AEG Microwave repair

[Radio Fixer]

This model, built in, was 10 years old when a button fell off its plastic hinge.  My wifes instant solution was "... buy a new one".  No! I fix it if I can.

   

Bought a new panel which replaces all the buttons for about £15.  Total strip to do it with about 25 screws (some 10mm and some 12mm so easy to mix them up).  Did the job and the machine back working ... for a day.  Then it blew the internal fuse which needs it turning over to remove a mains filter panel.  A genuine 8A ceramic fuse from anyone is about £12 + postage !  No! I bought a 'pack of three' clones from Ebay for £3.50 incl postage. 

This fault was the inside lamp bulb which had gone intermittent short.  Only genuine ones around for £16 + £6 quick postage.  Then its the groan of about 20 screws to take off two covers to replace.  AEG (Electrolux) have a reputation for making things difficult.   If the lamp is 10 years or so old, now I think its better to replace it anyway.

Its quite tricky taking all the thing apart, particularly the removal and replacement of the front panel but I'm wary about giving tips.  These units have HIGH VOLTAGES and a CAPACITOR that must be DISCHARGED.  Dont want to encourage folk who are not qualified to do this safely.

I would buy a Bosch another time. Browsing their Web Site I see they are providing Service Manuals now which is, I believe, an EU initiative to stop the throw away and buy new culture that has grown up around kitchen and white goods.

Gary

[Retired]

Hi,

Well done Gary; I'm in favour of fixing rather than dumping; persistence has paid off for you and now fingers crossed it's going to last for years to come.

Kind regards, Colin.

[boater sam]

Replace the lamp with a sensibly priced one and a new standard bulb holder to match?  There is nothing special about the bulbs regarding microwave energy.

[Radio Fixer]

I had thought of doing that Sam but SWIMBO wanted the oven back in use ... so ...

Would have been a £200 + repair from AEG so not too bad and the bulb lasted 10 years.

Gary

[boater sam]

There is not a lot of purpose in a light in a microwave I think.  The mesh obscures the view and its not sensible to get right up close and peer long and hard when there could be a couple of w/cm2 leakage there anyway.

A torch for SWMBO?

[joebog1]

I fixed my microwave about 10 or 12 years ago. I binned it!!!. The kids were the only ones that used it and they all left home back then.
So I bought ( thinking I was smart ) LG branded products. Thats the clothes washer and the dishwasher. The clothes washer I insured for replacement but not the dishwasher.
Clothes washer had a massive hernia within the extended warranty period, and I claimed a new one. 8KG full featured model is what I had bought. New washer is 6KG and minimum features.
Dishwasher blew the control board. I mean they are covered in some tough silicon which is nigh on impossible to remove from the top, and the whole PCB is inside a plastic tray that is filled with the same insulating goo.
Its a very good insulator of course, and insulates all the heatsinks so well the goo had all gone brown from the un escaped heat. BRILLIANT idea that one. So $320 for a new PCB. remove about 40 self tappers ( PK screws ) from the inside and drop the stainless inside down about one inch so I could get to the board. ( It cannot be removed further without removing the whole door, which is spring loaded with springs akin to a medium sized car suspension )
The edges of the stainless liner are straight off the guillotine and razor sharp!! Ask me how I know !! . Unplug about 20 connectors and remove the board which just sits on three nylon standoffs.
Replace the PCB. move forward one year. Another almighty flash behind the control panel, and that sound that every serviceman and engineer knows so well. High current arching FFFFFFFZZZZTTTTTT. We now use the dishwasher as a drying cupboard and do the washing up like its been done since year dot.
By hand. Do you ever wonder how much dishwashing liquid can be bought for the price of the machine ?? That was $1600 BTW.

Joe

[Radio Fixer]

The bulb lights up the inside of the AEG microwave very well through mesh to the inside. Everything has to work in this house, certainly in the kitchen ... Not bothered by possible miniscule microwave leakage: we are not using it all day long and staring in. Thats just another scare some are putting around.

BTW the delivery charge was well worth it to me. Ordered from Ransom spares on Fri about 1:30 pm and delivered by Evri before midway, the following day (Mon was specified as likely).

Wouldnt do without a dishwasher Joe but you have put me off LG, thanks. Our Bosch is 10 years old; works fine every day. Has had the straps replaced by me that connect to the door springs.

Gary

[Mike Watterson]

The minimum electrics for a Microwave Oven are the magnetron (a direct filament diode with a magnet and cunning anode shape), EHT capacitor, and the EHT mains transformer with an on off switch. Mostly they seem to just turn on/off on to vary the average power, so for full power and a timer you could use a clockwork 55 min timer and a relay if the electronics panel failed.

I'll leave it up to the reader to figure how to add a power knob and 555 timer to have variable power or defrost mode.

[boater sam]

The minimum electrics for a Microwave Oven are the magnetron (a direct filament diode with a magnet and cunning anode shape), EHT capacitor, and the EHT mains transformer with an on off switch. Mostly they seem to just turn on/off on to vary the average power, so for full power and a timer you could use a clockwork 55 min timer and a relay if the electronics panel failed.

I'll leave it up to the reader to figure how to add a power knob and 555 timer to have variable power or defrost mode.

A high voltage rectifier diode may well be required Mike.....................................................................................

[Mike Watterson]

A high voltage rectifier diode may well be required Mike.....................................................................................

I'd have thought so too, but the last one I dismembered didn't have one, unless it's hidden in the transformer. Maybe ones with voltage doubler need a rectifier? The magnetron is a diode.

Many schematics show a rectifier diode in parallel

But the Magnetron filament is also a diode's cathode.

The switch in parallel with the transformer primary can't be correct.