BOSCH Classixx 1000 - PSU Fault

I took the transformer apart but although I got the secondary turns (34) I failed to get the primary turns. I can figure/measure the wire gauges. So, I'm stuck now. I will try to produce a suitable transformer/component using ready available products. The original transformer was made by VOGT and looks like it was core shape E 12.6/3.7. The original core part number might have been 254 04 325 10. The former or bobbin has "VOGT 32555" on it. VOGT has been taken over by Sumida. And perhaps the current equivalent part is "Flyback/Forward Converter 1-30 Watt / E.12.6 / 3.7." Somehow I have got to work out the primary turns. I know the output voltage is 12V. I attach the schematic. Not sure if neutral is connected to ground in the washer. I'll have to check that out, but I doubt it is. Some tools at Power Integrations, who made TOP209P might be helpful.

I will contact QER to see if they have managed to find a solution when T1 becomes faulty. But, I think they will want me to purchase a whole board (Siemens 5WK51307) rather than sell me just the transformer.

By the way, VD3 I think should have 120V beside it, not 120B) Volt in Russian = вольт

Actually, what QER will do is scrap the odd board and that will be how they fix a T1 problem. Feel pretty sure. They will give you about £5 I think for a board. :-)

Hello Richard. You are one in a million perusing repairing a board in white goods. I agree QER is unlikely to sell such a small component, that's not their business model and unless they did it as a favour there's no money is supplying such a small part. But they used to offer to repair your board. It would probably make most sense to buy a reconditioned board from them with a guarantee.

Yep, I agree. Save a lot of hassle just buying a new board. (Siemens 5WK51307)

Okay. Instead of trying to wind a flyback transformer for the 12V SMPS that is on the PCB, I decided on a hack. I guess that the PSU was possibly supplying about 3W, 0r 500mA @ 12V. So, I bought a small 12v @ 450mA SMPS from Ebay. It is small enough to be fitted within the PCB shrouding. Now, I have the washer working again. However, it won't empty, but I think that is not a PCB problem. For the hack I removed all of the SMPS components except item S10 K75 varistor, thought I would just leave it in. I attach a picture of the new SMPS PCB wired to the washer PCB. I've not run this washer long, so the hack is not time proven as yet. Like I say, I've guessed the current.

Drain blockage unblocked washer now works. Assuming new SMPS holds up: Cost of hack - £5.01.

NB: IF ANYONE REPLICATES THIS HACK PLEASE NOTE YOU DO SO AT YOUR OWN RISK. I HAVE NOT CONDUCTED ANY SIGNIFICANT SAFETY INVESTIGATION AS TO THE SUITABILITY OF THE SMPS THAT I HAVE USED TO REPLACE THE ORIGINAL SMPS ON THE SIEMENS BOARD. THE ORIGINAL SMPS FLYBACK TRANSFORMER HAD FUNCTIONAL GALVANIC ISOLATION PROPERTIES WHICH WAS SUFFICIENT FOR THE CIRCUIT. THE REPLACEMENT SMPS (WHICH IS A DIFFERENT CIRCUIT) THAT I HAVE USED HAS THE FOLLOWING SPECS WHICH SHOW RATHER IMPROVED ISOLATION (BETTER THAN FUNCTIONAL):

Galvanic isolation between input and output (> 1000VDC)

Input voltage 100-250V AC

Overload protection

Protection against short

Without the need of additional cooling

I have the same PCB which I believe has a similar fault. A few weeks ago the LEDs went dim and now there is no LED life at all and the machine does not respond to anything. There is power coming in to the PCB and I noticed one component appears cracked/burned. You can see it next to the diodes and is probably a resistor.

Can you confirm which component it is and where I can source a replacement. See attached photo.

Thanks, AAK

Hi...Worn motor brushes wouldn't cause the power to go off and back on again. Worn brushes wouldn't allow the machine to complete the cycle as normal once the lights came back on either. I believe we are talking a power supply problem here. The power to the machine still is questionable as if it were an internal failing then the machine wouldn't resume the programme from where it left off. I don't doubt that after 4 yrs hard use the brushes must be getting pretty worn by now and at some stage worth checking but I don't think it the issue here.

I sent my PCB for the Bosch 1000 off to QER for repair. They changed the bad resistor which was an improvement but the board still did not work. No LEDs coming on.

I asked QER for a refund, several times, but they refused, saying they had fixed it. Well they may have fixed the resistor, possibly even the power side, but they did not check the board was fully functional. I won't be using them again. Waste of £50.

I dumped the old machine and bought a new Bosch.

They should have asked for it to be sent back to check it. They can’t legitimately say it’s not faulty without checking it again, and to be fair you can’t say it’s definitely faulty because there could be another fault in the washing machine such as in the control panel or there could be a connection fault. If they refused to have it sent back to test that’s wrong but if you refused to send it back they would be right to refuse a refund.

Hello richard, very smart solution. But I could not see the where to the leads. I tracked the leads and found that positive lead is OK but negative lead is connected to one of mains (220v neutral or line). I am a little bit confused.

Could you please clearly indicate where to input (mains) and output (+,-) connection point of transformer on PCB, If still available after years ?

Thanks, Have a nice day.