Not working microwave cut off and has no power

You cannot repair this yourself, replace it. google Panasonic nn-cf7788s error code h98 for more info.

Door Switch Start Your Repair Here
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- Takes less than 15 mins
We have 13 installation instructionsThere are many reasons your microwave won't turn on, one of which might be a faulty door switch. The door switch, also known as an interlock switch, signals other microwave components to begin powering when the door is closed, and to stop when the door opens. For this reason, everything else may appear in working order but the microwave will not begin heating. To access the door switch or interlock switch, unplug the microwave and dismantle the cabinet. The switches have terminals which are marked C for common and NO for normally open. Check each terminal with a multi-meter for continuity. If there is continuity while the actuator button is engaged, that means the switch is working. If there is no continuity, replace the switch. You can also take this opportunity to make sure the door hooks are working properly.
Ceramic Fuse Start Your Repair Here
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- Takes less than 15 mins
We have 1 installation instructionIf your microwave won't start and the display is blank and unresponsive, the issue may be with the ceramic fuse. This part protects other microwave components from power fluctuations, and causes a complete loss of power when it fails, meaning your microwave won't work. To access the ceramic fuse, located inside the cabinet near the power cord, first unplug your microwave. Use a multi-meter to test the continuity of the fuse. If you are aware of the cause of the fuse failure, such as opening or closing the microwave door, you can also test the door switch to see if that is working. If you are unaware of the reason for the fuse failure, you may want to test other microwave parts such as the magnetron, high voltage diode, capacitor, and transformer.
Thermal Fuse or Cut Out Start Your Repair Here
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- Takes less than 15 minsA problem with the thermal fuse or cut out could be the reason your microwave won't turn on. The thermal cut-outs, also known as thermal fuses, help keep the oven from overheating. When the thermal cut-outs fail, your microwave won't turn on as a safety precaution to keep it from getting too hot. To access the thermal cut-outs, first unplug your microwave and then remove the cabinet. Once you locate the thermal fuse, disconnect its wires from the terminals. Use a multi-meter to test for continuity, and replace the thermal cut-outs if there is no continuity. Take this opportunity to also check that the cooling fan is working and not causing the microwave to overheat by cutting off airflow.
Door Latch Assembly Start Your Repair Here
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We have 4 installation instructionsYour microwave may not start because of an issue with the door latch assembly. Most door latch assemblies are made of plastic hooks that stick out of the door and engage the door switch when the door is closed, signalling the rest of the controls to power the microwave. If the hooks are damaged or lacking tension due to worn-out springs, the switch will not latch properly meaning the microwave won't turn on. To access the door latch, first disconnect the microwave from its power source, and remove the inside door panel, which is held in place with plastic tangs. Inspect the door latch and replace it if it appears to be damaged.

All microwaves has both internal thermal cut out and internal fuse, Yours problem sounds like an open 9 volts transformer that power up the front panel

Hello

Plug the microwave into the outlet if the microwave won't power up. Make sure the plugs on the microwave match the type of outlet. A four-pronged outlet can only be used with a four-pronged plug. Same with three-pronged outlets---they only work with three-pronged plugs.


Inspect the plug. Make sure it hasn't been cut or tampered with. Four-pronged plugs can't be cut down to fit a three-pronged outlet. Three-pronged plugs mustn't be forced into four-pronged outlets. A three-pronged plug mustn't be used in a two-pronged outlet, either.


Replace blown fuses, or if there's a circuit breaker, check it for tripped breakers. Sometimes the trip won't be obvious, so cycle the circuit breakers. Turn them all the way off and then back on again.


Plug another appliance in the outlet. You will find this easier with three-pronged appliances. Simply plug a toaster, or other appliance into the microwave's outlet, and see if it works. If it works, you know the problem is with the microwave, not the power circuit. Have the microwave serviced or replace it. If the toaster or other appliance doesn't turn on, you know the problem is with the circuit.

1) Plug the microwave into the outlet if the microwave won't power up. Make sure the plugs on the microwave match the type of outlet. A four-pronged outlet can only be used with a four-pronged plug. Same with three-pronged outlets---they only work with three-pronged plugs.
2) Inspect the plug. Make sure it hasn't been cut or tampered with. Four-pronged plugs can't be cut down to fit a three-pronged outlet. Three-pronged plugs mustn't be forced into four-pronged outlets. A three-pronged plug mustn't be used in a two-pronged outlet, either.
3) Replace blown fuses, or if there's a circuit breaker, check it for tripped breakers. Sometimes the trip won't be obvious, so cycle the circuit breakers. Turn them all the way off and then back on again.
4) Plug another appliance in the outlet. You will find this easier with three-pronged appliances. Simply plug a toaster, or other appliance into the microwave's outlet, and see if it works. If it works, you know the problem is with the microwave, not the power circuit. Have the microwave serviced or replace it. If the toaster or other appliance doesn't turn on, you know the problem is with the circuit.

This is happening due to either the magnetron, or the Power Diode, or both, is breaking down, under load, then the unit detects the fault condition, & then, for safety reasons, to avoid a fire or explosion, shuts down the system. You need to take it in to be looked at please obtain a "Quote" before proceeding with any work. This way you can decide to repair or replace.

Hi,
Here is a tip that will help you to figure out what is wrong with your Microwave Oven....

Microwave Oven Basic Troubleshooting Tips
http://www.fixya.com/support/r5508031-microwave_oven_basic_troubleshooting

heatman101

I had that issue and I opened the unit and there was a fuse near where the power went in. Went to the small local hardware store and they ordered it. It was well under $5 (can't remember) but it still works over 10 years later.
If the fuse blew again I would have trashed the unit.

You most likely a shorted capacitor which is causing the fuse to blow. This is part of the microwave HV system and isn't in use during convection cycles.

the unit may be detecting a mal-functioning magnetron.