Beko WMB61631S Motor issue

[Fordie]

Hi,

my daughter has a Beko WMB61631s which recently stopped spinning. I figured it was probably the brushes so removed the motor to check, the brushes were fine but there was quite a lot of carbon all over the motor and especially around the brushes and commutator, I cleaned this up, but it still didn’t spin, I then found the motor control pcb had blown, 2 tracks were burnt out on the back and I tested the rectifier and this was bad, I figured that maybe the carbon build up had caused this, I tested the motor with my test meter and there was no short circuit or anything, I purchased a used motor control pcb from eBay and fitted it, now the motor does spin, but literally at full speed for a second or so then stops, then after a couple of minutes it spins again, but only for a second or so again. If I disconnect the motor tachometer from the main board it spins at full speed again but for longer, so I guess the main board is getting feedback from the tacho, I am asking if anyone knows if it’s possible the used board I bought is at fault, or, is it the tacho on the motor, or could it be the main board? Is there any tests I could do, I tested the resistance on the tacho and at rest it was about 90 ohms and this increased when the motor was turned.

any help would be much appreciated, I know she can’t afford a new machine right now but I don’t want to keep guessing and spend as much as a new machine on parts!

 

[Whitegoodshelp]

Hello Fordie. If the magnet inside the motor that runs inside the tacho coil has fallen off, or come loose, unscrewed or broken then the PCB loses control of the motor speed and every time motor is powered it spins.