Totally dead Bosch dishwasher (SMV50C00GB/07)

[cjcharles]

Hello everybody!

Happy Saturday! During the week my dishwasher died mid-cycle (when I opened the door to add an extra plate) and showed no signs of life at all. The fuse in the plug wasnt blown, but there were no lights or responsiveness after it died.

I've finally managed to get it out from under my counter (long story but it was screwed in at the back by an idiotic builder with no access to unscrew, so took a lot of moving of my stone countertop), and have taken off the back. I was expecting (hoping...) to see a blown interference suppressor that I could replace and put it back to make it all work, but sadly all looks well on the main board. Was wondering if you had any advice as to where to start on the board? Perhaps a fuse or something on the PCB?

Im an electronics engineer (in principle), but haven't done anything for ages so whilst my theory might be ok, in practice I could do with a bit of prodding or advice from somebody with more experience!

I've attached a photo of the board, but not sure where to look next...?
https://www.dropbox.com/s/xx80zhf12viv5f2/2016-09-10 14.02.51.jpg?dl=0

Thanks in advance (and sorry for the long post!)
Chris
p.s. Any idea how to tell age of the dishwasher? Bosch model numbers are the most confusing thing in the world!

 

[footprints]

Have you checked the door interlock switch mine came adrift, as I remember it was up by the fascia circuit board somewhere.

 

[footprints]

PS have a vague feeling I had to replace the plastic interlock which was part of the door handle (easy job once you have it)

 

[JohnD]

Any idea how to tell age of the dishwasher?

The FD nr.

remember it as "factory date"

http://www.bosch-home.co.uk/identify-your-appliance.html

You will find ecploded diagrams in their Spare Parts section.

You have verified that power is being delivered to and from the switch, haven't you, and examined the wires where they bend every time the door is opened.

 

[cjcharles]

I should have mentioned there was a slight smell of burning when I opened the dishwasher. It was a very faint smell but definitely there.

I can chase the cables (presumably to the switch panel) for voltage but definitely thinking i should start with the PCB somewhere... It is an integrated dishwasher so not a handle, but there is a catch I guess. I would just expect something from lights/switches, even if the catch is broken (as opposed to nothing at all).

@JohnD Thanks very much, seems it was manufactured in June 2012, which seems quite young to have failed on me....

 

[cjcharles]

Ok, further progress, I have disassembled a bit more and found a dead resistor (hard to check continuity when it is on the board but it looks very burnt). The resistor is 1GOhm as far as my memory serves (and probably a 1Watt resistor or something), hence for that to have blown it needed a big voltage spike... (32kV...).
I can go about replacing it easily enough, but does anybody have any ideas about why it might have blown, and if there is anything else I should check/replace while I am at it?
There is also a small patch of burnt components in the bottom corner next to a switching power supply chip....
Thanks again in advance everybody!

 

[Tigercubrider]

There was a recall on some Bosch dishwashers

Mine went bang ( sound of shorting and burning) but the numbers didn't tally so I bought another

 

[cjcharles]

Hmm, you're right, I could buy a new PCB now it seems to be the cause. But something that has been frustrating me is that the only components that *look* dead, are things that cost a penny or two....