Is this a Hotpoint Aquarius WMS38 motor controller fault?

The machine was working fine until I found it sitting doing nothing when it should be spinning. The machine will now pump out water ok but whenever it tries to rotate the drum it always seems to attempt it at full speed. After 2 seconds and a bit of drum banging it stops and does nothing else. Any ideas what is going on?
Graham Thomson, July 2007


done
The law of sod mate!! sometimes thats all it takes Hope it works

automatic74, July 2007
Progress so far:
I read a few suggestions about tacho magnets falling off the motor but the magnet and pickup (200 ohms and 400mV when the drum rotates by hand) seemed ok. I traced the tacho route onto the board. The pulse 'squaring' transistor (marked Fp1) was suspect C-E short. The transistor was desoldered but tested ok on its own.
There are a few links marked 'Ground' and '12V' so I powered these up up from a battery and checked the 5V regulator was ok. The tacho pulses were reaching the square NEC chip at the end of the board - I think this is the brains of the outfit and probably where the problem lies.
Anyway I could not find anything obviously wrong so I put it all back together and the damn machine starting working properly!
I am about to try a full wash and give it a test.

Graham Thomson, July 2007
think you might be right with your speed control diagnosis mate. check e bay for a replacement card and timer to be sure

automatic74, July 2007
link Click here to see other fixes for Hotpoint Aquarius.