Microwave cut off

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Panasonic NN ST652W Manuals

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.

Hello Two options to try: a) Press the Clock / Timer button 3 times b) Unplug, wait a few seconds, then re-plug to power up with the factory settings. You will need to reset your clock and any favourite settings.
This should work with all Panasonic Microwave models.
Good luck

hardware store..

My panasonic microwave model # NN-S540BFW stops after 4 seconds after you hit the start button and cuts off on its own. What is wrong with my microwave?

If it stops after 22 seconds, that means the controller has detected a problem, usually 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.

You can find an authorized Panasonic servicer here.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Maybe bad fuse or fuse holder or both

This model uses an inverter to produce high voltage instead of a convential transformer system. While an inverter (switched-mode power supply) is more efficient from a power consumption standpoint, it is more complex, thus more statistically prone to fail. These should only be examined and worked on by someone who has the necessary technical qualifications. Seriously. Often the machine-soldered connections in a microwave inverter are too weak, so they eventually fail, especially if heat is high in the area. They sometimes fail catastrophically. When not catastrophically damaged, you may hear clicking or squealing and may smell an electrical odor, which is sometimes obscured by the cooling fan. Some manufacturers do not encourage or assist technicians to repair microwave inverters. Most offer the inverter as a whole assembly. But sometimes that is actually cheaper than the time and labor required to fix the old one. If a technician is willing and able to troubleshoot and repair the inverter to component level, it will may be expensive, but may be worth it, especially if he or she will resolder and reinforce connections as needed as part of a thorough repair. That could easily make your inverter beter than a new one! You might be able to get some verbal estimates if you call Panasonic-authorized repair shops and ask then specifically about inverter repair and inverter replacement costs for your model number.