Question about Microwave Ovens

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Wont power on

Found one fuse on a board replaced it (20amp 250 volt) still nothing

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  • Microwave Ovens Master
  • 8,872 Answers

A microwave can be dead for many reasons.

It may be the fuse, which is usually located behind the grille or on the floor of the oven 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 TCOs or thermostats, if it has a hood fan thermostat, that should read open, as opposed to the others, which should read closed.

The TCOs you need to be concerned usually with have all black or white wires only. Please reply with photos if you have questions.

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 (or GFI) 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.

There should also be a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting & testing.

You can usually find helpful exploded view diagrams and order parts by entering your full model number here.

If you don't find yours, Please reply back with your brand and model number so we can help you.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Posted on Sep 16, 2008

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1 Answer

I have a microwave JVM3670SK06  ge what amp fuse does it use


I found a good site to find parts for the microwave. It has the fuse for $7. GE WB27X10388 Line Fuse PartSelect
Here is another search form different sellers.
WB27X0007 GE Microwave Ceramic Fuse Replacement

The fuse info
Specifications:
  • 250 Volt.
  • 15 Amp.
  • Type: Fast Blow.
  • Approx. 1.25"L.

Oct 18, 2015 | GE Microwave Ovens

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We have magic chef Over the Range Microwave Oven Model: MCO153U. Microwave was dead and no power


The original problem, was probably caused by a bad door switch along with the fuse, now there is a good chance the control panel is damaged, you will need a professional to assess if the item is worth fixing.

Apr 21, 2012 | Magic Chef Microwave Ovens

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Is there a design change for the 20amp[4amp ceramic minifuse in- line holder] to just using a regular 20 amp 250 volt fusetron?


You can use a regular glass fuse as long as it's rated the same and fits the holder. Microwave ovens use a ceramic fuse to prevent the possibility of little pieces of glass under the cover if the fuse should break. But other than the body the fuses are the same.

Apr 19, 2011 | Whirlpool MH3184XP Microwave Oven

1 Answer

Microwave will not come on, just dead. any suggestions? We cannot find our manual


There is a ceramic fuse inside (automotive style fuse) which may blow in the event of
a power surge or failing magnetron. These are available at most radio shack or
appliance parts store for a couple of dollars. Make sure to unplug unit before removing
cover and be very careful around the capacitors as they can retain a high voltage
similar to an electric fence. The fuse will be ceramic with metal ends , replace with
equal value amps and volts (stamped on metal bands at each end) for example
5A 250 V is read as 5 amps at 250 volts. These are slow blow fuses and cannot be
replaced with just automotive fuses . Hope this proves helpful

Feb 27, 2011 | Microwave Ovens

1 Answer

Where is the fuse located?


If the model number is correct, there is a small input line filter board with a 125V, 20 AMP line fuse inside the microwave. Its usually mounted on a small input line filter board at the point where the power cord enters the back of the unit. You will need to UNPLUG the microwave oven and remove the exterior case to access. The case comes off in various ways depending on manufacture and model. I found this illustration at pcappliancerepair.com based on the model number you listed this question under:

http://pcappliancerepair.com/model-display.php


The line filter is listed as item 1420. The fuse will be mounted to this board.

You can purchase replacement fuses at any hardware store. You can usually purchase a box of fuses at a hardware store for just a little more than what the manufacturer charges for a single fuse. 125V, 20AMP Slow Blow fuses are recommended.

If you have any questions, or need assistance troubleshooting, please post back and let me know. I hope you find this information helpful.

NOTE: Make sure you take any resistance readings with the microwave UNPLUGGED and the component under test isolated (removed) from the circuit.

Apr 24, 2010 | GE JES1290 Convection/Microwave Oven

1 Answer

Microwave ws cooking and I heard a funny sound. Now absolutely nothing..no power..nothing..?? wont even turn on...


Ok, this may have been the in line fuse that has failed or , the high limit capacitor may have failed as well. you will need to remove the cover, if possible, to inspect the power board. the hi limit capacitor is locate in proximity of the power board as well. the in-line fuse is on the board itself, connected to the power cord wires, via solder. if the fuse is in good condition, you will need to replace the high limit capacitor. it has failed.


Jun 18, 2009 | GE Spacemaker JVM1640SJ Microwave Oven

1 Answer

GE Advantium SCA1000 will not come on


Hi!
If the fuse isn't the problem, check the door hooks and the door-release button. When these are broken, the door switch doesn't activate, so the oven can't work.

If that doesn't help then there might be a burned wire or a component that can only be found out by opening it up, which is not recommended.

Please rate the solution if you found it helpful.

Thanks
Rylee

Feb 08, 2009 | GE Advantium SCA1000H Convection /...

1 Answer

Whirlpool GH7145XF


Check your main breaker fuse in your panel/subpanel.

Otherwise if the inline fuse is good and the main power is good, then look at the power supply for the microwave.

Mike

Nov 09, 2007 | Whirlpool GH7145XF Microwave Oven

1 Answer

MAYTAG mmv4205aab OVER THE RANGE MICROWAVE


It could easily be a bad line fuse and/or line filter. To access you will need to unplug the unit and remove the outside case. Inside the unit, where the A/C power cord comes in, there should be a small circuit card (part #237068) located somewhere with a fuse mounted on it. This is your input line filter board with line fuse. Replace the fuse, first and see if this fixes your problem. This is a 20amp appliance fuse that you can purchase at any hardware store. Make sure you place the cover back on the unit BEFORE you plug it in. It is not safe to have this area of the microwave exposed with power applied. High potentials in the 4,000 volt range are present! If the fuse does not correct your problem, the circuit card runs about $26.00. Good luck and hope this fixes your problem.

Aug 04, 2007 | Maytag MMV1153A Microwave Oven

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