Circuit board for problem dishwasher

Newbie · Joined: 04 Apr 2011 Posts: 3

Hello I have this simple circuit board from a dishwasher and I was wondering if anyone here can point me in the right direction as to what component can be at fault.
The problem is when the machine starts it's first cycle...adding water, it fills then starts the washing but then it starts to turn the water on and off many many times in short bursts causing my pipes to pound loudly.
I checked the voltage going to the valve and saw it was fluctuating between 9v to 0v causing the valve to open and close erratically. This leads to the circuit board causing the problem.
So the pink wire in the photo powers the water solenoid that opens and closes it. Any ideas? Here are the photos.
Thanks

tj · Joined: 24 Oct 2005 Posts: 9 Location: Denmark

When I have had this type of problems with dishwasher/washingmachine, it has always been the sensors that monitors the level of the water. It can be clogged by waterlime or dirt.

Newbie · Joined: 04 Apr 2011 Posts: 3

Hmm, I did suspect that and had a quick look at it, it seemed to be switching on and off but I didn't test when problem was occurring. I will do a live test and look for dirt etc. tonight. Will update later.
Thanks

Newbie · Joined: 04 Apr 2011 Posts: 3

Well it's not that switch because the water doesn't even get high enough to activate the switch.
So it's back to the circuit board, maybe it's timing the water flow and not adding enough, and when it registers that there is not enough it continually tries to add more. The water is free flowing as fast as it can through a quarter inch pipe used!
I tried to order another circuit board but the no longer stock them!

achmadmualip · Joined: 18 Apr 2011 Posts: 2 Location: indonesia

Thank's

Guest · Posted: Fri May 06, 2011 3:38 am Post subject:

I would be checking for poor solder joints (dry joints) on components switching the solenoid.

sj · Guest

first fault to occur would be mechanical sensors exposed to harsher environment than your pcb. Is it triggered by the cycle or the amount of time it's on and heats up. Time this: Turn off when ruckess occur by opening the door. Let cool a couple hours then restart. Find out if the is a correlation between time on or a particular activity going on inside (different solenoids and sensors activated at various times).