Any opinions on the AiXun T3A?

[Ungolian]

I was thinking it was a ground loop issue.  Not necessarily with the Aixun, but maybe something else connected to your common mains.  But I doubt all 3 of you are having the same ground loop issue.  The caps in the SMPS filter out unwanted noise, and I thought that could be the problem.  But you said the power was clean. I assume all 3 of your units came from the same warehouse, and it is possible that all 3 of you got units with different hardware from the majority of people.  So that's a possibility.  You said you have two handles.  Did they both come from the same place as well?  It could also be possible that all 3 of you got handles that were part of a bad batch.  You've put a lot of work in to try and figure this out, and I'm looking at it from an outside perspective.  I'm officially out of suggestions.   

[cgf5]

My T3A T245 is from random ali seller shipped directly from China ~3 months ago. Second T245 handle was bought month later from different seller directly from China. If these handles are from same batch then many other people would have this handle also. It's not from local warehouse or anything like that. For sure country has nothing to do with this. It's just happy coincidence!

[vonionel]

Problem with high overshooting appeared immediately after firmware upgrade at version 1.23. Before upgrade, I had minor overshooting and some tips has not. I replace all the caps with low ESR Panasonic and NCC brand. I bought another T245 handle from other aliexpress seller and the same result. It's possible to be my units defective but the problem appear only after upgrade. I have two of JBC c245064 tips and both have same issue: 80-90 degree Celsius overshooting. In the past I burned a JBC 245770 clone with firmware version 1.14 because overshooting issue. From my experience firmware 1.19 was the best for my unit.

[mastershake]

i sent a few emails to see if there is a way to get firmware 1.19 back ill post back if they respond

[mastershake]

its so odd some have the noise issues with these. i had 4 here (2 are mine and 2 are an employee who bought them) and just got 2 more in today for a couple local people i know and none have any issues so far with any noise at all or anything really. and the first 4 came from 2 different sellers in china and the other 2 from an american company in ga we deal with for some phone parts sometimes. so def various places.

[cgf5]

I have two of JBC c245064 tips and both have same issue: 80-90 degree Celsius overshooting.

You have genuine JBC tips with 80-90 C overshoot? Does anyone else has such large overshoots with genuine tips?

In the past I burned a JBC 245770 clone with firmware version 1.14 because overshooting issue.

How is possible to "burn" tip with overshoot? Think about it - you set 300C or 350C, and you have overshoot 400 or 450C for few seconds. These tips are rated for continuous 450C. Thus how can 450C for few seconds hurt the tip? It could happen if the tip was already bad, but then it would fail anyway just later. Are you sure this was station's fault? What kind of temperatures are you using or seeing on display? Higher than 450C?

Generally overshoot is an intentional way how to make heat up faster. It saves your time. It improves performance. It would be nice though if Aixun did allow us to make choice - setting where you can select less or more aggressive overshoot would be awesome. Most people don't mind, but some obviously do. This setting would make everyone happy. I don't believe no overshoot is the answer since genuine stations also have overshoot so this is in fact better genuine experience than before.

its so odd some have the noise issues with these.

Yea, it's strange. With your large sample size you sure should have some noisy units.
What do you think about the output though? Do you think unit should be silent if you generating 1 kHz square wave at ~8A peaks? I would think such output would be very difficult to make silent.

[smile]

i sent a few emails to see if there is a way to get firmware 1.19 back ill post back if they respond

I emailed them few questions a few weeks earlier, no response.  With such attitude to customers the upgrade firmware feature becomes the weak link, it's nice you do not have to use firewalls like on android for it not to update and brake things.

[mastershake]

they did get back to me when i emailed a while back but it was a little while back. it took a week or more to hear from someone though

[Eltax1693]

Bought a second unit, and this time I got a dead one.
Same fault as last time. Defect inductor. An easy fix.

[vonionel]

Yes, I have genuine JBC 245064. When I burned the clone tip, unit was set to 350 degree, but for some reasons the unit drove the full power to the tip, until temperature got over 500 degree. My first thought after, was that mosfet unit got shorted , but not. Maybe the tip was faulty.

[Stefan H.]

<image of 4 handles>

Hi!

Please repeat the same picture of the 4 handles. This time all aligned and a ruler in the photo. ;-)

thx!

[ygi]

For reference, that blue T12 handle with the J02 has a 45mm grip-to-tip distance so you can guesstimate the rest. 70mm for aixun T12 and about 45mm for the 245 (you're not going to grab it by the metal ring so it only appears shorter). Pretty sure no one care about the old style 936 but that would be 80-85mm.

[Eltax1693]

I did a load test on the power supply. 24V/6A. It survived 2 hours.

[cgf5]

Survived but with 90-110C on heat sink failure of diode/mosfet is very likely (for sure with higher ambient and/or in closed enclosure). That's fine though - station would never pull such high average power for sustained period. This just confirms that the 24V output on back is bad idea and should be never used. From previous discussion we already know that 120W is likely maximum average power and the 200W figure is only for peaks thus this is expected result.

[SteveyG]

Aixun T3B is here:



PCB photo attached.

[cgf5]

Today I upgraded to 1.23 firmware and after using it for some hours I noticed something was missing - the noise! No more singing handle . Well some very muted frequency is still present but only if I listen closely - that's nitpicking - I can't hear anything in normal usage when others instruments are running. I would say now the audible output is the same as before 1.20.

I was curious, so I did scope output the same way as before, identical parameters and the output is completely different. See for yourself bellow. Now there is no ~1 kHz switching frequency anymore, instead, there are ~160 Hz pulses only. Did they change it intentionally because of noise, or it is just coincidence? I don't think there is reason to change switching frequency for performance reasons - duty cycle controls power - heater doesn't care about frequency. This confirms the noise was by design - not a fault? That it was side effect of main 24V heater power switching @ 1 kHz.

[mastershake]

anyone else have the update software keep uninstalling itself? getting annoyed lol it does like 3 updates after installing it and sometimes the last one of them fails and then it removes itself.

[Ungolian]

Yeah, I'm getting that too.  But I'm not too worried about it.  In fact, I'm probably going to just uninstall the software.  The T3A performance is identical to the JBC now, so I'd be surprised if there were any further updates.  It seems totally unnecessary.  I'm not going to put a bow on it and say we're definitively done with firmware, but if we're not, we're really close.  Nobody seems to have any complaints about 1.23, there doesn't seem to be anything else we need it to do, no point in modifying the firmware even if we could get the source code...  Really, what's left?

[smile]

Seems changing to proper sized transformer is not so bad idea I have suggested after all.

[Ungolian]

If it will fit.  Mods to the PSU are about all that can be done.  Swapping the electrolytics out for Nichicons or Panasonics is the only thing most people are going to do though.  Sure, someone could redesign the power supply, and between the online services, and people on here that have the equipment, we could get a new board for it.  But is it necessary?  As previously mentioned, it took 2 hours of sustained max draw for it to fail.  Nobody is going to use it like that.  For what it needs to do, the PSU is perfectly fine.  The electrolytics being the only concern.  I think most people are fine with it the way it is, and don't really want to spend any more time or money on it.  If someone wants to trace and mod it, by all means, do so.  I'm fine with it the way it is.   

[mastershake]

i thinking about pulling the face and using a toroidal trans i have here in another case just to see how it performs

[Ungolian]

Do you mean replacing the existing transformer with your toroid, or using a different toroidal psu to power the control board?  If it's a different psu, it probably isn't being overdriven, is limited to 120w, and will take longer to heat up.  Otherwise, it will probably perform the same.  Replacing the existing transformer might be possible, there is a decent amount of space around it.  For US/117vac primary, the Hammond 1182P12 is 3.75 inches wide by 1.63 inches tall.  The Hammond has dual primaries, so it will work at 230vac as well, but the Indel TST 120/003 is MUCH cheaper (26eur vs. 53 eur), but is 230vac only.  Both Hammond and Indel transformers are the same dimensions, but I haven't measured if there is enough room for them on the Aixun pcb, nor have I considered the mounting hardware for the toroids.

Have at it!

https://www.mouser.com/ProductDetail/Hammond/1182P12?qs=sGAEpiMZZMtXHE36kCvv35gEQEha%252BHIxIx%2FhPoNBczA%3D

https://www.tme.com/us/en-us/details/tst120w_24v/toroidal-transformers/indel/tst-120-003/     

[cgf5]

You can't replace just transformer. You need to built replacement for original PSU board. But you don't even need custom PCB, prototype PCB will do just fine. Regular power supply is just mains input fuse, transformer, diode bridge and smoothing capacitor(s).

Is possible to overdrive toroidal transformer by this much though? Original switching 120W power supply is pushing over 8A into 2.5Ω heater. Can you overdrive toroidal transformer by this much? I don't believe 120VA 24VAC transformer will give you 8-9A out. Maybe some overbuilt transformers can push 200% but I would guess average transformer will not. So toroidal transformer needs to be bigger since smaller one can't provide high peak power. Well if you want to get similar output. If you fine with lower power then 120VA could work - likely - if voltage doesn't drop too much to cause brownout.

24VAC transformer will give ~30VDC after smoothing, bit too hot I think. Perhaps 17-19VAC is better choice (~22-24VDC). VAC * 1,414 - 2x diode drop from bridge ~= VDC. Of course with no or minimal load voltage will be even higher! This calculates nominal voltage not unloaded voltage. The smaller the transformer the higher the unloaded vs nominal voltage difference.

[FransW]

Design and operating criteria and limits apply to all system elements.
Implementing weak links is not very useful.
Normally these choices are the result of efficiënt operating requirements.
Oversizing parts of the system is not very useful. Except when already available.

In these cases, the limits are set by the heating element (tip) choice
Hakko, Weller, JBC, OEM type products, etc.
Since they all are functioning along the same principles, choices are limited and simple.

Other factors like lifetime (MTBF, MTTR) are mostly depending on the user requirements.

Happy soldering,  Frans

[L-Train]

So I just got my T3A in the other day and didn't notice any noise coming from the handle while desoldering a few components while on the 1.19 firmware it came with. However, after upgrading to 1.23 I did notice slight buzzing coinciding with the power meter on the display. It's not loud enough to be concerning but noticeable in a silent room at regular soldering distance. I've attached a recording of the noise (boosted 40dB) and its spectrum with the station idling at 325C and the supplied knife tip installed. It was recorded with my phone mic directly on the handle around where your fingertips rest as I found that's where the noise was loudest. It's mainly ~166.67 Hz harmonics, in line with what cgf5 measured.

Other than that, it seems like a capable station so far and a definite upgrade from my old FX-888. Maybe Aixun can tweak their firmware to mitigate the small buzzing issue, but it's not too bothersome.

Edit: I had a bit more time with the station today and the station itself buzzes in the same manner as the handle. It's actually what's causing most of the audible buzz I hear. The handle is far fainter in comparison.