Question about LG LMV1650ST Microwave Oven

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DEAD I was given this LMV 1650 microwave by a friend to see if I could repair it. The unit was manufactured only two years ago; apparently, one morning he came down to use it and it was dead: no clock, no lights, no anything. I dissassembled it just to see if the line fuse was blown, and replaced it for good measure. Dead. Still Dead. Any suggestions what to check for next? Also, I have read that I should discharge the capacitor; is their a recommended way to do this? with the way the leads are insulated, I can't really get a screw driver across both and touch the edge of the case. Thanks. Robert

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  • treo23611 Jan 30, 2008

    I found the problem. The fuse was fine; however, there are two thermal relays / thermostats that are in the circuit, one at the magnetron and one in the oven cavity. The oven cavity thermal relay had no continuity across it. Once I replaced it, the unit appears to be working fine for now.

  • treo23611 Jan 30, 2008

    I found the problem. The fuse was the first thing I checked; there was continuity across it indicating that was not the problem. It was then suggested to me to check the two thermal relays/ thermostats in the oven to make sure that both had continuity across them. Apparently, these thermal relays are in the main power circuit and if blown prevent power from going to the unit.

    Sure enough, the oven cavity thermostat was open. Upon replacement, the oven appears to be functioning fine.

    I had some difficulty locating the part number for the LG. I came across an LG customer service site that is not posted, but has service manuals for LG appliances:

    The site has exploded parts diagrams, service manuals, owners manuals, and parts lists.



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Make sure unit is not plugged in. Use a Volt-Ohm Meter, on Ohms setting, and see if you have connection to the fuse holder. Put one meter lead on the BLACK ac wire, test the ac plug with the other lead (both sides) One should read. Do the same with the WHITE ac wire. One should read.If you get readings on both sides then AC Cord is good. Next check the fuse holder for signs of heat or dis-coloration. If found replace fuse holder. Always remember just because a fuse looks good does not mean it is good, and also I have replaced a fuse with a NEW bad fuse. It happens. To be sure test with meter.

Posted on Jan 25, 2008


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