I HAVE NATIONAL MICROWAVE/CONVECTION OVEN MODEL NN-C781 JF.IT IS NOT TAKING POWER SUPPLY..LOCAL REPAIR SHOP SAYS MAGNETRON IS NOT WORKING...WHERE AND HOW CAN I PROCURE THIS SPARE PART?

hi,

sounds like the control board. a bad solder. they cost 350.00 so your best bet is to try and disassemble and look for the bad solder joint on the control board, you could possibly take it to your local tv repair shop. here a link to the part. theres two boards one is power supply noise filter and logic. inspect both, make sure you stay clear of the HV red power lines running to capacitor magnetron, use a screwdriver and discharge the capacitor to frame before you start

jm



Sharp R980A R980A CONTROL CPWBFA753WRK0 Microwave Not Heating

Microwave Not Heating

Judging from the model and without looking it up I expect that unit has an inverter. If it is not the Switches and you have replaced the mag, the inverter is the power supply for the mag to work so either mag not getting power from inverter or inverter not getting signals from main PCB Timer board.

A thermal cutout on many ovens is black with two terminals. It's usually held in place by a bracket and one or two screws. Many ovens now use a thermistor instead of a cutout on the magnetron.

Based on the symptoms you describe, it seems unlikely either would be the cause of the problem. If a microwave is run empty, the magnetron will draw excessive current. The excessive current can take out the magnetron, high voltage rectifier, high voltage capacitor, fuse, or a few other components. If this is an inverter oven, check for a fault code of "H98" or something similar. That would indicate a problem with the inverter board, or something else in the high voltage circuit.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

I would suggest that contact the dealer from whom you purchased the oven or call any number listed on the model tag of the oven.

i think you have a problem with your magnetron or the inverterpcb if your unit has inverter inside writen on the front it could be an expensive repair please contact me to let me know iffell up to tackling this repair as it can be dangerous

Http://www.retrevo.com/samples/Microwave-manuals.html

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 on high resistance range for short circuit, the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.

Check High voltage rectifier diode if it is ok replace the Magnetron.

Does this unit have a turntable? If so does it turn when on?

In most cases, this is a problem with the inverter or a bad magnetron.

Due to the lethal voltages used and produced, I do not recommend that an inexperienced person work on these.

I would recommend that you contact your nearest Panasonic-authorized servicer. You can find one here.

We're happy to help and we appreciate your thoughtful rating of our answer.