Blomberg 1501AAA PCB damage

[ScottyM]

I bought this machine for my mum about 7-8 years ago, as it looked well-engineered.
Today, it had it’s first failure – though it’s a big one.

The machine is plugged into an RCD socket, which I fitted in the days when she still had a wired fuse box, rather than the split-load consumer unit that’s fitted now.
She told me that the washing machine had stopped during the first part of the wash cycle and was tripping this RCD socket, but not the main RCD.

I found that several tracks on the PCB had been burnt out, primarily in the area of the door switch connector and the pressure switch connector.

I understand from reading other posts that it is likely to be the door interlock which has gone faulty to cause this PCB damage, but two other tracks have burnt out and I cannot understand why.
They are the tracks to the COIL of the motor relay (the main on/off one, not the reversing one).

I have cleaned up the PCB and repaired the damaged tracks, but before I reconnect it, I am going to check the motor and door interlock very closely.

Any advice?

Thanks,

Scotty M.

[Penguin45]

Re: Blomberg 1501AAA PCB damage

Do not plug it in until the interlock has been replaced……. Straight under the soap drawer, gets wet, boom.

You need one of THESE.

If you have repaired the tracks by overlaying wire, these will survive a subsequent bang, but more track will be blown off instead.

Penguin45.

[ScottyM]

Re: Blomberg 1501AAA PCB damage

Many thanks!

I’ve ordered one from your shop.

Scotty 🙂

[boselecta]

Re: Blomberg 1501AAA PCB damage

Put the new interlock in a plastic bag to protect it from future water damage.

[ScottyM]

Re: Blomberg 1501AAA PCB damage

I’m expecting the new door interlock arriving today, as it was sent out yesterday.
In the meantime, I removed the old door interlock and examined it.
There is no trace of water leakage anywhere inside the machine.
The interlock had a rubber cover over it, again there were no sign of water dripping onto it.

However, I decided to break open the old interlock and found that the PTC element had broken down, tracking across at mains voltage.

Also, I found that in addition to the damaged PCB tracks, 3 zener diodes had failed short-circuit.
These were:
GR26, type ZY10GP (10V, 2W). I used 1N5437B (10V, 5W) to replace it.
GR28 & GR29, type BZV47C12 (12V, 2W). I used 1N5439B (12V, 5W) to replace them.

Hopefully the controller IC hasn’t been damaged in the process.

If it actually works after all this, I’m considering replacing link wire 5 (between the function switch and camswitch) with a small-value fuse, something like 315mA, to prevent future fry-ups.

Scotty M.

Edit: The postman just delivered my mail at 17:05!

[ScottyM]

Re: Blomberg 1501AAA PCB damage

Result: My mum is happy!

All the electronics seem to be OK. I ran a couple of cold quick washes which completed successfully, so now it is running a full-cycle 90-degree maintenance wash.

Thanks,

Scotty M.

[Penguin45]

Re: Blomberg 1501AAA PCB damage

Well done 😀 .

:p45:

[Author]

Posts