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

[Dickysoe]

Tried today. And fried yhe chip.
And when I tried to replace the buck IC, the pad came off.
I think I'll buy a new solder then.
Thanks All.

Will try changing the IC tomorrow. Thank you for you help. Hopefully nothing blow up tomorrow.

[DavidAlfa]

So there was another problem that blew the first regulator.
Could be a short, have you checked it?

[Dickysoe]

Honestly, I don't have a proper knowledge in electronics. 
but now that the pad got pull off. is it beyond saved?

[DavidAlfa]

Normally you can track where it went and simply solder a small wire, unless it's a very complex board (Not the case).
Are you sure you didn't solder it in the wrong orientation?
Check attached picture. Check 1 and C4 for shorts (Shouldn't).
L1 must measure like a short.

Repalce the IC again, but before powerign on, check the connections with the multimeter!
Ensure there're no shorts between the pins and there's connection with the surrounding components.
Use the multimeter in continuity mode (That one that beeps when shorting the tips).

[Dickysoe]

Pin1 of the new chip (MP2456GJ) aligned with the red dot on your mark.
I also changed the resistor according do datasheet :
7.5 KOhm to 124 Kohm
2.4 KOhm to 39 KOhm

then I connect to power source, but the unit didn't come to live.
the not long after, the new chip got burnt.
Amazing how you can trace it (mark on the pics) without a diagram.

Normally you can track where it went and simply solder a small wire, unless it's a very complex board (Not the case).
Are you sure you didn't solder it in the wrong orientation?
Check attached picture. Check 1 and C4 for shorts (Shouldn't).
L1 must measure like a short.

Repalce the IC again, but before powerign on, check the connections with the multimeter!
Ensure there're no shorts between the pins and there's connection with the surrounding components.
Use the multimeter in continuity mode (That one that beeps when shorting the tips).

[DavidAlfa]

If the recommend resistors are higher, using lower ones is rarely a problem as long as the ratio is the same.
This is mostly to reduce power consumption...
But if the IC suggest lower resistor values, this is usually to compensate for the feedback input current.
7.5/2.4=3.125, (0.8*(1+3.125)= 3.30V
124/39=3.18,  (0.8*(1+3.18)=3.34V

The difference would be only about 43mV, absolutely irrelevant.

[xfint34]

Recent purchase to Canada. Sold as KSGER T12 v2.1s . Controller board looks the same as Mindstorm88. Power supply is v2.2. I have not seen this posted before. The tip of the iron goes to PE.

The case is not grounded.

There are dabs of hot glue holding the power board in place at the corners of the board.

Edit: A couple more things to mention.
The power supply has through-hole marked PE. You can see it peeking out the capacitor on the right in my photo.
The controller board I have has a different chip markings than Mindstorm88. Perhaps both of these two are some combination of real / fake chips. Both fake? Both real? One or the other? Who knows. I don't have a programmer board myself.
The fuse is all glass. No metal end caps like I've seen every where else.

[xfint34]

CPU ID: 20036410

Does this mean it's a genuine STM32? Is there any other trickery that could be going on?

[DavidAlfa]

Apparently it's genuine, though nothing keep clones from copying that. Thankfully they don't use to.
And yeah, that marking is suspicious.
You have original firmware backups, so there's nothing to worry about if you want to test other firmwares.

[Ian Dall]

This has been a most informative thread!

I purchased a T12 from the Aliexpress "KSGER Official Store". It is a V3.1S and they make a feature of "case is grounded" which they achieve with a banana jack on the back panel linked to the IEC-C14 connector. The anodising on the case, made the earthing a bit dodgy and the iron tip was still not grounded at all. So this was my approach:

• Insert 3mm internal start washers between the back and front panels and the extrusions. To avoid gaps, I recessed the corners of the extrusion with some careful filing.  This worked well, but placing the washers makes assemble a bit fiddly.
• The earth banana jack was a normal insulated banana jack with both parts of the plastic insulating bush on the same side of the panel. I thought it better to remove the plastic altogether and add an internal star washer between the earth lug and the panel.
• There is a pad labeled PE on both the power supply board and the controller board. I soldered 2.8mm Quick Disconnect tabs to both to take a removable jumper wire.
• I also added a fixed flexible jumper from the PE on the controller board to the encoder frame. The PE on the controller board connects to the soldering iron tip.
• Place a 12mm internal star washer on the GX12 connector and the front panel.
• Also the controller board was not parallel to the front panel, so I added a washer between the panel and the encoder frame and reworked the soldering of the header pins connecting to the display board. This is just to satisfy my OCD.

This all seemed to work well [ Specified attachment is not available ] and I'm pretty confident it is at least safe!

[floobydust]

But is the tip grounded? The 24VDC common needs a PSU jumper/solder bridge on V2.05 I thought.
Photos in the thread https://www.eevblog.com/forum/repair/ksger-mini-t-12-station-doa/ show a solder bridge between pins 3,4 for this and your controller does not have it.

[Ian Dall]

Not as delivered. The tip is connected to pin3 on the GX12 connector, which is connected to the PE pad on the controller board. Adding a jumper between that and the PE pad on the power supply board grounds the tip, albeit with a relatively high resistance of about 4 ohms. I didn't include a picture of the actual jumper, but it goes between the Quick Disconnect tabs I soldered in.

[DavidAlfa]

4ohm high resistence?
Damn it can only take 60amps @ 240V, definitely useless for ESD protection 

[floobydust]

The power supply V2.05 ground jumper (quick-connect) you soldered in should connect the 24VDC(-) to PE.
The tip needs to be grounded or else it will float to weak ~60VAC due to the Y-capacitor in the power supply. You can measure it with a multimeter on ACV.

[Ian Dall]

 

The 5 ohms is OK, but I don't think the very narrow trace in the handle would handle the current until the circuit breaker tripped 

I'm thinking that is what the ELCB is for.

[Ian Dall]

The tip is definitely grounded. At the line input end, the PS board is connected to the IEC connector ground and it looks like a fairly wide trace. I measure essentially zero ohms (within measurement error lacking a 4 terminal ohm meter) between pin 3 of the GX12 connector and the mains earth. There is an extra couple of ohms from the GX12 connector to the actual tip. With the thing powered up I get 26mV AC at the tip with one multi-meter and 2mV AC with another.

The 24V -Ve is not connected to the PE on the power supply board, but it is on the controller board.

[DavidAlfa]

How could it be? Several ohms in a solid 15" long AWG26 wire directly connected to the tip case?
Try wetting the tip with some alcohol, then inserting it several  times to clean the socket connections.

[Ian Dall]

Yes, of course it is not the actual wire. Opening the handle it is low resistance (<< 1 Ohm), from the main earth, right up to the contact in the handle. With fiddling, I can get the resistance right up to the tip less than 1 Ohm, but not consistently. More typically it is 2 or 3 and up to 5 Ohms, even up to infinity sometimes!

It raises the question of how good the contacts are to the heater/thermocouple, but they appear to be a different metal than the barrel, which looks like stainless steel. Anyhow, I'm not investing any more time on it unless it proves to be a problem.

[xfint34]

I tried to make a schematic of the V2.2 power supply. I used as a template the layout from schematics made by floobydust. I'm sure there are technical errors. I don't normally do this stuff.

The circuit looks the same as the previous versions. The differences I noticed are some of the components they put on this board compared to v2.04 and v2.05. In particular the rectifier and MOSFET have a lower rated specifications in datasheet.

Bridge rectifier: KBL307 vs KBP310
MOSFET: FQPF20N60C vs CEP10N6
Y1 capacitor: JNC222M vs N222M
Optocoupler: FL817 vs PC817

The PE ground trace on the bottom side of board looks much thinner than the v2.04 board. There is no big copper fill on the +24VDC.

I don't know if these differences have significant implications on performance.

[Keeboudi]

I have been using one of these stations for a number of years on a daily basis in an audio electronics workshop. It has been reliable and works mostly fine but we have one issue: We often pick up (switching?) noise on the equipment we are working on, especially stages with high gain and am/fm receivers etc. I was wondering whether anyone else has noticed this and if there is a solution to cure it?

[RayRay]

I have been using one of these stations for a number of years on a daily basis in an audio electronics workshop. It has been reliable and works mostly fine but we have one issue: We often pick up (switching?) noise on the equipment we are working on, especially stages with high gain and am/fm receivers etc. I was wondering whether anyone else has noticed this and if there is a solution to cure it?

First of, welcome to the forum!
Secondly, do note that most T12 stations use a metal case with only partial grounding (the iron itself is grounded, but not the case) There are of course ways to address it. It might help if you'd make a video though, to make the issue more clear

[Jono434]

I wasn't sure what thread to ask this in.

Does anyone know the front panel dimensions of the cut outs?  Is there a picture or a file floating around somewhere?

I'm looking at using KSGER V2.1S Controller board for example, but mounting the GX12 connector on the rear and having the 12mm hole at the front be for a push button.  And potentially using plexiglass/acrylic for the front panel painted black on the opposite side.

The main thing is the size in mm of the display cut out.  Is it 32 X 17mm?  And also the distance from the edge of the display to the center of the encoder knob hole.  This is hard to measure when assembled, but even measuring the center of the knob would give a general idea.

In the attached image, I understand these numbers are probably wrong.. but it gives an idea of what I am talking about.

[Pfeffernuss]

Hello everyone!

I just registered here after some time of passively following your discussion about the ksger soldering stations.
Meanwhile, I own one of these stations and have some questions concerning the model with V2.2 power supply. (User xfint34 has posted some pictures of this one in posts #131 and #143.)

I will just state my questions below, hoping for some answers from you.

1. As I understand from xfint34's photos, the known issue with the heatsink overlapping the HV trace is not existent in this version, right? Also, the space between the aluminum posts of the heatsink and other traces is sufficient, right?

2. At the other end of the mentioned heatsink, there is a mid-sized electrolyte capacitor very close to the heatsink. In my case it is directly in contact with the heatsink (see photo below). Is this a problem, concerning temperature of the capacitor? Otherwise it shouldn't be a problem, to cut the fin of the heatsink, so that it wouldn't touch the capacitor any more.

3. As xfint34 already wrote, the gnd-trace on the backside of the pcb is significantly thinner than in the common versions. Is it still thick enough to ensure some security in case the soldering tip would touch a part under current?

4. As you can see on the photos of my station below, the case is already connected to PE with a relatively thin black cable. Is this thick enough, or should I use a thicker one?

5. Are there any other obvious security issues in this version of the power supply, I should fix, before using the station?

Greetings and thank you in advance.
Chris

[floobydust]

Welcome to the Forums
Sorry I did not see your post, it gets busy here.

Important - is the tip grounded to PE? You don't want the tip floating up with stray voltage, or being a possible shock hazard if the PSU insulation fails. They have no safety approvals with these PSU's. Yours looks well made (transformer insulation) but I see a lot of junk builds copying the KSGER name.

The danger with the older PSU was the PCB trace has HVDC, with the heatsink on top of it  it is also on top of secondary-side PCB traces so that's why I hit the horn. It would fail a hi-pot test.
Soldermask is not a proper insulator. At least they moved the trace over a little bit by R3 as an improvement 

I see the enclosure is PE-grounded which is another improvement. The ground wire should be thick enough to clear the fuse, it looks reasonable.
It's OK the output cap is touching the heatsink, the heatsink does not have hazardous live on it.

My second concern would be the thickness of the GND trace from PE to the 24VDC secondary side, again it needs to be high current. I don't see a wire or jumper it must be a run on the underside of the board. Maybe post a few more pics, I can draw a schematic for this V2.2-220610 PSU then.

[geonicz]

Hi everyone!
Hope someone can help me with my trouble. I've just bought one more pcb from China, cause they're like leftovers from the past and cost much less than other versions without docs, with strange controllers onboard and without ability to flash devidAlfa's firmware. So, it was a good looking choice. I had one for long enough and deividAlfa's firmware forced me buy one more. Mostly for c245 and c210 tips. It's called the "2.1S original pcb" sometimes. At least in dreamcat4's project. Here is a photo of this controller. Schematics is also there. I've flashed firmware, connected t12 tip, connected c210 tip. Everything works fine. But the problem is with the c245 tip. I don't know how to connect it to this controller correctly to work with this firmware. Don't know which traces should be cut and which resistors where should be added to support c245 tips. Maybe someone can help with it?