On Mon, 18 Oct 2010 09:34:05 -0700, Jeff Liebermann wrote:

On Sat, 16 Oct 2010 14:34:28 +0000 (UTC), Meat Plow
wrote:

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.

I was once asked to look at a heavily used microwave oven at a local
residential facility. The description was similar, but the problem was
obvious on first inspection. Long finger nails punching through the
elastometric contact keyboard. Once the protective membrane on the
front panel is punctured, all manner of liquids and gasses can cause
damage. I've seen this problem other times, where the customer doesn't
want to admit that they damaged the front panel, or somehow considers
such damage as normal. It also applies to TV/hi-fi remote controls,
printer control panels, calculators, where easily damaged flexible
membranes are used in place of hard plastic buttons.

While grease is usually non-conductive, having any grease in the various
connectors will produce lousy connections. I suspect a good cleaning,
and a low grease diet, might restore the oven to normal operation. The
green crud (copper sulfate) does not necessarily signal the demise of
the wiring, unless it's extensive. I would not replace any electronics
until the keyboard and controller cards are baptized in solvent. It
would also be interesting to determine how the grease entered the area.
Probably a mechanically mis-aligned exhaust duct.

I've seen the corruption of membrane switch panels from users spraying
things like window cleaners directly on them. Without any punctures.
While talking to the customer I try to ask how they cleaned their stuff
without trying to point blame. People don't like to readily admit to the
over zealous spraying of cleaners that can and do eventually seep into
membrane panels. I cringed in horror once watching my girlfriend cleaning
my then 2 year old GE oven, She sprayed the front with copious amounts of
window cleaner. I told her from now on she was to lightly spray it on a
clean cloth first then wipe the membrane. On everything. Not too many
realize this is a serious problem unfortunately.



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