February 25th, 2012, 11:02 AM
Why my microwave is blowing internal fuse?
Hi,my wirpool MH75XST-1 over the range microwave is blowing the internal 20 amp. fuse when i try to use the microwave function only.it doesn't blow this fuse using the fan,lights or display.Any ideas?
February 25th, 2012, 10:19 PM
is blowing the internal 20 amp
Opening the door, closing the door, when you press start?
Q - My microwave went dead when I opened the door ( same problem as closed the door ).
A - This often is a stuck or faulty door switch and it has blown the interior microwave fuse.
Q - My microwave blows the fuse inside itself as soon as I push the start button.
A - Usually a shorted high voltage capacitor...see components section.
A copy and tip from Prashanth:
Description of problem (Maytag CMV1100Q) :
Microwave stopped working while cooking. Replaced a 20AMP fuse.
When the cook cycle starts, microwave makes a groaning noise and stops. It loses power since the fuse is blown.
Solution: High-voltage capacitor shorted. Replaced it and microwave works fine.
Its located behind the fan underneath the high-voltage transformer.
Remove the vent fan hood
Remove the display control panel by removing the screw
Take pictures of all the connections behind the control panel.
Unhook all connections
Remove the connections to fan
Remove the fan
Remove the screws and connections for interlocking switches.
Make sure the high voltage capacitor is discharged!
Remove the high voltage capacitor and replace
Retrace the steps and put everything back.
Microwave works great now.
February 25th, 2012, 10:37 PM
Sorry,is doing it when i press the start button and works for 3 seconds before blows the fuse.
Originally Posted by jeff1
February 25th, 2012, 10:44 PM
Often a shorted HVCapacitor like mentioned above...
Ohm testing a cap...
Testing a capacitor
February 27th, 2012, 12:46 AM
February 27th, 2012, 07:18 AM
Do you think it’s possible that the condensation from the vapor could have caused the short in the microwave’s transformer.
HVTransformers don't go often but when they do we often see them cooked up.
I’ve been checking the prices for the transformers and they’re very expensive
No pic Transformer, h.v. Manufacturer Number 8206343
February 27th, 2012, 08:55 PM
High voltage arcs like crazy when the humidity rises, just listen to the power lines when it's foggy out. Most likely the transformer will fix it. but they are not cheap.
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