EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: Mandami on July 14, 2023, 12:17:03 am
-
I'd like to fix a washing machine which stopped working because the drainage pump got stuck. I also learnt there was some smoke (I wasn't there to confirm).
I cleaned the pump and the PCB shows some traces of smoke on the plastic above the PWM of the main motor but there are no traces of failure on the PCB itself (visual inspection).
If the machine is left off for some time (main rotary knob in O position), then when spinning the knob again no matter in what position (wash, rinse, spin) only the LEDs for WASH+600 are active (green arrows in the attached picture). It doesn't start washing and it doesn't respond to any service test.
If the rotary knob is left on some option (other than O) for some time (5-10 minutes) then, by magic, it comes back to life: you can select whatever option you want and it starts/stops as it should.
Is it possible the PSU to have some damaged and the uC doesn't power properly (or there is too much noise on the DC) but as it heats up, then everything go back in specs ? what do you think ?
-
Heat the board up to 40-50C with wifeys hair dryer and try again.