cross-posted from: https://lemmy.dbzer0.com/post/36272192

My washing machine is dying in stages. It started with the same symptoms as this thread. Specifically, after filling the tub for a wash cycle, it would go straight into a high-speed spin (full of water!) for a second or two (instead of the expected slow tumble), then quit. The speculation is that the tachometer is failing.

Then the machine got worse. I now cannot even start any program. No matter what program I select, I press start and after a few second pause the start button LED just blinks. It’s a generic blunt signal of a fault. The blinks are evenly spaced non-stop, so there is no error code of any kind.

To test the universal commutative motor, I followed the linked video and took resistance measurements. All seems okay in that regard (but this is based on vague resistance ranges that are not specific to my machine). Test results:

tachometer

Expectation: any reading that is not infinite/disconnected is fine.

• (video): 70 Ω
• (my motor): 52 Ω

carbon brushes:

Expectation: should be in the range 1—7 Ω

• (video): 5 Ω
• (my motor): 3.45 Ω

field windings:

Expectation: all combinations should be 1-7 Ω

• (video): 3.5 Ω
• (my motor): pin1-2: 1.35Ω, pin1-3: 1.35Ω, pin2-3: 1.9Ω

I do not have whatever model is in that video, but my readings are in the range suggested by the video presenter, fwiw. I believe my testing is incomplete because I was expecting the tachometer to be bad based on the behavior.

Motor spin test (hotwiring)

My next move was to try to make the motor spin. There is no service manual or wiring diagram for my Beko. So I inspected the motor and derived these pins (quotes are labels on the PCB):

1 (field) brown socket → brown+white “stator M” 2 (field) black socket → purple+white “stator 1” 3 (field) blue socket → red+white “commu” (commutator) 4 (brush) white socket → purple+yellow “rotor 2” 5 (brush) red socket → green+red “rotor 1” 6 (tacho) yellow socket → green “tacho” 7 (tacho) yellow socket → green “tacho” 8 (ground) green+yellow socket → green+yellow

Someone suggested this wiring:

L → pin 1
N → pin 5
jumper connecting pins 3 & 4

I did not connect direct to the wall because I wanted to use the mechanical power button of the machine to turn on and off the motor (so I could quickly cut power if needed). So power took this path:

wall (220 VAC) → safety capacitor → mechanical button → motor (wiring redirected to motor instead of control panel)

When I switched it on, the motor spun for 1 or 2 seconds and I saw a white flash (I think) and the motor quit. I turned it off. Then tried to switch it on again. No response.

220 VAC quit coming out of the safety capacitor. Instead the voltage jumped around between 10 VAC and 20 VAC. So I thought I fried the capacitor or resisters therein. I checked the motor to see if any of the pins connected to ground (answer: no, so the motor was not harmed). Then I disconnected the safety capacitor and connected it just to mains and ground. 220 VAC was output (WTF… why does it magically work again?)

I think I’m back to the state it was in before I tried to power the motor. But I want to understand why the safety capacitor apparently flashed white and temporarily died with only 10—20vac output. I need to get to the bottom of this because I still need to test the motor for more than 1 second in a way that doesn’t cause more white flashes. Is it a bad idea to have the safety capacitor in the circuit?