Bosch WFO2050 gone crazy
We've had this washing machine for 15 years and apart from the door seal and motor brushes, it has always worked perfectly. Lately it started behaving erratically.
During the rinse cycle when it usually tries to balance the load, it revs up very quickly for 1 or 2 seconds and then stops revving altogether. This "cycle" repeated every 30 seconds and needless to say, the rinsing was not completing properly. That is issue one.
Issue two: We usually used the max 1000rpm speed during winter and 800 during summer. The spin cycle revved up and then down for a second or two and then up again. This continued until the spin cycle ended and sometimes we had to use the Spin program by itself to get the clothes a bit drier.
Issue three: This morning after two loads we put some coloured clothes - a fleecy pyjamas trousers and top, a corduroy jeans and a few small undergarments. After the machine had taken water in the drum spun at a very high speed for 1 or 2 seconds and the loudest of bangs was heard. The machine stopped and repeated this high speed drum revving after 30 seconds with the same banging.
I thought the drum's spider had broken but after emptying the drum, this turned quite smoothly by hand. I also tested for up/down play but there is only a minimal 1-2mm of play. I then tried to do a Rinse program with an empty drum (just the water it had taken in previously) and the same instant high speed revving happened and although the drum did not bang, the machine did shake. This model does not allow replacement of shock absorbers without splitting the tub.
My question is: can the load balancer or its software go haywire? Can the machine's programs be given a hard reset using some secret button-pressing combination? The link is for the video I took with the back plate removed https://www.youtube.com/watch?v=hdYjorOWIYg&feature=youtu.be
I apologise for the length and wish to thank anyone who can give me some information. Thanks.
Solution Summary
AI-generated from this discussion
This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.
Bosch WFO2050 erratic high-speed spinning traced to broken tacho wire
- The problem
- Bosch WFO2050 washing machine began behaving erratically after years of normal use. During rinse and spin it briefly accelerated to high speed, then stopped and repeated the pattern. It then started giving very short bursts of very high drum speed with loud banging, even on a rinse with an empty drum containing only water.
- Likely cause
- Loss of motor speed feedback from the tacho circuit. The accepted diagnosis was a fault with the tacho coil or magnet, wiring between the motor and main PCB, or possibly the PCB. The confirmed fault was one broken tacho wire at the motor plug, caused by mechanical stress.
- What fixed it
- Inspect the motor tacho circuit and associated wiring. In this case the broken tacho wire where it entered the motor connector was found, which explained the loss of speed control. The thread confirms the fault was identified there; the exact repair method to the wire/connector was not documented.
- Checks to try
- Drum turned smoothly by hand
- Drum checked for up/down play, reported as minimal 1-2mm
- Rinse programme tested with empty drum and fault still occurred
- Motor tacho coil/magnet and wiring suggested for inspection
- Broken tacho wire found at the plug connecting to the motor
- Parts or tools mentioned
- Tacho wire
- Motor plug/connector
- Motor tacho coil
- Tacho magnet
- Main PCB
Safety: Further diagnosis should be carried out by a suitably qualified appliance engineer.
4 Answers
Hello. There might be a problem with the tacho coil or magnet on the motor (these parts are used on motors with carbon brushes). Or a faulty connection somewhere between the motor and the main PCB. Or even a fault on the main PCB. The main suspect would be the tacho magnet on the motor. If it has come loose, or broken, the washing machine loses control of the motor. It cannot tell what speed the motor is going at. Check this article out for a bit more information about tacho coils and their magnet.
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Thanks for the info. I'll try to have a look tomorrow although I've tried to have a look at spares websites and couldn't find any replacement tacho coil for this model. All I've found are either the back parts of motors or whole motors which do not make this repair worth while. But I'll still have a look as otherwise the curiosity would keep on nagging at me.
I had a look at the machine last Friday and was pleasantly surprised to find that one of the tacho wires had broken off, due to mechanical stress (akin to bending and straightening a piece of wire until it breaks), where it enters the plug which connects to the motor.
We had actually ordered a Bosch Series 4 last Monday before I had seen your post. I was busy with work all week and had resigned myself to the fact that the WFO2050 was going to the recycling site so I thought that the motor could come in handy for some DIY project and was intent on removing it from the washer prior to replacing it. But when I found the broken wire I became both ecstatic and incredulous. At least our order did not go to waste as another member of my family was on the point of ordering a Bosch washer so we transferred our order to them.
Thanks to you and your website I learnt that there is a tacho (which on second thoughts is the same as those found on wood working routers) in the washing machines and that I had never given second thoughts as to how the equipment controls the rotational speed.
Thanks again, your help and direction were spot on.
Excellent. Many thanks for the update. It will be very helpful to others finding this topic.
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