Hi there,

I had a look yesterday but when I connected the board it was working and stable.
I left it connected all night long and it hasnt failed yet... xD
I might launch a washing cycle to make it fail.
I took this opportunity to write down the voltage around these optocouplers in 'stand by' mode and 'On' mode.
I remember that before I replace the PWM IC I found flickering voltage at VCC pin.
I will try make it fail again so that I can check again for the voltage of those....

Hi Mate,

I remember checking those at the begining. If I remember well there are arround 6,7 of optocouplers at the back side of the board.
I tested in diode mode the input side (only passing in one direction) and also checked that there was no short between input and output side. However I didn't check the voltage.
I will check them tonight and revert. Thanks for the idea and don't hesitate if you have any other ones

Hi all,

I have finally received the big IC yesterday.
I couldnt wait and soldered it on the board. I repaired the two damaged traces. I have put back the two big 820 uF caps, the resistor and the bridge rectifier (after confirming again good value/behaviour).
The machine turned On but it was late (23h30). So I left it and was thinking will try a washing cycle tomorrow.
Unfortunatelly when I came back this morning the clicking noise was back on with flickering voltage.

I will try dig this further but not now as I have spent too much time on it and need...

Hi there,

So I checked the board again before doing anything.
I found that there was around 0.5v in diode mode across all pins and any direction from the bridge rectifier.
Very weird so I decided to desolder it. I tested it again and it was fine xD.
So I kept desoldering things linked to its trace to test them individualy. I ended up desoldering the two big caps and one resistor. However out of the board they were showing good values.
Back to the board I noticed that (+) trace and (-) trace from bridge rectifier were showing continuity. Following them I decided...

Hi everyone,

Thanks a lot mate for all shematcis 🤗
They are very usefull and reading them I can see that I was almost right on my understanding of this circuit xD
Yesterday I tried again to turn On the washing machine and it was still working.
I launched a washing cycle and it turned Off ( 20 min from start) and On (after 30 min maybe) then it stayed On for an hour.
Surprised I came by checking the maschine and just then motor stopped abruptly and saw a flashing light somewhere around the maschine (not sure where). Everything stopped and breaker popped....

Hi everyone,

Sorry for late reply, I spent my entire sunday fixing my car.

@[B][URL="https://www.badcaps.net/member/415001-klynstronic"]klynstronic[/URL][/B] : Well, I enjoy trying to troubleshoot and fix some eletronics in order to understand/learn and sometimes buy very low faulty product to repair them for myself. So I got some tools including a small numerical microscope but I didn't follow engineer school and therefore I only know of thing I can read and see on the internet
As for the faulty board, after spending lot of time trying to check traces...

Hi klynstronic,

Thank you for your help.
I didn't notice any bad component or sulfated/overheated traces. Therefore to my eyes there is nothing looking wrong.
I already tried to reflow some solder joint but not all (i vould say maybe 20% off all solder joint).
I did it where I think there was big load of current and heat. To be more precise around big relays and capacitors and the chip behind the huge heat sink.
But there was no improvment.

Can someone explain the main principle of power supply main boards ?
I understand there is 230v ac...

Hi everyone,

I am trying to fix a samsung washinmachine power supply main board.
I already replaced it with another one to fix the machine but i want to try understand the issue with the old board.
Therefore i hope to be able to get some help to explain what to check in order to troubleshoot.
The power supply board reference is the following: DC41-00189a
I have followed one thread ([URL]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-power-supplies-and-power-supply-design/61916-powersupply-washingmachine-relay-problem?t=67604[/URL])...

Hi everyone,

I have come by this forum while trying to get info on circuit board for a samsung washing machine.
I have been following one thread and was surprised as how friendly and cool the help provided here was.
I want to be part and try learn/improve my skills.

Hope you all the best with your electronic issues ...