T12 STM32 V2.1S Soldering Station Controller - schematic etc.

[dreamcat4]

Still chasing that dream of the JCB on the cheap with a 3rd party controller such as the KSGER T12. Which personally I think is best. Just the thing with the firmware being difficult to flash because it's an ST device although i've heard that on linux its possible via OpenOCD. And also the open firmware (that is up on github)... being written for an earlier board revision which raises issues in regards to the compatibility to get it working etc. 

I also have some alternative options in that area however thanks to the efforts of this guy elsewhere on Romanian forum xDadu

Now neverminding that: if you are so inclined the PACE is a great lower-performance alternative. And there is nothing wrong with that at the price so long as you are happy with the performance that is being offered by it. However in the same ballpark is this other thing is available and I happen to think it's worth a gamble due to the supporting background evidence that it should be pretty good:

https://www.tindie.com/products/soguklehim/soldering-iron-controller-v33-for-jbc-t245c245/

Which then you get for about $40 the T245 handle on aliexpress + another $12 - $15 for a C245 tip. And whatever 24 high current DC supply. I have one also from aliexpress which is 20A which was less than $30. It's probably similar price to the pace overall. Just more of a gamble but potentially going to give you that greater JBC performance.

[mpbrock]

Getting side tracked, not ventured into STM32 dev yet, why is it “hard to flash”? Is it the STM32 or some problem on the pcb?

I’ve just sold my JBC di2860 station maybe I should of kept that  just feels like I need a cheap reliable iron in the office.

[dreamcat4]

because the st development tools on windows are notoriously convoluted and they make it far more complicated than it needs to be to simply flash some simple little mcu with a binary blob of precompiled firmware. via the st link device and its windows driver... all that crap unnecessary bs you have to put up with.  Why i also why i mention openocd open source tool. Like how complicated should it be to just write a string of bytes into the flash.

[Icelvlan88]

Hello,

Hoping someone can help me.

I believe my unit died due to ESP. I cannot be certain, but I was working with it all night. Took a break, saw a shock on the case when turning it back on and it didn't turn on.

I opened the case, saw that I'm still getting 24-26V from the power board to the controller board. Is there something else I can try it swap out on the controller board to bring it back to life? or am I better off just replacing? I saw on many forums that grounding the case is a good idea, but only afterwards...

Thanks!

[floobydust]

You could start a new thread for repair of the board.
An ESD hit to an ungrounded case is bad, it would likely arc at the encoder's pins. That is another reason to ground the case and secondary-side, to give ESD coverage.
Some versions of T12 controllers are junk because the 24V-3.3V regulator overheats and fails. The PC board copper for cooling is not there, or the regulator is a low quality chip.

[Icelvlan88]

I ended up just ordering another board.

What do you mean by the secondary side?

Is there a thread with pictures and such of all the improvements that could be made on the V2.1S?

Are there any improved 3rd party controller boards?

Thanks!

[Johnny B Good]

I ended up just ordering another board.

What do you mean by the secondary side?

Is there a thread with pictures and such of all the improvements that could be made on the V2.1S?

Are there any improved 3rd party controller boards?

Thanks!

 Sorry for the late reply but I've been rather preoccupied these past few weeks finalising my very first DIY (simple?) GPSDO and I'm currently trying to figure out why my 5 element Chebyshev LPF (to convert the 10MHz square wave into some semblence of a sine wave) appears to be defying all the known laws of Physics. 

 In case you haven't already figured it out by now, this is it! (the thread you were looking for! ). I think you'll find all you need to know if you read it from the very beginning. At the very least, you'll find some useful links to other sources of information. A visit to youtube will also prove fruitful if you enter KSGR12 into the search box - lots and lots of technical reviews to peruse. The more useful reviews tend to be in the 20 to 50 minute runtime range - save the shorter ones till after you've mined out all the reviewing goodness of the longer ones.

JBG

[MikeyG]

Hi, having just purchased a T12 station from Banggood, I found this blog and decided to follow the advice given here to make the unit safer. As noted earlier by mematyi, the latest board does not have an R10. As for the psu, rather than unsolder the heatsink to cut/file the bottom edge, I found it easier to remove the HV cap beside it and then snip the bottom edge off the heatsink. However, I noticed another trace disappearing under the heatsink opposite. This can be clearly seen at the bottom of Johnny B Good's photo 19 (many thanks JBG for extensive descriptions and photos). I measured the voltage on this trace at 141v AC (rms) - same as the trace already identified in this thread, but I have not seen any mention of potential danger from the proximity of this trace which passes beneath the other heatsink. This would be harder to fix (so have left it for now), and the heatsink would need to be removed and a bridge cut into the bottom edge.

Am I right in thinking this is a hazard too, and has anyone attempted to fix it?

[Gandalf_Sr]

Hi, having just purchased a T12 station from Banggood, I found this blog and decided to follow the advice given here to make the unit safer. As noted earlier by mematyi, the latest board does not have an R10. As for the psu, rather than unsolder the heatsink to cut/file the bottom edge, I found it easier to remove the HV cap beside it and then snip the bottom edge off the heatsink. However, I noticed another trace disappearing under the heatsink opposite. This can be clearly seen at the bottom of Johnny B Good's photo 19 (many thanks JBG for extensive descriptions and photos). I measured the voltage on this trace at 141v AC (rms) - same as the trace already identified in this thread, but I have not seen any mention of potential danger from the proximity of this trace which passes beneath the other heatsink. This would be harder to fix (so have left it for now), and the heatsink would need to be removed and a bridge cut into the bottom edge.

Am I right in thinking this is a hazard too, and has anyone attempted to fix it?

I fixed an issue with a high voltage track right under a heatsink, it's here on the previous page complete with before and after pictures.

Is the one you're talking about different?

[MikeyG]

Hi Gandalf-Sr, thanks for the response. I have fixed that heatsink issue - as I say by snipping the bottom corner without removing it. It was in doing this that I noticed a track under the opposite heatsink. I am attaching (hopefully) an edited version of Johnny B Good's photo 19 showing a blue circle around the track you identify, and a red circle around the track under the heatsink opposite. As I don't have a whopping 180 watt iron, I am not sure how I can remove that heatsink for "adjustment". I believe both tracks carry the same HV but have not traced them out.

[Gandalf_Sr]

Hi Gandalf-Sr, thanks for the response. I have fixed that heatsink issue - as I say by snipping the bottom corner without removing it. It was in doing this that I noticed a track under the opposite heatsink. I am attaching (hopefully) an edited version of Johnny B Good's photo 19 showing a blue circle around the track you identify, and a red circle around the track under the heatsink opposite. As I don't have a whopping 180 watt iron, I am not sure how I can remove that heatsink for "adjustment". I believe both tracks carry the same HV but have not traced them out.

I just got another one (my third) and, after proving it worked, I did the mod to clip the corner off the heatsink.  I have a Hakko solder removal gun which helped but a T12-K bit running at 300 C will melt the soldered posts and allow remove of the heatsink.  I looked at the area you point out but the track to it seems to come from the '-' terminal of the bridge rectifier via a 300 resistor so I am not convinced that it's an issue, what's really needed it to understand where you marked point is on the schematic.

My new one came with an updated bit holder that has a screw-on bit retainer, it seems fine.  I'll post pictures later.

[MikeyG]

You are right Gandalf-Sr, the track under the lower (in the pic, red circle) heatsink comes from the top of R6 which connects to the -ve from the bridge. The track under the upper (in the pic, blue circle) heatsink comes from the top of R3 and C7 which I think is the +ve from the bridge. Relative to GND (my measurements) both are reading about 143v AC (ie half wave mains). Are you saying the 300 ohm R6 mitigates the danger of a short to the heatsink? I think I would prefer to play safe and carve a bridge in that lower heatsink too.

[Gandalf_Sr]

You are right Gandalf-Sr, the track under the lower (in the pic, red circle) heatsink comes from the top of R6 which connects to the -ve from the bridge. The track under the upper (in the pic, blue circle) heatsink comes from the top of R3 and C7 which I think is the +ve from the bridge. Relative to GND (my measurements) both are reading about 143v AC (ie half wave mains). Are you saying the 300 ohm R6 mitigates the danger of a short to the heatsink? I think I would prefer to play safe and carve a bridge in that lower heatsink too.

I did have the thought about the resistor providing some protection but it won't do any harm to put a bridge in the heatsink.

[MikeyG]

Decided to leave this be for now. This heatsink is nowhere near anything else - unlike the one first identified which runs close to the LV circuitry. Thanks anyway.

[dreamcat4]

@floobydust suggested changes to update your 1st post:

 

Controller board H/W versions:
OLED-V3.0 (black PCB) same as 2.1S but no pump control, 6-pin OLED, no R20 battery killer, ref. designators shuffled, no resistor packs, battery on board, JBC option R0 may be fixed. Looks like a cheaper build.
2.1S (blue PCB, "RCT6" package 64pin) Very similar as "CBU6" package. Seems from same guys just modified for larger pin count CPU package, cheaper to source.
2.1S (blue PCB, "CBU6" package, 32pin) has pump control and buck-converter. JBC option: must cut R11 bridge. (maybe can hook a switch there to keep T12 handle option).
2.1S (green PCB) has pump control and SPX2954 LDO for 3.3V
2.1  (sometimes called 2.1S) has no pump control and an LDO for 3.3V, not buck-converter.
...

Also in schematic add: "AO4409" under Q1 as 2nd alternative mosfet.

Sorry for cross posting across different threads. Other post about it:

https://www.eevblog.com/forum/reviews/stm32-oled-digital-soldering-station-for-t12-handle/msg3095988/#msg3095988

[pvhoof]

I just received mine I plugged it in and after about 3 seconds the display came on, another 5 seconds and a pop it went dark. Upon opening it I found resistor R1 burned and open. I did not try to replace it yet since I suspect U2 got a blast of the 160v dc on pin 6 and I suspect for some reason the mosfet stays on.

Any suggestions on how to proceed would be welcome.

Peter

[floobydust]

I suggest to start a new thread in Repair and if you can post a pic of the power supply because there are a few variations.

[BlackICE]

Ask for full refund or replacement.

[nephilim]

Hi,

I got my T12 v2.1s a few days ago and did the recommended actions to ground it properly. I found this thread and since I haven't seen this elsewhere I would like to ask how & where to apply the following fix

-The heater and wand cable has ~4uH inductance and -ve spikes occur switching which stress the MOSFET and thermocouple amplifier. A small cap C8 is across the MOSFET to absorb this, but I added a fast recovery reverse diode across the heater.

Thanks
Torsten

P. S. Oh dear, I just read this thread again and the info is of course there already. Apologies!

[Mindstorm88]

Hi Guys , just received my T12 from Ksger on Ali, on the board it is written V2.1S but i doubt it is just a V2.1 here a picture for future reference as i have not seen it anywhere on the net.

[floobydust]

Everyone is copying everyone and confusing a model number with a PCB revision number. The "S" was the optional desoldering-pump control that has been removed.
Your board looks pretty much the same, a few changes like the 78L08 regulator U6 powering something, seems odd.
Note your mosfet Q1's soldering looks not well. Are the pins soldered OK?

[Mindstorm88]

i thought i had an original as i bought it from this store ''KSGER Official Store" , soldering of Q1 is not perfect but ok, i may redo it. the 78L08 is a pre step down for the AMS1117 3.3 . If i find time i will draw the schematic of it .

[floobydust]

The power section of the controller boards has been a struggle for years. Dropping 24VDC down to 3.3V either makes heat (linear regulator) or noise (buck converter) and the priority is of course low cost. Earlier boards overheated, failed then it settled down OK with the JW5026 buck converter - but no stock it could be the semi shortage forcing this change.

Your controller is using AMS1117-3.3 but max. Vin is only 15V, so they use a 78L08 to first drop it down. As well as the two 6R8 resistors and diode.
I would just finger check the temperatures of the parts to see if it's a decent solution. I think the 78L08 will run hot, maybe 0.5W dissipation is alot for the SOT-89 and that small copper fill. The controller board's version number is usually written on the other side, sometimes under the OLED and hard to read.

[Mindstorm88]

Yes the version is on the other side . it is written V2.1S

[floobydust]

It's the station model number "V2.1S" china confuses soldering station model number, revision number for the controller, firmware version etc. which adds to the confusion.
I hate shopping on Aliexpress because only the pictures tell you the details, ad text is a bunch of lies lol.

Your board looks like it has higher quality components, compared to many others. I can help with a schematic if you trace out the power section, the rest looks the same.

Check the soldering station is correctly PE grounded- the V2.05 power supply is not. So the tip will float to voltages too high for semiconductors, it's ungrounded which is a no-no. The "G" terminal on the controller board needs to be wired to the IEC, or PSU PE ground jumper put in. The V2.04 PSU secondary was grounded though. Check with an ohmmeter.