Our 20 year old (1984) JC Penney microwave, model 5919-00-40, ceased to
work last night. It acted like the fuse had blown, which it had, but
that didn't cure the problem. Further investigation revaled that the
problem lies in the control pad, not the actual part that does the
cooking and can kill you. I took out the circuit board, which contains
the display, keypad, etc. and controls the microwave, and looked it
over to see if there were any obvious problems, such as another blown
fuse, which there weren't. I saw some little strips of wire on the
board in various places marked 9V, 12V, etc. and when I connected a
meter between them and the ground wire I got no reading. I verified
that the transformer was providing electricity to the board, and the
output frpm the connectors matched the values printed on the circuit
board.

By accident I shorted out part of the transformer for the board, the
10v section, and to my surprise the display lit up and the buzzer
beeped, like it would after a power failure. Then it would sort of
slowly fade out. I didn't repeat this too many times because I didn't
want to ruin the power transformer or anything.

From this, can anyone figure out what might've happened? I really don't
want to scrap this as it is so simple to repair, as far as the layout
goes.


Regards,

Tim