AEG Lav52810 Tacho Help ?

Hi

Had some fun with this. Has been banging about, to the extent now where it has unclipped a suspension spring twice. Seems to want to go to full spin sometimes in the wash program. assume the out of balance stops this but it really goes some. Will run fine for maybe an hour, or maybe a few days, then it starts again. seems worse with towels, sometimes does, sometimes doesn't.

Had a few washers apart in the past so reasonably good. All usual stuff is OK, yes bearings are good, drains clear, pump fine etc.

This AEG is the basic non led display type, so suspect at this is basically a Zanussi/Tricity Bendix, it is fitted with the LEM type motor, so the tacho is suspect ? It has the same motor and two yellow wire coil I've seen on other websites. They suggest tacho loose, or magnet loose.

I took the motor off and notice I could wiggle the coil about 2mm, so I gently prised off the endcap took the coil out inspected everything visually and it all seems fine. When assembling it all, I've pushed the endcap on firmly and hey no movement in the coil. Could this really be the problem, or am I just dreaming ! Of course got to try it, but wondered.

Presumably if the tacho had failed I would get a continous spin or no spin situation.

Thanks in advance for help

The tacho supplies reference voltage to the pcb which in return regulates motor speed. A failed tacho can cause the motor to run seriously overspeed, possibly to the point where the commutator flies completely apart or the machine goes walkabout. Spooky stuff Check the tacho coil for continuity/resistance, if you find it set the multimeter to AC volts & spin the motor by hand & measure the output. Even spinning it by hand you should be able to generate 2 or 3 volts. If you have all the above conditions & the shaft magnet is intact/in-place then you don't have a tacho issue.

Thanks Zipper. Guess I should have checked the resistance at least.

So got it back together, done a trial (empty drum) rise, drain, spin, all OK, just running through the 1st wash cycle with two big nath towels in it !

Loose coil/magnet seems to be a common issue with this motor, so keeping my fingers crossed at the mo.

Yes, mine jumoed about 6 inches as well, worrying stuff. Apart from unclipping the connector on the side of the motor all looks unscathed. If this doesn't work any ideas what else it could be, programer ?

Tacho coils are often only held in place by a simple plastic cover with clips that fasten onto the motor endshield. It isn't by any means precision engineering. If you have the correct coil resistance and the shaft magnet is firmly in place then the problem almost certainly lies elsewhere. It could be a bad contact somewhere in the tacho circuit or a fault in the speed control module on the pcb. Difficult to say which. Post the pnc number if you require further assistance.
* BTW never run a wash with a single (or very heavy) article of clothing. Many newer machines have an "unblalace sensor" that would detect abnormal unbalance & shut down full speed spin. Older machines often don't.

Hi Zipper, no joy, suspected I wouldn't be that lucky.

PNC No is 914524015, it's an AEG 52810.

As mentioned went through drain, rinse and spin fine. When on wash cycle went through wash OK. On the rinse cycle towards the end it tried to spin, without any ramp up, belt screeched, machine jumped violently, and some water sloshed out of the powder compartment, suspect out of balance kicked in, after a few mins it tried to resort the clothes, then just tried to go straight to fast spin, and which point I stopped it.

Just seems strange on all other parts of the program the motor seems happy to ramp up, reverse etc without problems. No history of water leaks, and been fine until the last couple of months, but seems to be progressively getting worse. Really nice washing machine, so I'm reluctant to condem it.

Will check see if I can get any output from the coil with the belt off whilst spinning it over. But surely would be playing up at other points in the program if the coil was u/s ?

Generally washer is reasonably full, these are two pretty big bath towels so thought it should be OK, certainly heavy enough sodden as I've just found out !

Thanks in advance and really appreciate your time.

Unless you have a bad contact someplace in the tacho circuit I have a distinct feeling you will end up having to change the pcb to fix your issue.
Leave the belt on, take off the motor plug & check the tacho resistance. Then set your multimeter to AC volts and spin the pulley by hand. With the belt in place you ought to be able get enough momentum to generate 10v +. If you get this then there is nothing wrong with the tacho generator itself.
Have you inspected the pcb for obvious signs of damage?
A new board will set you back around 100 pounds, maybe a bit cheaper if you shop around. Perhaps another alternative to consider might be something this http://www.qer.biz/servReps.htm

Hi Zipper

Right then:-

Coil resistance measured at motor terminal block - 180 ohms

Coil output spun with belt on at motor terminal block - Max 1.2V on AC scale

Coil output spun with belt off at motor terminal block - Max 0.5V on AC scale

Coil connections on outgoing side of terminal block - 0 ohms


All measurements taken with terminal block disconnected

Checked AC output with belt disconnected as my Missues was spinning it over with the belt on and not convinced she was giving it enough welly.

Still struggling to understand if it is the coil/magnet, why it seems fine elsewhere in the wash programs, and runs just fine on the individual rise, spin ,and drain programs ? But resistance does seem high for such a small coil.

If your machine has a Sole/ACC motor then the tacho is either ftted with a 504 ohm coil or a 184 ohm coil (measured at 20C). So your 180 ohms indicate a correct value for the latter coil. However your voltage readings appear low. This might have something to do with the instrument itself or perhaps being on the wrong scale, I just don't know. Anyhow; to cut a long story short it all boils back down to the same things I mentioned earlier.
Regarding your question on why the machine washes fine but doesn't spin correctly. It works like this: Speed is finely regulated to balance the wash load when the machine goes into spin. After the machine has tumbled it goes into distribution mode, and this is where problems can occur. The drum has to build its speed from tumble (35-55 rpm) to distribution speed (85ish rpm). If this does not happen gradually, the clothes will gather at one side of the drum and create an out of balance load. Your pcb isn't functioning correctly during this process therefore you need a new one. I hope this answers your question adequately

Hi Zipper

Opened up the case and as you thought pcb has a nicely sooted up area. Hasn't trashed the tracks but gone quite well locally on both sides.

Board is an Electrolux, I think I'm going to try and get it repaired, seems a shame to can such a decent 2.5 year old machine, and worth a gamble for £29.

Been a fun weekend, my PC died, washing machine went, lost the broadband connection, oh and the petrol strimmer packed up this morning. looking forward to escaping back to work tomorrow.

But thanks and really appreciate all the help, clearly wouldn't have got here on my own.

Good you got there in the end. Shame you had your weekend trashed by more or less everything breaking down, but hey s*** happens sometimes. The important thing is to take it with pinch of good humor...tomorrow is a whole new day