Kenmore Microwave/convection oven

[MrWild]

Zactly what the title says. Didn't get the extended warranty and two years out it's not doing what it should Paid too much to toss in the trash and would like to fix it except....

There are no obvious burned parts on the circuit board. What it does is the timer goes FAST and the heat don't go at all. microwave or convection. When you hit auto on for a minute (or set any time) the clock counts down at about ten-one. The seconds whiz by like tenths, and the minute is done in six seconds. I'd replace the electronics board, but Sears doesn't sell any parts for this oven. No bulging caps or fried resisters are evident. I'm thinking a surge nailed it and fried the on board CPU.

Any ideas or suggestions would be appreciated. My ;last Kenmore lasted thirty years. It's why I bought another. This one, heh. Still shiny new looking and at $320, I sure as heck don't want to throw it away.

[smarbaga]

bummer !!
you know these things are processor controlled.
but if the cpu was not working, it wouldn't count down or display.
sorry but your situation is a real wierd one.
no idea here , but i am thinking about it.

i guess a $49 one from walmart may be in line ;-(
maybe put it on a shelf for a couple of years,
bring it out every once in a while, just to see if it fixed
itself yet........ thats what i do .... seems to work great and
it is an ongoing process, i never work myself out of a job.
good luck, if u do find the problem let me know please.
garry

[MrWild]

Inside the cover was a trouble shooting guide. Using the correct model nbr. Sears does carry parts. A new cpu pcb is "only: 89.65. I finally got a error code, and it is pointing to the thermistor. The thermistor is just $19.95. No way to check the thermistor except remove and replace. Don't see how it could make the clock do what it does.

[epineh]

Maybe its really a time machine and it makes the surrounding enviroment's time speed up a small amount...do you feel a bit older after it counts down fast?

OK sorry, been a long day

On a more serious note if it has a microcontroller maybe the crystal for this is malfunctioning somehow and generating faster pulses than it should, possibly if it has two small small caps going from the crystal to ground they could be fried, I don't know if that would cause the problem you mention but it is probably the most cheapest repair you could possibly do, something like a dollar of parts.

Careful though, lots of stored energy in a microwave PCB !

Russell.

[MrWild]

With the help of the hidden repair manual... Big sticker on the back says, "No user serviceable parts, please take to repair facility." Gosh, if you rip the cover off, in a plastic bag glued to it, is a small service and trouble shooting manual. It lists error codes and trouble shooting trees. F1 worked way down to a bad thermister. F2 worked down to a bad thermister... F3... " " F4... yada yada. Okay, ordered a new thermister and another sensor. BINGO! It is not a time warp device, I never found the Flux Capacitor.