30 year old AEG Lavamat 550 washing machine motor stopped

[yenice]

This machine blongs to my 82 years old mother. Suddenly it's main motor stopped turning one day. I opened the back and top covers. The water is filled to the middle of the glass front door. Water pump works fine to fill and to empty the machine. The electro-mechanical program switch block (programmschaltwerk in German) works and the spindle of the program switch turns. I also hear some noise coming from the electro-mechanical program switch block that should correspond to the motor left and right turning cycles. But the main motor does not move.

I took the motor out, took it apart. There is no burning smell. This is a brushless type motor. I tested the 6 cables of the motor and compared the resistance values with the manual and they are ok. The capacitor of the motor is also tested fine.

So, from here, where should I check? I need a service manual for a step by step diagnosis, but I do not have it.

Similar machines are:

AEG Lavamat Clara SL
AEG Lavamat Nova SL
AEG Lavamat Nova S
AEG Lavamat Record SL
AEG Lavamat Saphir SL

If somebody has a service manual for one of these machines, I would be very happy to have it. I can understand english, german, portuguese, spanish , so any of these languages would be helpful.

 

[sesteve]

I'm afraid I don't have a service manual for this model but the style of this machine was identical apart from the fascia layout to my mums built in Neff machine she had years ago so I'm glad you are trying to keep this one going.

My initial reaction was it must be either the capacitor or the thermal overload in the motor. I've just checked the Haynes manual and that suggests the same issues. I'm guessing if you have checked the motor connections and they are fine then that would rule out the thermal overload otherwise you'd have an open circuit. I've attached the pages in case they are of any use

Good luck
S

 

[rolls_rapide]

Could the door interlock/microswitch be faulty?

 

[yenice]

I have made a simple diagram showing the motor pins and possible combinations of the pins. There are 6 pins. I checked all pins with respect to the outer metal shell of the motor, found no continuity. Then I checks the resistance of all combinations and found the following results in my hand written table. The results are in Ohms

 

[yenice]

When I compare these results to the german specification page values that I posted above, I think they are reasonable for me to think that the windings are intact. Please let me know your evaluation. If someone needs translation of the german specs, I can do.

I also tested the capacitor as follows:
It was written on it:
16 microfarad +/-%5
500V~

I first discharged it by using a large resistance. Then my tester showed 15 microfarad. I consider this reasonable value.

I Applied the buzzer to the capacitor, I could see it charging. When I tested the voltage, I could see it was discharging. The voltage dropped slowly. So, I think my capacitor is fine.

There is a very simple door switch. If it is not pressed, nothing happens. Since the machine takes water and makes noise, the door switch is tested fine.

I now think about the pressure switch and hose may be filled with dirt or malfunction. I will check this part. It is the 3rd picture in the diagram above. German explanation is double water level controller for normal and high water levels. It has 6 power pins.

Would that part be responsible for the motor not moving?

 

[rolls_rapide]

Well if you think that everything else seems to check out fine, perhaps the faulty component is the electro-mechanical programme timer. They do have moving parts (cams, contacts) which inevitably wear out. I expect that would be an expensive part.

 

[wft2800]

One thought occurs to me, not sure if it's a good idea, but have you tried hard-wiring your motor to the mains supply, perhaps using a Variac, to see if it will spin? Might just be a timer microswitch if so...

 

[yenice]

wft2800

I thought about it but I do not have a variac and I am not sure which wires are to be connected. I have 6 wires as I explained above. I have 220V and 110 V and 7 V AC with 60 Hz at my disposal.

There is a sewing machine pedal to change the speed but it is for a low power sewing motor with brushes. Probably not suitable for this particular motor.

I have uploaded above the details of 6 poles and my measurements and motor specifications. Maybe someone could help.

 

[yenice]

"Might just be a timer microswitch if so... "

This, I did not understand

I am afraid to burn the windings of the motor by making a wrong connection by hard wiring. On the other hand, I am pretty sure about my own Ohm measurements which I gave details above.

 

[rolls_rapide]

"Might just be a timer microswitch if so... "

He means: "one of the internal switch contacts in the electro-mechanical timer mechanism could be sticking or is broken." (It has been known).

Another two thoughts occurred to me:

1: Faulty wiring loom or harness. Try checking continuity of each of the motor cables, from motor plug to timer. There's the possibility of a broken wire.

2: Corroded terminals. Possibly too much oxidation on spade connectors.

 

[yenice]

I want to thank every one of you who are helping me so far.

@ Rolls Rapide
The idea of some internal contacts being damaged of the electro mechanical control block scares me because there are many cables coming on top and bottom of it plus god knows how many moving parts are inside. Looks like an overwhelming job to handle it. But cables and connectors to check is something I had not thought so far. I added these to my to do list. Thank you.

I will travel to her house in one of the days ahead and than try some more steps hopefully.

I wish a nice weekend everybody.

 

[rolls_rapide]

The electro-mechanical timer is indeed a complicated beast, best left alone if possible.

Enjoy your weekend too.

 

[yenice]

Sesteve you were right in the very beginning of my trip on repair.
I started the wash machine by removing the belt, noticed that the motor was able to turn alone, but was weak to move the belt.

I changed the capacitor and the motor worked fine. Just as before. 32 years after it was built, the capacitor has started loosing its strength, that was all. 3 dollars of expense only.

This is a happy end. I thank you all for the effort you have done to help me. I wanted to upload a video of it running, but the forum system only allows pictures.

 

[sesteve]

Well done. I'm glad you got this sorted and here's to lots more washing from the AEG

S

 

[wft2800]

Glad to hear it! My comment about the timer was idly wondering whether the electrical contacts in the timer had become corroded and needed cleaning.

If you want to show us a video, people here just upload the videos to YouTube and post the link on the forum.

 

[rolls_rapide]

"I changed the capacitor and the motor worked..."

Good stuff - a simple repair.

Hopefully it'll last another 32 years.

They certainly don't make them like they used to.

 

[yenice]

I was not so good with youtube, but made it with vimeo.

First, after capacitor fix. But the belt slips on pulley, needs adjustment.


Video from the back of the machine.


I checked all wire connections to pressure switch, made them more tight. No corrosion on the cable attachments. Took out the pipe to pressure switch and blew through it. No blocking. Checked the pressure switch by blowing into it. Switches made nice sounds. Then checked all wires coming to the control unit. They were all corrosion free and intact. Just the capacitor has gone weak. R.I.P after 30 years of hard work.

Now I have collected all documentation on these line of washing machines, including mine (my mother's). They are made between 1972 an 1982 in Europe. Different names have similar parts. I have all part numbers, installation diagrams etc. if someone else needs. The first page picture of the 29 pages pdf manual is attached.

 

[yenice]

Hi everyone, I am back again after more than 2 years. My mother was happy that her machine was working without problems. But now we have a problem:

Machine works normal and goes through washing cycles as before. Gets water, washes, spins and pumps out water. But when the big final spining must start, the main fuse of the house goes off. I tried a couple of times and all the same. Machine stops by a sound of electrical short, fuse blows.

I have seen instant sparks of electricity coming from electro-mechanical timer at that time. I uninstalled and opened the timer block, but inside I can not see and trace any malfunction so far. I can also detect no strange smell inside timer. There is a slightly melted connecting wire from outside the timer but the wire was intact and securely connected.

So I am puzzled now, what could cause the fuse to blow before final spin starts?

 

[rolls_rapide]

I was wondering if, when the timer clicks over to final spin, there might be a wiring harness short to earth? Are there any chafed/worn cables?

Or possibly one of the windings on the motor is short circuit. This might explain why washing and rinse-spins are okay, but when it switches to the fast final spin, an extra winding gets switched in then 'Bang!'