. Conformal coating on top of the PCB is something that can bite you in the b%lls. If the solder melts but the coating not, there can not be an airflow through the hole. The solder melts but does not come out 100% or even none at all. Jus use a needle or scraper or whatever, to remove the coating enough for air to pass through. If a via is torn in 2 the solder will only melt on the side you apply the heat, but resoldering a new part can prevent the solder to flow also to the top part of the via and this way you can get a very bad connection between top and bottom trace.
Never apply pressure, this is the 100% sure way to kill a pad. If it does not melt add some fresh solder
Use the right size tip. Not to small (or solder can not pass) the tip must more or less mach the inner and outer diameter of the pad , it must not wider as the pad because in that case you will not melt anything but the epoxy :-)
Be extreme caution with single layer consumer grade pcbs with no vias. Those pad come loose even if you think about desoldering them. The right size tip and temperature is very important in those cases.
The solder gets sucked straight up against gravity, I often shake the handpiece a bit while I let the pump running. The metal Z strip in the reservoir then moves and prevents a ball of cold solder just above the tip-tube. But if possible I mount the PCB in a 90 degree angle, seems to work just a bit better.
Clean the tips bores. The get clogged with burned flux, coatings, oxides, dirt etc. Do this careful, you must not damage the coating (inside and outside) tip reactivators do a great job to keep your tipsa in shap. I use the stuff from Weller. It coats the tip. I also usd it on my DIY tips (I sometimes make for special situations)
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I have the MBT250 with TT65, PS90 and SX100. I also have an old SX70 from when I bought the station but the SX100 is no compare, it works so much better. I dived into it this weekend and the Pace MBT350 including everything I need (including a ton of tips (5 for each size except for the micro tweezers and TM100) sits just under 3000 euros while the same setup for JBC goes way over that. But I do not need a microsolder iron and tweezers and then there is a JBC with hotair, desolder and solder handpiece. But if I stay with Pace I can use the thermojet, SX100 and all tips on both stations (in theory, I have not yet sort out the connector difference) and in case I have one that fails, just when I have a pile of work, I can use the one from the other station. I can buy the MBT250 but that costs more with 3 handpieces as the MBT350 with 5 handpieces
For others thinking about rework tools some thoughts about Pace but also in general:
The Pace MBT250 is sensatemp, a pretty good way to keep a very accurate tip temp. No cartridges but my PS90 outperforms my Metcal (that was a waist of cash) and I do not need the fast auto on/off. The handpieces have a black connector, tips are cheap and very long lasting.
The MBT350 is intellitemp, the connectors are blue and the station can use both modern cartridge and sensatemp handpieces. I do not know if the pinout is the same, if so there was no reason to use an other color. (i will ask Pace for advise, they always advised me great in the past)
They still produce both units but if you want price advantage you buy a base-kit and then add the rest. The same for handpieces, a spare handpiece cost almost the same as one complete with toolholder but if you buy both separate the toolholder alone is around 85 euro.
They are not the same pinout.
To date, Pace has really only had 4 different control systems:
-"dimmed" mains AC
-SensaTemp
-IntelliHeat/HeatWise (cartridge heater)
-AccuDrive (cartridge heater)
All of the low-voltage systems use Amphenol C091 B series DIN connectors:
6-pin black is the SensaTemp connector, containing only the SensaTemp signals.
8-pin blue is the "IntelliHeat" connector, containing both IntelliHeat and SensaTemp signals.
4-pin red is the "HeatWise" connector, containing only the IntelliHeat signals.
4-pin black is the AccuDrive connector, containing only the AccuDrive signals.
SensaTemp handpieces can be adapted to work on stations with IntelliHeat sockets using this adapter: https://paceworldwide.com/6-8-pin-gender-bender-adapter
The SX90 and SX100 use different tips. The 100 tips make contact with the heater over a much longer distance. I think 90 tips will fit the 100 but I do not think the 100 tips fit in the 90. The 100 tips have a trumpet shaped end. For me the only downside. As a test I removed the trumpet from my most used tips and used both versions for several months next to each other. I did not notice difference in performance but without the trumpet you never have to remove a huge ball of solder tacked to the trumpet. I now have removed all trumpets with a file.
The SX-100 and SX-90 handpieces are practically identical. They use all the same spare parts, and other than the change in the color of the printing, I am unaware of any actual difference. (I spoke with Pace on the phone and asked, and the guy said there are only tiny differences.) For all intents and purposes, they're just different revisions of the same model, and indeed, the SX-100 uses the same SKUs as the SX-90.
It's the SX-80 (which is almost identical to the SX-90 and SX-100) that cannot accept the flared-tube tips. An SX-80 can be upgraded to an SX-90 by replacing its heater assembly with an SX-90 heater. (Note that SX-90 heaters come in two types, with different headers, black or blue, connecting the handle to heater.) SX-80 tips are similar to SX-90/SX-100 tips, but less heater contact and without the flare. The SX-70 (still available!) uses tips that have no tube and are not compatible with any later model. See the attached image from the SX-100 manual (which, other than its title, is identical to the SX-90 manual.)
Anyhow, according to Pace, the idea behind the flare is for the airflow to cause the solder to spray outward instead of just shooting forward as a single drop.
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Thanks for this info, great to know.
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Nice post PA4TIM and well explained Tooki :).
I'll add that a trap kit for the SX100 is very useful - part 6000-0212-P1 (https://paceworldwide.com/sx-10090-glass-fluxsodr-trap-kit). It reduces the need to do maintenance in the middle of a job by adding two extra reusable traps. Since they only take a few seconds to swap over, minimal downtime.
Regarding the Pace TJ70 thermojet I think it's a bit more flexible than the TJ85 as it has both button and optional foot actuation. Considering the small tip is 1.5mm (and flat tips are 6-7mm by 2mm) it's really a precision tool and not suitable for larger package removal. As smd keeps getting smaller anyway it's quite handy as long as you are prepared to use preheating. Perfect combo for me is a hot air station with custom profiles to fully control bga rework along with the thermojet for small jobs.
As you mentioned PA4TIM, the design of the older Pace handpieces allows you to machine/craft a custom tip if required. That is one area where cartridge tips are less flexible. Having Sensatemp wired handpieces has a side benefit that there is a larger range of stations.
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I am just about to publish a review video on the proskit SS-331 desoldering station, it goes live in a couple of hours or so:
https://www.youtube.com/watch?v=o_OKRknuoCM (https://www.youtube.com/watch?v=o_OKRknuoCM)
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The SX-100 and SX-90 handpieces are practically identical. They use all the same spare parts, and other than the change in the color of the printing, I am unaware of any actual difference. (I spoke with Pace on the phone and asked, and the guy said there are only tiny differences.) For all intents and purposes, they're just different revisions of the same model, and indeed, the SX-100 uses the same SKUs as the SX-90.
It's the SX-80 (which is almost identical to the SX-90 and SX-100) that cannot accept the flared-tube tips. An SX-80 can be upgraded to an SX-90 by replacing its heater assembly with an SX-90 heater. (Note that SX-90 heaters come in two types, with different headers, black or blue, connecting the handle to heater.) SX-80 tips are similar to SX-90/SX-100 tips, but less heater contact and without the flare. The SX-70 (still available!) uses tips that have no tube and are not compatible with any later model. See the attached image from the SX-100 manual (which, other than its title, is identical to the SX-90 manual.)
Anyhow, according to Pace, the idea behind the flare is for the airflow to cause the solder to spray outward instead of just shooting forward as a single drop.
Thanks a lot for the info, I just scored a good deal on an ST-125 station with SX-80 handpiece. A couple of users on EEV and elsewhere said that they felt like the SX-80 would clog too easily, so if I find that to be the case I will be looking into the doing the SX-90 Frankenstein mod you mention. I have a full complement of new filters and FLUX/SODR capture consumables on order, so I am optimistic that'll be a help. I may just convert to the SX-90 anyway since the eBay kit only has one tip, and if I am going to be buying new ones, I might as well get the later improved ones. Then again, I have been using an iron + blue plastic manual sucker for decades, so I think that this will be a real revelation for my desoldering adventures no matter what!
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I built my own vacuum desoldering station out of a Weller DS227 desoldering head and when removing DIPs, they just fall out of the board. But this depends on being able to apply enough heat which is difficult with boards that have heavy ground and power planes.
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Now that there are some SX-100 users to ask - mine has the odd habit to push out a bit of air before sucking. Which does not really help when desoldering.
I already checked (and disassembled) the pump in my ST station, everything seems fine. Unfortunately, the spare seals seem to be unobtainable in Germany (though they look OK and I cleaned them very well).
Any ideas how to solve this (this seems to be design-related to the rotary pump mechanism, but I don't remember it doing this a couple of years back...)
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The SX-100 and SX-90 handpieces are practically identical. They use all the same spare parts, and other than the change in the color of the printing, I am unaware of any actual difference. (I spoke with Pace on the phone and asked, and the guy said there are only tiny differences.) For all intents and purposes, they're just different revisions of the same model, and indeed, the SX-100 uses the same SKUs as the SX-90.
It's the SX-80 (which is almost identical to the SX-90 and SX-100) that cannot accept the flared-tube tips. An SX-80 can be upgraded to an SX-90 by replacing its heater assembly with an SX-90 heater. (Note that SX-90 heaters come in two types, with different headers, black or blue, connecting the handle to heater.) SX-80 tips are similar to SX-90/SX-100 tips, but less heater contact and without the flare. The SX-70 (still available!) uses tips that have no tube and are not compatible with any later model. See the attached image from the SX-100 manual (which, other than its title, is identical to the SX-90 manual.)
Anyhow, according to Pace, the idea behind the flare is for the airflow to cause the solder to spray outward instead of just shooting forward as a single drop.
Thanks a lot for the info, I just scored a good deal on an ST-125 station with SX-80 handpiece. A couple of users on EEV and elsewhere said that they felt like the SX-80 would clog too easily, so if I find that to be the case I will be looking into the doing the SX-90 Frankenstein mod you mention. I have a full complement of new filters and FLUX/SODR capture consumables on order, so I am optimistic that'll be a help. I may just convert to the SX-90 anyway since the eBay kit only has one tip, and if I am going to be buying new ones, I might as well get the later improved ones. Then again, I have been using an iron + blue plastic manual sucker for decades, so I think that this will be a real revelation for my desoldering adventures no matter what!
Nice!
FYI, the SX-80-to-90 isn’t an underground mod, it’s a sanctioned upgrade that Pace pushed at the time. :)
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Now that there are some SX-100 users to ask - mine has the odd habit to push out a bit of air before sucking. Which does not really help when desoldering.
I already checked (and disassembled) the pump in my ST station, everything seems fine. Unfortunately, the spare seals seem to be unobtainable in Germany (though they look OK and I cleaned them very well).
Any ideas how to solve this (this seems to be design-related to the rotary pump mechanism, but I don't remember it doing this a couple of years back...)
1. The air movement is created by the station, not your SX-100 handpiece. So solving this requires us to know what station you’re using it on.
Farnell carries a fairly good selection of Pace parts. But if not, why not just look on the Pace website for their distributor in Germany? If I can easily get parts from their distributor in Switzerland, then you absolutely will be able to get them from their German distributor. And as a last resort you can always order from Pace directly and have it sent from USA.
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1. The air movement is created by the station, not your SX-100 handpiece. So solving this requires us to know what station you’re using it on.
Farnell carries a fairly good selection of Pace parts. But if not, why not just look on the Pace website for their distributor in Germany? If I can easily get parts from their distributor in Switzerland, then you absolutely will be able to get them from their German distributor. And as a last resort you can always order from Pace directly and have it sent from USA.
It's a ST 115; from the parts list, it seems the pump is the same in almost all (all?) stations and did not change for a loooong time.
As this is my private equipment, I need to purchase the parts on my own; distributors didn't bother to reply to my requests, "soldering24" obviously has the rebuild kit, but charges an arm and a leg, which is unacceptable.
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1. The air movement is created by the station, not your SX-100 handpiece. So solving this requires us to know what station you’re using it on.
Farnell carries a fairly good selection of Pace parts. But if not, why not just look on the Pace website for their distributor in Germany? If I can easily get parts from their distributor in Switzerland, then you absolutely will be able to get them from their German distributor. And as a last resort you can always order from Pace directly and have it sent from USA.
It's a ST 115; from the parts list, it seems the pump is the same in almost all (all?) stations and did not change for a loooong time.
As this is my private equipment, I need to purchase the parts on my own; distributors didn't bother to reply to my requests, "soldering24" obviously has the rebuild kit, but charges an arm and a leg, which is unacceptable.
Well then now you’re just being silly. soldering24.de wants €16+vat and 7€ shipping. That seems entirely reasonable for something that sells for $15 plus tax plus shipping in its home country of USA.
So just order some supplies (like tips and filters, fresh seals for the handpiece, etc) at the same time to make the shipping worthwhile.
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Hakko 808 is a good one
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Both my MBT250 and 350 sometimes do that. The 350 is new, the 250 over 25 years old but the pump is still in mint condition after very heavy use. I used the SX70 on the 250, a few years ago upgraded to the SX100. The 350 has a SX90, both bought new so it has nothing to do with wear
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You guys aren't attaching to both the snap vac and pressure port at once are you? On my Pace MBT350 I just leave one tool air hose attached (it mentions this in the manual for performance) and leave the control on full airflow by default.
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#23 Reply
Posted by coppercone2 on 26 Jun, 2021 18:45
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i do not like those needles from the videos
That is a preposterous demonstration.
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Thanks Shock, I did not know.
I have a TJ85 and a SX90 on the 350 I wondered if I could let both connected at the same time. I tried both situations but it does not seem to differ in performance for the SX90, nor for the TJ85 (and the SX90 with the 931 nozzle.) I have not looked inside yet. From the 250 I knew I must keep the output clear because the pump outputs all its air through that port and in case of a TJ all the air sucked in by the pump goes through the vacuum input and if the SX100 uses the smallest nozzle this must restrict the air. But I was not sure for the 350 because the manual from the CD does not tell this. If I remove the SX90 when I use the TJ85, the pump is very loud, not really comfortable (not a problem because the TJ is only for doing shrinck-tubing or removing/soldering a resistor or so, when I am trouble shooting/repairing because it is silent when not in use). The TJ is not a replacement for a real hotair-station but it was able to remove resistors from a computer mobo and an 8 pin smd IC from a 4 layer PCB.
Shock, do you have a link to that manual ?
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Just checked, it's in the Pace SX100 handpiece manual.
https://paceworldwide.com/manuals
NOTE Insure that only one air handpiece is connected to either the Vacuum Port or Controllable PRESSURE Port at one time. Attachment to both ports simultaneously will cause a deterioration of performance.
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Other members are already covered all the necessary points. ;D
I personally use PACE system (a PACE MBT-250 primarily, with PS-90, SX-70 & TJ-70 hand-pieces, do have SX-80/SX-100 as standby.) & my experience with it is great so far (I used manual desoldering pumps before getting this system.), I don't do a lot of desoldering work though. PACE video on desoldering mentioned earlier in this thread is extremely helpful indeed. Forum members Shock & PA4TIM have already covered PACE systems well enough.
From my experience what matters are (at least for the PACE system I've),
1. Correct size of the desoldering nozzle/tip
2. Proper tinning of the tip
3. Addition of extra solder to the joint if necessary
4. Delayed actuation of the vacuum pump (1s or 2s after touching the joint; once the solder is melted)
5. Circular motion of the nozzle while desoldering
6. Little bit 'Wiggling' of the pin before removing the nozzle from the joint
I had to remove IR Rx/Tx diodes (PTH component) while repairing my Agilent U1241B (dense smt components near the joints) & above points made the work a breeze.
I keep only one 'Air-Hand-Piece' (SX-70 or TJ-70) connected to MBT-250 at a time.
On a side note, once I had a peculiar & rare issue (now solved) with my TJ-70 hand-piece, I've described it in this thread, https://www.eevblog.com/forum/repair/curious-case-of-pace-tj-70/ (https://www.eevblog.com/forum/repair/curious-case-of-pace-tj-70/). Aaron from PACE Worldwide kindly obliged to respond & provided some valuable inputs on construction of theses hand-pieces. Interested people may have a look.