dead microwave

Uh Huh.

Yep

Controllers are usually replaced not serviced.

Because your health depends on you knowing what you are doing. What price are you willing to see yourself and others possibly pay for a more friendly message?

"I don't get no respect!"

Why not start by simply cleaning up everything? The only thing you might have to worry about is electrostatic discharge damaging the controller or other electronic components.

I would suggest some naptha and a soft brush to dissolve the grease and clean the board. Do NOT use soap and /or water!!!! After everything looks clean and nice, let it sit overnoght before you plug it back in. That gives time for things to dry out reasonably well.

Surely, the most fundamental first move is to take a meter to the power supply, and see if there is at least some supply to the system control micro etc ? The fact that it's covered in grease may well be neither here nor there as far as the fault goes. Oils and greases are not known for being particularly conductive or corrosive. Dead is a positive problem, and one to which basic faultfinding techniques should be first applied, before going off on an 'if-then-maybe' exercise ...

Arfa

I'd normally agree, but the fact the unit /slowly/ declined suggests that something other than a voltage loss is going on.

Of course, it takes just a few seconds to check the voltages. Couldn't hurt.

That is an odd warning. Microwaves should just state "you will die if you open this, even if it's unplugged.

Well, not really. Analogue power supplies, such as the ones in microwave ovens usually are, will die gracefully as a result of bad electrolytics getting worse.

Arfa

I've never seen this, but I sure don't know everything. Anyhow, what about the fact that some buttons "failed" before others? (That's a rhetorical question.)

Understood a rhet question, but I guess it still might need an answer for others following the thread.

If a supply that's feeding a logic device such as a microcontroller becomes 'dirty' - that's either with excessive ripple from an analogue supply, or hash from a switch mode supply, and both cases potentially caused by a failing filter cap, - then operation of the micro can become 'flaky'. This can take the form of odd / unreliable behaviour, incorrect reset at power up, incorrect operation of any connected displays, and wrong operation of connected peripherals such as keypads, fault sensors etc. This is particularly true of devices which use A-D converter inputs with a ladder of resistors connected between buttons, to sense which button has been pressed, although it can also occur with matrix driven / sensed keypads.

Arfa

The microwave as I understood was above a stove and was probably cleaned frequently because of its location. I've seen many control panels permanently damaged by cleaning fluids on not only microwaves but also other home appliances and electronics. This fact can certainly account for button failure.

Agreed. I was just thinking of a scenario that would account for both progressive failure of buttons, and then ultimately (apparent) total failure of the unit to operate at all.

Arfa

Total failure as in front panel function could easily result from cleaning fluids, corrosive cooking vapors, condensation etc.. I don't recall if the OP mentioned the interior light working when the door was opened.

Excellent point about the interior door/light, that is usually a combination of microswitches and a relay contact from the controller so the light goes on if the door is opened or if it is cooking.

"Arfa Daily" wrote in news:PXhuo.1843$ snipped-for-privacy@newsfe29.ams:

grease infiltration into the keypad could be the first problem,and then grease making a conductive path and the HV shorting out and blowing the line fuse.

I finally "retired" my 30 year old,$350USD Sharp MW,replaced it with a $99 GE from Wal-Mart;1.8Cu.Ft.,1100W. Had to return the first one,the turntable didn't turn....

then I realized how much the power had dropped on the older 700W Sharp. ;-)

I don't expect the GE to last half as long as the Sharp did.

If it has GE on the front, you'll be lucky to make it past the first year. ESPECIALLY if you bought it at Wal-Mart.

My GE over-the-cooktop microwave is 11 years old, gets near-daily use, and is a-working still.

That's because it IS 11 years old. The reference was for the new ones being sold at Wal=Mart.

Jeff

I still have one of the last made-in-the US Littons, which I can pull out if the GE fails.

Does anyone make a really good, reliable microwave?

PS: There's a classic MAD spoof showing an Appalachian family (is that sufficiently PC) around their washing machine, which has been converted for alcohol production: "Our Mayjag is 18 years old, and it's a-working still!"