Question about Sharp R-1490 Microwave Oven
My R-4H84 Sharp Carousel II microwave oven stopped working. Does it have a fuse to replace?
A microwave can be dead for many reasons.
The fuse is normally located on the floor of the chassis behind the control panel or between the door switches.
If the fuse is good, it may be an open thermostat or thermal cutout (TCO) / thermal fuse on or near the magnetron or on top of the cavity / body of the oven.
If it goes dead for a while during or after cooking then comes back on, the magnetron is probably overheating and causing the magnetron thermostat to open.
Then when it cools, it closes the circuit and allows power through again.
When checking thermostats, if it has a hood fan thermostat, that should read open, as opposed to the others, which should read closed.
If it went dead almost immediately after pressing the Start pad, that's usually a shorted high-voltage capacitor.
If it went dead a few seconds after pressing the Start pad, that's usually a failing high-voltage transformer.
If it goes dead or blows the breaker when you plug it in or open or close the door, then there's a problem with a door switch or door switch mount.
If it's intermittent or random, it may be a bad connection, usually on the control board or a loose fuse holder, or even an intermittent fuse.
You should do a continuity test on the fuse while it's in the holder (with the microwave unplugged, of course) then turn the fuse by hand or take it out and put it back in, then test it again.
If you remove the fuse, then press the meter leads against the ends, it can allow internal contact to be made and make a bad fuse appear to be good.
If you or someone you know decide to look into it, we have critical safety information and disassembly information at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk
We're happy to help and we appreciate your thoughtful rating of our answer.
Posted on Jun 23, 2008
Yes it has a fuse. I have replaced mine several times. Unplug it and carefully remove screws from back and sides.The fuse is located behind the wiring on the right side near the control buttons about 6-8 inches back. The fuse can be purchased at Radio Shack and make sure it's white ceramic. It's only $2-3.00. Part #270-1041, 20 Amp, 250 Volt Fast-Acting. Try not to handle the fuse due to oils in your hands. Touch it at the metal ends. Make sure when you replace the cover that you put it back correctly.
Posted on Oct 09, 2010
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