Anyone seen this - Tricity Bendix washer 850 - AW851S

[blacksheep]

Machine as subject.

Is getting on a bit now, but the drum and all that is ok so decided to try to fix. It would not spin the other week so decided to have a fiddle around. Took the belt off had a look at the motor underneath, switched it on and motor worked ? So put belt back on. All was well and wife was pleased, but I said/thought "hmmm I aint done anything really so dont be suprised if it dies!"

Needless to say it died a few days later again

I though maybe there was loose connection on motor but to be honest the plug looked fine. They only other thought is that I had given the brushes a shove.

So i stripped down motor and the one brush looked very low and the other not wonderful. If they had both been like the best of the two I wouldnt of bothered but the one was quite bad so I had a look around and got them for £9 odd.

Fitted brushes today - Has made no difference at all

So time for some more logic. There is not a lot in this machine really, so far I recognise pressure sensor (to detect if enough water in I think), heater ring terminals on back of drum, usual solenoids for water, cycle switch, motor and pump.

I have even moved the cycle switch around while on to see if anything starts a spin but nothing.

So on a spin cycle , the washing machine turns on the pump that works fine, then it should startup a slow spin but nothing, the switch works its way through the cycle so I dont think its waiting for any sensors. Detected a feed on the motor brushes, stays on for a bit then goes off as if it is powering the motor but I have not done any sort of load test (was thinking maybe a weak supply from Cycle switch?), other than that maybe fault Cycle switch not controlling the speed settings (seems a load of cable I assume control different speeds/coils in motor)?

Anyone got any ideas, thanks in advance

 

[Leccy758]

If the motor is not turning at all and assuming the brushes are making a good contact and the commutator was cleaned I would start thinking the motor triac on the timer module had failed (or the control part for it)

 

[blacksheep]

I did not clean the commutator, but the brushes did fit fine.

I have even sat there with the belt off the machine, and spun around the motor with my fingers when its at the start of the cycle to see if anything happened, I would assume at least something would happen with the motor if the commutator was dirty? I may take it off later and double check, possible covered badly in carbon?

The board does have a transistor with a large heatsink on, have not looked closed but probably the triac then. The board has got some SMT components on and not much bigger so there would have to be something more substantial to drive the motor. No modules just wired straight down to the motor.

When I said I seen a feed on it, that was with a neon-screwdriver so not really a proper test. I was thinking of a 100w bulb across it then try again (for more of a load check, what do you think?).

I have made up triac circuits in my past electronics days but not sure if a Triac can get damaged/blow and give a low current feed? but I have seen strange things like this with transistors. I was thinking do the load check first then work back to this if load wont stay on.

Thanks for your help

 

[Leccy758]

The triacs can fail to operate correctly 'I cant remember the tech answer as the bloke at work who repairs them is not in' we generally change them or swap boards to confirm.

 

[blacksheep]

Thanks for making me aware of that one.

Ok I got it working after ..

Rigged up a bulb to the brush wires to see if the Triac seemed to be dealing with any sort of load. Sure enough it would go on and off like the motor does at the start of the spin cycle.

I was going to check for any resistance across the brushes but didnt bother after. So took all the motor off again, and all the wire clips so I could really get it out for a looksy.
Simple error one of the brushes was lifted about 0.5mm odd off the commutator. There is a small nobbly bit of plastic sticking out from the front of the new brushes, so snapped them off with a plyers (done both sides although it was effecting only one). Dunno if youve seen them before (SOLE motor).

Mrs. can stop taking clothes to work and over the neighbours now lol

 

[zipper]

Edited out.

 

[Leccy758]

Lol I did say fitted correctly

Those tabs are supposed to be broken off when the brushes are fitted to allow the brushes to move freely. Even if they are bent out of the way they often foul the brush after a while causing it to stick.