AEG L64810 wash time pausing/stopping – help needed

[wrigpm]

I am trying to diagnose a fault with an AEG L64810 type P6948647. The symptoms are that, at no particular point in the wash, (usually between main wash and rinse but has been at 1 min left!) the ‘wash time’ display goes incredibly slow! Typically it takes 15 minutes for the counter to drop by 2 minutes! Whilst it is on this ‘go slow’ the machine is not doing anything at all. There are no error codes or unusual lights. This can happen several times during the wash so can extend the wash time by 60-90 mins! Occasionally, the machine will reset right back to the beginning of the cycle.

I have had this machine to bits and checked so many things I am at a loss! Things I have tested/examined are:-

Machine approx 2 years old
Motor winding continuity and isolation
Brushes removed and cleaned (they are not worn)
Machine fills, empties, spins etc OK
Run an empty 95deg wash to clean things out
Cleaned filters and drain pump
Water level OK in drum
Heats water OK

Can anyone shed any light on either the fault or why the controller pauses like this?

Paul

[Penguin45]

Re: AEG L64810 wash time pausing/stopping – help needed

Couple of points.

1/ This not an AEG, it’s a Zanussi in an AEG box.

2/ Problem may lie in the water level control system. Sludging in the collection bell will delay the “drop out” of the pressure switch, which can “hang” the programme until the level drops.

3/ The motor brushes in a machine of this age will be pretty well worn. If too short, the drive motor may struggle for a good enough contact for the motor to spin – although it may well wash. The computer will be puzzled by this.

4/ The computer may well have a problem.

5/ The computer re-setting to the default start time of a given programme points toward a logic error…..

Can’t be more specific, I’m afraid – food for thought at least.

Penguin45.

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

Penguin45 wrote:Couple of points.

1/ This not an AEG, it’s a Zanussi in an AEG box.
Yes, not surprised AEG/Zanusi/Electrolux – all the same!

Penguin45 wrote:2/ Problem may lie in the water level control system. Sludging in the collection bell will delay the “drop out” of the pressure switch, which can “hang” the programme until the level drops.

I have checked this and it is fine. No sludge in bell. Can hear the 2 stages of the level switch change as water is drained by pump

Penguin45 wrote:3/ The motor brushes in a machine of this age will be pretty well worn. If too short, the drive motor may struggle for a good enough contact for the motor to spin – although it may well wash. The computer will be puzzled by this.

I have usually got more life than 2 years out of a set of brushes! Is that all one can expect in modern machines! Either way, I have had these off and they have at least half the travel (20mm) left. There is no sparking on the commutator either so I am assuming these are OK?

Penguin45 wrote:4/ The computer may well have a problem.

5/ The computer re-setting to the default start time of a given programme points toward a logic error…..

I agree that this could be an issue but it is quite unusual for it to be intermittent like that. The strange thing is that is does eventually recover and the timer is still running – I would expect more of a ‘crash’. Has anyone seen anything like this before?

It is more like a thermal fuse has tripped and then things cool down and then restart. However, the PCB does not have one of these on and I can’t see one elsewhere. I don;t think this is just the motor as the controller PCB no longer clicks the relays to turn the motor.

Any more thoughts?

Edited to put the quotes in the right place – difficult to follow otherwise! P45 – Mod.

[cockney steve]

Re: AEG L64810 wash time pausing/stopping – help needed

Dry joint on the board?

(assuming you’ve taken proper note of what P45 has told you)

If not, ….check the motor brushes and de-gunk the pressure-system properly.

what may SEEM logical, is not necessarily so, where appliances are concerned.

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

Thanks Cockney Steve – dry joint is one of the next things I have on my list to check!

Further observation has revealed some other features of this problem:-

Usually happens at the end of Main wash or start of Rinse but always happens on the spin part of the cycle.
Machine just starts to spin (water already drained) and as the drum speeds up something appears to ‘trip’.
As the drum slows it sounds different to normal and takes a long time to slow.
From then on the machine does nothing apart from reduce the wash time very slowly. It took 20 mins to drop by 4 mins.
Once the fault has ‘cleared’ the pump restarts and it spins again.
Last time this happened it tripped again at the start of the next spin – it must only have been running again for 1 minute or so.

Any further advice?

[cockney steve]

Re: AEG L64810 wash time pausing/stopping – help needed

Hows about you revisit the motor….OK it may have had new brushes, BUT
what about the complete constituents of the old set?????

That carbon-dust will be spread throughout the carcass, windings and insulation of the motor…….washing = water = damp…+ carbon-dust + earth-leakage….maybe enough to fool an electronic brain?

I’d wash it out with meths if an airline isn’t available,paying particular attention to the brush-holders and the commutator area.

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

OK – an update on the problem/my fixes.

I have just removed, completely dismantled and cleaned the entire motor assembly. This included separating the motor casing, cleaning the rotor, stator, brushes, tacho etc etc. I have both blown this out with an airline (yes, it was pretty bad!) and cleaned with IPA.

Just put the machine on again and the problem persists! Prior to cleaning the motor I also noticed that it does do this problem when the machine is doing the tumble action as well as the spin.

From listening to the machine it tumbles fine then all of a sudden instead of the motor/drum speeding up slowly it rapidly accelerates for maybe half a second before (it seems like) it is shut down (by the controller?) to avoid it overspeeding? After this is when the machine then sits there for 20ish minutes doing absolutely nothing!

Do you think it is possible that the controller has commanded a certain amount of power to the motor, it then ‘watches’ the tacho output and sees that it is way too high (maybe because the drive cct is faulty) and therefore shuts down the control/drive? If so then why would it wait for 20 mins! Also, why would it sometimes reset to the start of the program?

PLEASE HELP!! This is driving me mad!!!!

Paul

[Penguin45]

Re: AEG L64810 wash time pausing/stopping – help needed

Aha……! Better have a read of THIS. Otherwise you’re looking at wiring problems, usually at the connector blocks, but possible in the motor itself.

Penguin45.

[cockney steve]

Re: AEG L64810 wash time pausing/stopping – help needed

another wild guess-output triac on the board….it’s switching in the spin but not holding it, if i understand you correctly.

You have checked all the harness for continuity and firm connectors?
The tub jigging about can work-harden the wiring which then breaks INSIDE the insulation…hard to find and rare,but not unknown.
Don’t know what else to suggest

I’d assume the “hang” time is a programmed default value for a particular part of the cycle….but , really, I’m no expert on this stuff.

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

Ahh – now this is sounding more like it! However, it does still leave me with a few questions:-

The motor I have is an ACC type 20584.603, AC-EL 124617906, 480/15000 RPM. Does the article still apply as the motors listed (FHP/AEG, CESET and ZEM-SOLE) do not seem to match this?

However, it does look very similar to mine – Bloody annoying that I did not check this when the motor was apart!!!! I will have to take it apart again!

I have previously checked the feedback voltage from the tacho when it was running and all seemed well – quite linear up to 30V at 1400RPM. Of course this would have been when it was working!!!!!

Regarding the controller – presumably it applies more power (via the phase controller triac) and monitors the tacho. If it gets to full power and there is insufficient/zero tacho output then it shuts down? This seems to happen very quickly 0.25-0.5 seconds.

It seems to then freeze/go very slow for a quite consistent 20 mins and then restarts – any idea why 20 mins? Presumably the times when it resets could be the controller trying this X times (3ish?) and then resetting for safety?

I will let you know what I find in the motor when I take it apart again!!!

[Penguin45]

Re: AEG L64810 wash time pausing/stopping – help needed

Sounds like a SOLE motor – just prise the end cap off to access the magnet.

Penguin45.

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

Further update now I have taken the motor apart again!

The magnet and coil do look very similar to the ones shown (I have some photo’s too – can I upload them?) except that there is no retaining ring on the coil. Instead there are sharp lugs on the coil body to retain it. Either way, the coil was NOT pushed back and the magnet was still in place. I removed/unscrewed the magnet (although it was quite tight) and have resecured with loctite). I will wait for an hour or so for the loctite to set before trying it – but I am not holding out much hope!

I really do not think that this was the problem! I also checked out all the wiring for possible breaks and there seem to be none – it is all still in good condition.

Any more thoughts?

Paul

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

Machine has been running again and the problem STILL persists!

HELP – I am at my wits end!! 🙁 😕

Paul

[cockney steve]

Re: AEG L64810 wash time pausing/stopping – help needed

Well, you seem to be fairly well into the job (not many DIY-er’s know the distinction between Isopropanol and India Pale Ale 😆 )

I think we can safely eliminate the motor and pressure-switch circuit….that leaves the doorswitch,heater circuit and the main-board itself.

If the heater appears to work OK and cycling doesn’t appear connected with the programme”hang” we’ll eliminate that.

the fault isn’t “random”….eliminates doorswitch.

MAIN BOARD!

IF you have a “slave” board with a DC feed to the motor, it is worth checking.

You may also like to visit the REFRIGERATION forum and find the Whirlpool thread with 200-odd subscriptions.

The gist of that, is that Capacitors,both Solid Dielectric and electrolytic types, are known to fail far more readily than you would ordinarily expect……..
(especially if incorporated in sub-standard Italian circuit-boards 😉

In short, I think you’re at a component-level search……it’s possible the relay-coil has shorted-turns or is arcing across a burnout…..test-meter or ‘Scope needed.

Whether It’s worth it, is your decision…. financially, it’s not,-but you seem to be a man who relishes a challenge 😛

[wrigpm]

Re: AEG L64810 wash time pausing/stopping – help needed

OK, have been over the main board with a fine tooth comb and found ZIP!! I have changed the main triac just in case but this has made no difference! All the caps measure OK and I have checked the 5 and 12V supplies and they are good. I am really getting stuck here! I have a few questions that I would like you all to help with:-

1. Does anyone have a spare controller/main PCB that I could borrow that would work with this machine?
2. Does anyone know why the controller would ‘go slow’ like this?
3. Does anyone have a service manual for this machine that I can buy/borrow?
4. Does anyone know how to interface to the diagnostic port on the main controller?

It seems to be getting a bit worse – it now resets rather that does the ‘go slow’ more regularly. Please help – my wife is going to disown me soon!

Paul

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