Question about Microwave Ovens

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ARE THERE INTERNAL FUSES IN MICROWAVES THAT CAN BURN OUT. MINE STOPPED WORKING ENTIRELY

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  • LARRY FISHER Aug 06, 2008

    I HAVE THE EMERSON W8107WAC MODEL MIDCROWAVE. HOW DO I TAKE ACCESS THE FUSE OR THE CIRCUIT BOARD. THE BACK PANEL WHERE I THINK IT IS LOCATED, IS ENCLOSED BY THE MAIN BODY OF THE MICROWAVE ON ALL 4 CORNERS. HOW CAN THAT PANEL BE REMOVED OR ACCESSED

  • LARRY FISHER Aug 07, 2008

    THANKYOU. YES THERE ARE SCREWS AROUND THE PERIMETER, BUT IF YOU READ MY ORIGINAL COMMENT, YOU WILL SEE THAT THE BACK PANEL IS NOT ON THE OUTSIDE OF THE MAIN COVER OF THE MICROWAVE, IT IS ACTUALLY INSIDE THE MICROWAVE AND THERE IS A METAL LIP COVERING IT ON 4 SIDES. IF I REMOVE THE SCREWS HOW CAN I GET THE PANEL OFF? IS THERE ENOUGH EMPTY INTERNAL SPACE IN THE MICROWAVE TO PUSH THE BACK PANEL INWARD AND THEN ANGLE IT OUT TO ACCESS THE CIRCUIT BOARD OR FUSE?



    THE SCREW THAT ARE USED ARE A TYPE I NEVER SEEN BEFORE (6 STAR SCREWS). IT WILL COST ME $25 FOR A NEW SCREW DRIVER TO TAKE THESE OUT. I WANT TO KNOW I CAN SUCCESSFULLY TAKE THE BACK PANEL OFF AND ACCESS THE PARTS BEFORE I BUY IT.

  • LARRY FISHER Aug 07, 2008

    Thankyou once again. I guess what you are implying indirectly is that after I remove the perimeter screws with an expensive new screwdriver, that I will be able to tilt the back panel inside the microwave to access the fuse.



    The next challenge will be realigning the screw holes since there is not much of a grip on the back panel.



    I of course will have the power disconnected, but are there any other precausions I should take? Should I short something out beforehand.



    There is no power in the microwave. The lights do not work at all.

  • LARRY FISHER Aug 13, 2008

    Hopefully this will be my last question. Once I take off the back of the microwave, are there any precautions, other than having the power off, to avoid shock. Is there anything I need to short out?

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There's usually an input line fuse on a small circuit board (part of an input line filter circuit) in most microwave ovens. This is usually a 20 amp appliance fuse that you can purchase at most major hardware stores (you would need to look at the fuse to verify the rating). You would need to remove the exterior cover to access the fuse. Its usually located near where the power cord enters the unit. Make sure you unplug the unit prior to attempting any repairs to the interior circuits. Microwave ovens are particularly dangerous as the the voltage potentials in the high voltage network are in the 3000-4000 volt range. In addition, most manufacturers provide a schematic drawing with troubleshooting advice behind the operator console, or inside the interior cabinet wall. I hope this helps you.

Posted on Aug 01, 2008

  • 1 more comment 
  • Jeff Rockwell
    Jeff Rockwell Aug 06, 2008

    There should be a series of screws around the perimeter of the outside casing that you will have to remove. Once the screws are off, the entire outside case should lift off.

  • Jeff Rockwell
    Jeff Rockwell Aug 07, 2008

    Okay...your model number is actually MW8107WAC. However, I could not find any parts illustrations for this model. However, Emerson microwaves are generally constructed in the same manner. Yes, some of these microwave ovens have special screws to keep the average consumer out of them because of the high voltage network. If you do not know what you are doing they can be fatal. The screws you mention, however sound like a torx type (Usually about a size T2). If this is the case you can by a single torx driver for less than $25.



    When you remove the outside cover of the microwave oven, the rear panel does not come off. It is actually part of the chassis. The input line filter (which is usually where your fuse is located) is generally mounted on the right hand side of the unit somewhere near the high voltage network (Magnetron, HV Transformer, HV Capacitor & HV Diode). It should be fairly easy to locate the fuse once you get the cover off. Just follow the power cord.



    Does your microwave power up at all? The reason I ask is because, if you check the fuse and it is not not blown, some microwave ovens are equipped with a thermal cutout (or thermostat) mounted near the Magnetron. It is a small silver button shaped device that acts as a fuse. If this blows, it must be replaced and will give the same indications as a blown line fuse. This is something you may check if you encounter this. I hope this helps you.

  • Jeff Rockwell
    Jeff Rockwell Aug 13, 2008

    If the oven hasn't worked and has been shut off & unplugged all this time, there should be no danger of electric shock. There is usually one large capacitor in the high voltage network that is mounted in a circuit with the magnetron. That is the only component that I know of that would hold any significant charge (if any). If you just want to err on the side of caution, however, you can fashion a home made shorting probe by taking piece of insulated wire and affix an alligator clip to one end and strip the other end to expose some bare wire. Wrap the bare wire a few turns around the shaft of a long screwdriver. Now, simply clip one lead to some bare metal on the equipment chasis, grasp the screwdriver by the handle, and touch it to the terminals of the capacitor. This will discharge any remaining charge. Again, if your oven has not been operation at all, and you've had it turned off and unplugged you shouldn't have anything to worry about.

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