Our Bosch dishwasher is failing to complete a regular wash cycle and although water is pumped out if you force it through a rinse and hold cycle the water smells foul after a couple of days.
30Jan06 @ 12:50
I called APE electronics in Santa Rosa and find that a new heater for this unit costs about $107 and a new control panel about $206 - yipes.
I took the dishwasher out of its mounting hole and turned it upside down and pulled it apart and disconnected the heater unit, which has a temperature sensor in it and a pressuer sensor connected to a microswitch as well as the heater element. I tested the pressure sensor by blowing into the (sealed off by my hand)s heater element with a continuity meter across the microswitch contacts. That works OK when you put on pressure and then a little more (by blowing with the mouth).
The temperature sensor, a.k.a. NTC thermistor, seems to be working fine too when tested in hot water, i.e. it's resistance decreases from about 5k ohms to 2k ohms ish. So the assumption is there is nothing wrong there. So I reassembled the base of the dishwasher after reconnecting everything and making sure the pink plastic rod connects into the cup shaped end of the lever that sits on an expanded polystyrene thick washer on the bottom of the machine, etc.
I took the front panel off the dishwasher and looked at the control circuit board and found a burnt out solder joint connecting to the big power relay on the board. Yeuk!
As I look around the flow soldered back of the bad board I notice several dry joints and several more on the board of the working dishwasher.
So I take lots of photos. Photo DSCF2940 taken 05Feb06 at 11:44 shows the board to be SIEMENS GV630 (or maybe that's GV530 - I think GV630 based on web search results). From the bottom of the board the burnt out solder joint is bottom right of the large common contact plate, i.e. the bottom of the 3 contacts one above the other on the right end of that connection "lake".
I have photos and this is what they show:
2939 top side of the board with 3 orange power relays.
2940 rear of board including burnt joint
2944 close up of burnt joint and possible other bad joints
08Feb06 @ 10:50
I called the BSH Home Appliances JP number = 800 944 2904
Which is at Dept. HPS
2800 South 25th Ave, Broadview, IL 60153
This is the number offered in the Use and Care Manual.
Their phone refers you to their online website http://www.boschappliances.com option 4 for a customer support rep. I didn't want to wait the estimated 22 minutes so left them a message with my phone and address as well as unit # = SHU4302UC/U06 and complaint that I have two of these dishwashers and want a new control board free of charge as I see a manufacturing fault.
I went and bought a replacement power relay for ZF900080 at HSC in Rohnert Park for $2.50 and took out (desoldered) the old one and tested it, only to find the old one seemed to be working fine. So I soldered it back in. It's a 12v relay. When I applied 12v to it from the new variable voltage generator I bought at HSC for $45 the Rinse and Hold and the Clean LEDs lit up on the front of the display as well as the relay closing the contact between the top right and bottom middle contacts with the 12v applied to the outer two lower contacts, with the contacts facing me in this configuration:
11Mar06 - I think
I installed the new control board I pursuaded Bosch to sell me for half price after telling them how suspicious I was they have a known problem with these boards that they are not making public. I have found quite a lot of web references to people having the same problem with these dishwashers and even photos of the same burnt out solder joint.
I then tested the dishwasher only to find that it will not pump out any remaining water or start a wash cycle. Ugh! I wonder if that rod that inserts into the plastic cup on the base of the dishwasher is properly aligned.
This is very disappointing. I wonder if there is some kind of initialisation sequence that you have to go through to get this control board to "initialize".
Can anyone suggest, please, pretty please what I should do next to try and get this darned dishwasher working again?