[hectorbs]

Runs For 5 Seconds; Then Shuts Off. All Other Functions Seem To Operate (clock, Display, Light, Etc.)

[libertyappl]

Is this an over range microwave?
Nat

[hectorbs]

No. It's A Countertop Model

[libertyappl]

My personal recommendation is that your MW isn't work repairing. You can get one like that at your local department store cheaper than the parts to try to fix that one.
Nat

[MicrowaveDisplaycom]

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.

According to a recent report we received, if it stops after 7 seconds, it has a problem with the inverter.

You said 5 seconds, so I'm not sure which of these may apply, but I would honestly suspect a problem with the inverter.

Due to the lethal voltages used and produced, I do not recommend that an inexperienced person work on these.

I would instead recommend that you contact your nearest Panasonic-authorized servicer.

You can find one here: Panasonic Product Support - Service Locator

But if you or a friend want to swap the inverter, you can order Panasonic parts here: Parts Ordering

I would advise you to see the safety warnings here: all Microwave Display Repair Sharp Dacor GE General Electric

Good luck and be safe.

[hectorbs]

thanks. i think i will take your advice, and scrap it.

[Servicer]

William,
That's very useful information to have. I've seen plenty of Panasonic made Thermador microwave units with this issue. While playing with a working unit, I found that anything I did which caused the mag tube to know not pull amperage, i.e. unhook wires from mag, removing the ground screw from inverter, unplugging cn702, etc., caused the unit to shut down.
I take it there's information that runs from the inverter to the pcb board on CN701. You wouldn't happen to know what readings can be read on that harness, do ya?
Thanks,
KC

[MicrowaveDisplaycom]

Here are some misc tips, some may be model-specific, but should be helpful. NOTE THE PDF LINK AT THE BOTTOM!


Service hints for checking inverter:

- Use ammeter in series with AC cord
- Use container with 1 liter water

---

Some ovens will show fault display

- Program DPC (controller): press CLOCK, TIMER,START, POWER PAD
- Unplug HV lead wire connector CN 703 from inverter
- Program oven for 1 minute and press START
- After approximately 23 seconds oven displays H98 and stops
- Confirm the input current is 0.8 to 1.7 Amps during 23 second operation
- Press RESET pad
- Unplug CN701
- Program oven for 1 minute and press START
- After approx. 3 seconds, oven displays H97 and stops
- Confirm the input current is 0.4 to 0.8 amps during the 3 second operation
- If the above test is satisfied, the inverter can be determined OK

---

Other problems with shut down after 23 seconds:

- c703 - R713 (4.7 ohms 1/4 watt)
- D701 and D702 HV diodes
- T701 transformer ( check if windings are dark- overheated)
- We have run aross this problem with shorted magnetron as well
- Both leads from magnatron (disconnected from inverter) should read infinity to ground.

---

Panasonic used to have a Kit..but discontinued. Need to order parts individually.

Check the large transistor on the Inverter board, (Large Heat sink)next to the Bridge Rectifier. Probably shorted.

BTW...running 20 seconds is correct if the Sense board TZ-1 detects a fault.

Magnetron is probably OK..I believe the Magnetrons on these is Power Input controlled.

---

There is also a file that is model-specific but may be generally useful in troubleshooting inverter-powered ovens, showing waveforms, testing, troubleshooting, etc.

It's at: all Microwave Display Repair Sharp Dacor GE General Electric

###

[Servicer]

Copy, paste, print...

Thanks a lot William - this should really help us out in the field.

KC