Came to me with a blown fuse. Disconnected power, checked HV capacitor was discharged, and began troubleshooting.

- Tested the 3 door switches and power relay connected to PCB. Switches tested correctly with door open and closed, multiple times.

- Checked door latch alignment. Nothing loose or out of alignment.

- Checked for signs of loose connections, wiring issues, burns or signs of overheating. Everything looks good.

- Checked all other major components for possible issues, shorts. Nothing found.

Replaced fuse, button-up cabinet, connect to power, open and close door multiple times, place a cup of water inside cabinet, run for 30 seconds (do this multiple times switching out cups of water) and it works.

Return microwave to owner, owner uses for one evening several times, no issues. Tries to use in morning - dead. Assumption is that last operation of microwave in evening blew fuse without owner noticing.

Pick up microwave, find blown fuse, test switches again. Switches test proper. No visible signs of excessive heat or problems, no components test failed or shorted. Close up microwave, connect to power, run for 30 seconds with cup of water inside, open door, close door, run for 30 seconds again, open door, close door - FUSE BLOWS.

Has to be a door switch - test all switches, again. This time I use an analog meter to see in real time when switch opens and closes. ALL switches work without delay. Power relay contacts are in OPEN position, as they should be.

3 mechanical switches and one electrical relay involved with the door function:

- Primary interlock switch

- Secondary interlock switch

- Monitor switch

- Power relay on main PCB

​I am at the point now where I am assuming that the circuit board is intermittently glitching causing the power relay contacts to CLOSE when the door is closing. This would cause a direct short and blow the fuse (I tested this by disconnecting the power, disconnecting the leads form the power relay, putting a jumper across the leads to simulate CLOSED contacts of power relay, and then closing the door with a meter connected between L1 and N - meter goes to 0 ohms/dead short). But I can't prove it under power which is why I am hesitant to just throw parts at it to attempt a fix.

3 switches = $60.79 CDN before tax and shipping

PCB = $128 CDN, out of stock

Parts found here:

https://www.partstown.ca/panasonic/ne-10...

I could risk $60.79 on switches that appear to be working just fine or $128 on a PCB ( if I can actually get one) that I can't guarantee is the source of the problem. No smoking gun and no desire to waste money.

Any suggestions for troubleshooting this issue further? Thank-you

⟐ Commented December 13, 2025 at 14:44 MST

Hello all,

I’m working on a GE microwave, model JVM3160DF5WW.

Background:

•             I recently replaced both the primary interlock switch (WB24X10047) and the secondary interlock switch (WB24X829) because the unit required slamming the door to start a cook cycle. That issue is now resolved.

New Symptom:

•.   Slamming the door (to which we have become habituated) sometimes causes the fan to start when no cook time has been set.   Opening and gently closing the door turns off the fan.

The display does not start a countdown; only the fan runs.

Question:

Has anyone seen this specific symptom? Would you recommend testing/replacing the monitor switch?

Thanks in advance for your help!

Ron C.

⟐ Answer edited December 12, 2025 at 23:14 MST

The old switches were Starion SZM-V16 and the Omrons are V-15-2C26-K

⟐ Commented December 09, 2025 at 18:56 MST

⟐ Answered December 09, 2025 at 18:50 MST

⟐ Answer edited January 26, 2026 at 9:19 MST

⟐ Commented November 29, 2025 at 10:32 MST

⟐ Answer edited November 26, 2025 at 18:33 MST

⟐ Edited November 26, 2025 at 2:09 MST

⟐ Answered November 23, 2025 at 8:00 MST

⟐ Commented November 21, 2025 at 23:13 MST

⟐ Answered November 21, 2025 at 23:10 MST

⟐ Answered November 16, 2025 at 11:10 MST

Any help is appreciated.

Thanks,

Brett

⟐ Commented November 15, 2025 at 20:14 MST

⟐ Commented November 09, 2025 at 22:32 MST

This time, fuse blew again so I took it apart. The three door switches all test okay: clicking correctly and continuity test check out whether normally open or normally closed. Replaced the 20a fuse again, but when plugged back in there's no power to the control panel. Fuse is good and there's continuity across the fuse to the other contact.

The two thermal cut offs directly behind the control panel test ok, but I haven't been able to reach the "Cavity Thermostat Cutout" for testing. The unit shouldn't have reached anywhere near the 230F temperature listed to blow that, but I guess it's still possible this has failed.

Other possibilities? I see a H.V. Trans Fuse listed and it could possibly be a bad Magnetron. These or possibly a new control board?

I'm reaching the limit of my abilities as a non-licensed/weekend hack/cheapskate just trying to keep a microwave running. Time to just spring for a new one and play the "disposable appliance" game?

Thanks for any insight

Was trying to put a picture up too

⟐ Commented November 06, 2025 at 3:35 MST

⟐ Commented October 28, 2025 at 13:33 MST

it maybe worth mentioning that, the original cause was a bad door switch that was replaced and seemed to work fine afterwards, however now I've learned that after a few hours of no use (like over night), it trips when opening the door again. Once every morning, very frustrating.

I can't find any discoloration on the boards

Thanks for any help

⟐ Edited by author October 15, 2025 at 22:56 MST

⟐ Commented September 24, 2025 at 13:57 MST