Thursday, October 04, 2012

Facts about my Dishwasher

Things I learnt about my dishwasher today:

  • It has a Mitsubishi M38503M4-722FP micro controller with 512 byte RAM and 16kByte of mask-programmable ROM, which, frankly, is quite a lot for doing the dishes.
  • There is a debug-connector with serial port Tx/Rx, GND and Vcc on the side of the controller PCB, but there's no signal on the pins it because apparently the controller is broken.
  • It has probably be killed by overvoltage, more precisely by the kind overvoltage that also made the (I assume) 7805 on the other PCB explode violently.
  • 7805 tend to explode violently if a power-relay next to it shorts, and burns through half of the PCB, and I assume it did so with a ball of conducting gas or plasma generated under the relay, feeding 230V AC to what previously was a +5V Vcc line.
  • PCBs that short and burn through half of the material make the whole kitchen stink like burnt electronics.
  • I think need a new controller for my dishwasher.









2 comments:

Pommes-1 said...

What is about dish wash in retro style with your own hands??
By the way my dish washer has also some problems...

Christian Vogel said...

That's what we currently do...