[brianmn]

Re: AEG 74620 C3 error

I can’t say what started the problem but the motor looks to be damaged. I noticed that one of the brushes was chipped and maybe as the piece broke off it partially shorted something?? Regardless, the resistance across the various commutator bars is not equal although nothing is shorted or open. One of the commutator bars has what looks like a burn mark and this is where the resistance values are high (~80 ohms from this bar to either one beside it compared to 0.4 ohms between all other bars).

Also, the motor control board (?; located on the floor in the back of the machine) had a burned trace on it. After repairing the trace the washer will now power on without the dreaded C3 error!

I’m assuming I will need a new motor although I will bring it to a shop tomorrow to confirm.

This is a 14 year old machine so getting a new motor over here in Canada won’t be particularly easy. I have seen used motors that are very close in specs except for being 50Hz rather than 60Hz and AEG part numbers are nearly identical: 645307300 (50 Hz) vs 645307301 (60 Hz). These are FHP motors. I don’t know of any reason why these motors wouldn’t be interchangeable as there is nothing inherent about the motor that is specific for 50Hz. I don’t know if the tachometer would function slightly different but if spin speeds were slightly off that would seem minor. Is there some key issue that would be problematic using the 50Hz motor?

Thanks again,
Brian

[brianmn]

Re: AEG 74620 C3 error

Thanks again! The spare pump I have measures 190 ohms but it didn’t make any difference when I swapped it in. I’ve ordered a new pump regardless but I’m not optimistic it will solve the problem.

Whenever the machine is turned on I get a brief period of a normal display (program time) but it switches to C3 in about half a second. I’m hoping the control board is OK.

I’m currently doing all this testing with the machine in a state of dis-assembly (top and front are off and water pump removed but electrically connected. Can the machine be tested in this way or do I have to re-assemble each time to test?

Lastly, is there some peculiar reset process for this error. I’ve tried the typical ‘pre-wash + soak + short spin’ which always works for C9 errors but no success.

[brianmn]

Re: AEG 74620 C3 error

Martin,

Thank you very much for your help so far but I’m back for more!

The hose from the sump up to the pressure switch is clear (I can blow air through it).

I checked the resistance on the old pump and it read ~100 ohms so it seems OK. I also tried a spare pump I had but it didn’t help matters either.

I also pulled the pressure switch and it clicks nicely in response to pressure and the contacts open and close when I put a meter across the terminals and pressurize the switch. I don’t know exactly which terminals to test together but each of the internal pressure switches seem to be working.

I still have a C3 code and flashing lights. Is there a next step you can suggest?

[brianmn]

Re: AEG 74620 C3 error

I should have been more specific about the issue in my first post. The C3 error is displayed continuously and the pre-wash and mainwash lights are flashing. The 1200 rpm light is also on but that may not be part of the error code. If there is any additional info known about this code please let me know.
Thanks

[brianmn]

Re: AEG 74620 C3 error

Thanks for the quick response about the nonexistent leak sensor. I’ll focus my attention on pump and hoses.

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