20 Most Recent Panasonic NN-S255 Microwave Oven Questions & Answers

Hello,To get the door open and salvage your dinner, take a long thin blade ( I used a frosting spreader) and insert from the bottom between the door and the oven frame on the side with the latches (usually next to the control panel). You may have to pry the bottom of the door open just a bit. The object is to push up the lower door latch (which is connected to the upper door latch) and manually open the door. You may have to try a few times but this worked perfectly for me and saved dinner. Obviously the door latch needs to be repaired but this solves the immediate problem of dinner being held hostage by a recalcitrant microwave.
wish you good luck,
take care.

Hi rttakeda,

Just to isolate the concern kindly do the following and observe if this describes what's happening to your machine:

1. Put in time, push start and unit runs for 2-3 seconds, relay clicks then, unit goes off. Cook time on display goes off and clock time comes back. This means you have bad upper interlock switch and charred connector.

2. Otherwise, if the digital programmer circuit / controller does not get a feedback signal from the inverter for a period of 3 seconds, the controller will stop the cook cycle. This is most likely that you have a loose connection in the wiring between the inverter, magnetron, and/or control board, or maybe one of those components has failed.

I will highly recommend that you contact an authorized Panasonic serviceman. If you are interested you may find here.

Hope this helps.

Thank you for using FixYa.

Hello,

Investigate these three areas if your microwave won't heat

Power Diode

A diode is an electronic component that readily passes current in one direction only and blocks the flow of current in the opposing direction. If your microwave's diode has become defective, your microwave will not heat and you will hear a buzzing noise. Test the diode to determine if this is the cause of your problem. Replace it if it is defective.

Testing a diode

NOTE: Before you test your diode, make sure your microwave is unplugged, and that you discharge the microwave's capacitor.

Whether it is shorted or open, a defective diode will most likely show some sign of defect. Defective diodes will usually emit an electrical burning smell, signifying its defectiveness. Also, it may have split in two, or it may exhibit a burned crack, or possibly even a blistered spot.

A shorted diode is indicated by a loud humming noise from the high voltage transformer, and no heat produced when a cook cycle is initiated. Whereas little or no heat produced in your microwave, with an absence of a humming noise is indicative of an open diode. In either case, the diode has to be replaced.

With your microwave unplugged, and your capacitor discharged, use extreme caution to remove the lead that leads to the capacitor. You can leave the ground connection attached. The side of the diode that goes to the ground is usually marked with a dot, stripe, or arrow. Set your ohmmeter to R x 10,000 or higher. Touch the positive meter probe to the anode and the negative meter probe to the cathode to measure the resistance across the diode terminals. Remember that the cathode is on the side that goes to the ground, which is often marked by a dot, stripe, or an arrow.

A normal diode, that is a non-defective diode, will read anywhere from 50,000 to 200,000 ohms. Differences in microwave make and model account for this large range in resistance readings.

Reverse the meter probes and measure resistance while touching the positive probe to the cathode and the negative probe to the anode. Reversing the probes like this should result in a reading of infinity. Unless a bleeder resistor is present. The presence of a bleeder resistor would produce a reading of the value of the resistor.

High Voltage Capacitor

A capacitor is an electrical device which stores electricity. A defective capacitor may be why your microwave is not heating but you are hearing a buzzing or humming noise. The capacitor will have to be tested to determine if this is the cause of your problem. A defective capacitor will have to be replaced before your microwave will work again. Make sure you discharge the capacitor before you test it, though.

Magnetron

A defective magnetron is the third possible cause of why your microwave is not heating, but you can hear a buzzing noise. Test your microwave's magnetron. Replace it if it is defective.

Testing a magnetron

NOTE: Before you test this component, make sure your microwave is unplugged, and that you have discharged the capacitor.

There are two tests to conduct in order to determine whether or not a magnetron has become defective. If you receive results other than what are detailed below, you will have to replace your microwave's magnetron. Each test is described for you here:

TEST 1: Locate your magnetron and label each of the wires attached to it so that you know which wires are to be replaced where. Set your ohmmeter to the lowest resistance scale. Take a resistance measurement between each of the magnetron's terminals by touching each probe to one terminal each. Reverse the probes and take a second resistance measurement. Each measurement should read less than one ohm.

TEST 2: Set your ohmmeter to its highest resistance scale. Touch one of the meter's probes to a magnetron terminal. Touch the other probe to the metal magnetron housing. Take special caution to not touch the two probes together. This could result in an inaccurate reading. This test should produce a reading of infinity - indicating an open circuit.

Read the tips on the below links on how to replace your microwave oven's diode and how to discharge the capacitor.

http://www.fixya.com/support/r7088355-replace_microwave_ovens_diode

http://www.fixya.com/support/r7088317-discharge_microwave_ovens_capacitor

I hope the above is helpful.

Good luck.

I'm not sure what you mean by "everything works". do you mean that all the lights and the timer work. Could it be in the timer or clock mode? Try pushing the timerand cancel buttons together.
Try changing the time using the clock function.

I believe your model has a child lockout. Please check your manual for instructions on unlocking this function.

Is it hardwired or plugged in? If it is plugged in you can try a power reset, by unplugging it, waiting a few minutes and plugging it back in. It is completely unsafe to try to work on a hardwired Microwave.

Please let us know if this solution is helpful to you. Thank you.