Bosch Classix 6 F21 fault code (brushes replaced) but still does not operate (relay clicking periodically)

[briscaF1]

Hi all,

I've had this machine for some time, maybe 10 years or so.

I replaced the brushes some time ago as they were worn out and the machine stopped working the other day "after making a noise when spinning." It may have also tripped the house RCD.

When I got to it, there was an F21 error on it, which I believe means the motor is not operational (won't spin or maybe no current?)

I've replaced the brushes and spun the motor by hand; the brushes were in contact with the commutator OK.

Reset the F21 and put the machine onto spin.

The machine drains but then a relay clicks about every 30s for about 1-2s, which I imagine is it attempting to start the motor spinning but it does not turn.

If I leave the machine for 5 mins or so, it'll continually do this clicking. If I try on a freshen up, the machine fills but the clicking occurs with no drum movement. The motor and drum are free to turn.

I've had a meter on the exposed brush connections and there is no 240V when the relay is operating or not.

I suspect that something upstream is faulty - maybe the control board (dry joint or track blown off), relay contact etc.

What I don't understand is why there is no F21 fault code again if turning the motor on results in 0 speed.

Any ideas on what to do next? 

I'm already thinking of replacing the machine given that it's old - don't really want to be spending 90 quid on a control board etc if it may not fix the problem.

Thanks in advance for any help.

 

[KDSmith]

I've had experience with earlier versions of these motors

The fault your experiencing could be due to the thermal cutout being open circuit (it's installed in this motor), it's in the white plastic fitting near the brushes and looks like a small silver rectangular tab, it should read low ohms ie a short.

If your brushes were very badly worn and the brush copper contacted the commutator it will cause the thermal overload to pop open permanently, result dead motor

[Whitegoodshelp (Andy)]

Hi. If you replaced the brushes with non-genuine ones they could have worn down again and deposited loads of carbon dust inside the motor. That can cause the motor to trip the electrics followed by it no longer working.