Maker Pro
Maker Pro

Electronic Repair question

I have a Panasonic microwave NN-S950WA which belongs to my parents. It will start but stops in few seconds (10 to 15 secs.) Clock and functions are working fine. During a lightning strike it hit entire house that killed their microwave, TV, cordless phones, etc. I tried to trouble shoot microwave. The fuse is OK. I believe it is Low Voltage Transformer which is located on a circuit board that is behind touch pad board. Transformer is reading 200-300 ohms which is OK. But there is a varistor to protect circuit in high power surges. I checked this varistor and it seems like bad. I removed it and microwave still does the same. Do you think I have to replace the varistor for microwave to perform if everything else is OK? I learned that it can run without varistor as it's function is to only absorb high voltage spikes during abnormal cases. Please help and let me know if I need to check anything else.
 
yap it got creamed allright. the absorb are there on purpose you may remove it and see if it works ok now. but i would never disable it. replace it or add into your line protection expecialy since what you have prescribe is occuring..
 
So if the appliance is not runnnig normal after removing the varistor, something else is wrong? Find the problem part, replace and reinstall new varistor for future protection?
 
I found it let me explain what happen when the liGhting strike millions of ampers curreNt raise the whole house some XXX voltage so the 120v is higher by x volts. microwaves are devices that extensivly use CMOS chips and controllers the absorb did its job and died it was neve neant to protect a lighting strike just normal 120v up voltage. Cmos are highly sensitive devices even conbing your air and touchin them can and will cause damage. i tell you should buy a new one messing with microwave can cause some damage to you cats and dogs if they leak/ and you will never know. $40 and you are cooking again. i will not pesonaly fix such and item cheper better is REPLACEMENT.
 
The MOV is not the problem.
Normally a MOV is a high resistance, near infinity since it decreases rapidly when the design voltage is reached in an attempt to short the excessive spike. If it was bad it would be shorted or damaged so it fails to clamp the next spike. If you sort out the real problem then replace it. Otherwise don't.
Len
 
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