The (B) button is faulty, either need to change due to faulty spring, also might need a new circuit board. The (B) button is sticking, does not switch off. Please advice. Thank you.

You probably either have a bad connection between the touch pad and the main circuit board, or a component failure on the main circuit board.

Whenever I come across something like this, I always check the door switches for proper operation. Some ovens will not program if they have a switch failure.

Unless it's a door switch, or something else that's inexpensive to fix, I would suggest buying a new oven. 17 years old is quite old. Even if not used much, some components will fail simply due to age.

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

Good day: The door switch is not contacting properly due to the lever that contacts the switch being loose(probably a screw that was not tightened properly during assembly at the factory, or even the screw that secures the switch unit itself might be loose causing play, that is why when you pull at the door it works. Just take it to an ordinary appliance repair shop and they should be able to fix it without too much effort and retain your receipt and present it to the agents challenging them on their failure to provide service when they should have, thereby forcing you to seek other assistance as a last resort, and hopefully they will not void the initial warranty that normally comes with a new appliance. (Warranty states that no one other than the agents are allowed to repair the machine during the warranty period).
Good luck.

Possible that the display unit or the main processor unit is faulty; It is possible that insects could have nested within and produced accumulation of dirt within the circuits to dampen and short the circuit. Remove front panel and clean , use dryer to warm. If the fault persists it can be due to faulty or weak LCD.

Possible that the main program controller unit is not shutting down due to the relay being latched ON even after the time is finished.
You need to check if the processor cuts off the relay and still if the relay holds down, If so the relay drive transistor or the relay is faulty.
Also it can be fault of the program processor/timer as it fails to cut off the relay drive. If so check the circuit, wash the board if you find insects secretion. Also try to solder the processor and associated circuits and try again before the board is confirmed as a suspect.
take estimate and decide.

Faulty Magnetron or Power supply for it.

DO NOT try to REPAIR this Inverter Power Supply (U) and also DO NOT RE-ADJUST PRESET VOLUME on the board. It is very dangerous to repair or adjust without sufficient test equipment because this circuit handles very high voltage and very large current. Off alignment or inverter board operation is dangerous. Operating a misaligned inverter circuit is dangerous due to the very high voltage and current that is produced by this board. Defective boards must be replaced with a new one.
Consult an approved Panasonic Microwave Repair Service.

You have a faulty keypad. You could probably special order this part from a local appliance parts supply store for 50-60$ or purchase a new microwave.

That fault is a little tricky. Need to check if you are getting voltage onto primary of transformer. If you are, the problem is almost certainly the magnatron which has gone open circuit. If and when you replace it, change the cap and HVdiode. Wont be sorry if you do. If no voltage there , your board is faulty. replace it.

Hi cschnur,
     It seems that you might need to replace circuit board.
All the above mentioned conditions refers to a faulty circuit board. You might have blown few Ic's.
Take a voltmeter, check the continuity. If you are aware of the Ic's, replace them.
Unless, look for a tech, a used board ( On http;//www.ebay.com ) or purchase a new one.

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This is usually due to a grease buildup on the sides of the door open button or the frame that holds it.

It may also be a weak door button spring.

You'll need to remove the cover to see how the door open button works.

You can order parts here.

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