[sp16673]

Unit not heating at all. Everything seems to be working except the heating function. Unusual buzz when magnetron cycles on, but no light dimming during the cycle. Wife says the turntable also seems slower but this might just be a mistaken perception.

[Simon / APP Team]

Hi.

Please, check the magnetron first. Unplug the microwave, discharge the capacitor and check the continuity across the magnetron's contacts and then to the ground. If it's not grounded, then the problem is bad diod.
They are #579 and#597 on the diagram.

Here are the breakdown diagram and Microwave Body parts for GE JTP86BF4BB - AppliancePartsPros.com

Post the results.

Simon.

[sp16673]

Please describe the process to check continuity across the magnetron contacts.
Do you mean resistance? If so, what are you looking for?
When you say "check continuity to ground", what specifically must I do with a VOM and the magnetron and a ground point and what am I looking for?

[Simon / APP Team]

Hi.

Checking the continuity is the same as checking the resistance in this case because we are not looking for any specific number - just continuity.
Don't forget to remove both wires from the contacts.
To check if the magnetron coil is "grounded" touch one of the contacts with VOM's probe and with another one touch the magnetron's body.
If it reads infinity - it's not grounded; continuity - bad magnetron.

Simon.

[sp16673]

Thanks Simon. Since the unit is 8 years old, we decided to buy a new Whirlpool unit which I was able to get this weekend at 35% off. I very much appreciate the expert advice and learned a lot about microwave repair.

[Simon / APP Team]

You are welcome.

Simon.