Repair for Emerson MW8102SS microwave

What probably happened when the power went out is that you had a power surge or SPIKE as well, either before or after power was lost and then restored.

This sometimes can happen just before the power trips at your substation that feeds your house, or else it can happen when the power comes back on.

There are safeguards that are suppose to be in place to prevent this from happening, but sometimes they fail as well.

If you are in a bad area that has frequent power outages I would suggest adding an appliance surge suppressor to your microwave - similar to those like they use on refrigerators.

If your microwave is a 110VAC unit and somehow 220VAC is crossed circuit wise (as in underground, etc) then the same thing can cause your present day problem as well. Happened to my neighbor once and the same thing happened to their Litton Microwave. They gave it to me free, as they were just going to throw it out anyway.

I was able to open it up and get the part # off the L.V. XMFR and ordered a new one for like $10 direct from the XFMR mfr after getting their factory phone #. Litton wanted $36 for their same identical part. $$$

When this power outage happens like it did to you then you get a surge of current that will overload the primary side of the LOW VOLTAGE Transformer (XMFR) and causes it to go open circuit in the secondary - as in - it makes a break inside the XFMR itself causing the Control Panel to go dead as well. Because this AC XFMR is a step down type that takes 110VAC and drops it down to say maybe 18-24VAC you can see why it wouldn't like 220VAC on the primary side - as then the secondary side would rise up to say 36-48VAC which is way too high for the DC rectified voltages that run the Control Panel logic circuits, etc.

Nothing will work at this point except maybe for the cooking chamber light - maybe? If the Low Voltage XFMR has a fuse in it's circuit that fuse can be blown. If there is no fuse for that circuit then the L.V. XFMR has to be replaced. Usually the XFMR part will cost anywhere from $18 to maybe $35 if you can get one.

If you know someone that is handy with a DVM (digital volt meter) perhaps they can OHM out the primary and secondary side of that L.V. XFMR for you as I firmly believe that is your only problem.

One thing you might check first though is if there is a Circuit Breaker (CB) on the back of the MW unit. If it has one chances are it may have tripped, and by pushing the popped button back in - your problem would be solved hopefully. IF it even has a CB.

Hope the info helps out?

Best regards,

Frank