My microwave was performing correctly except for “no heat.” I troubleshot the problem to a thermostat (#115 on this website’s interior diagram). After installing the new part, the microwave no longer has a display. I do have the 110 voltage. The original part had 150/0 on the underside. The new part says 40/56. This was a genuine renewal part from GE and am not sure if it is a correct replacement. Anyone experience this?
Hi.
This is the part you need AP4344046
Check the 20amp fuse, magnetron and cavity thermostats.
Jump the thermostat in question to check if that is the only problem.
Post the results.
Simon.
Hi Simon and thank you for your response. I was wondering, how did you identify this part? The picture below is from the parts list and item #115 is the part I found to be bad. I don’t mind getting the part you listed but I just didn’t see it in the drawing.
GE WB27X10932 Thermostat - AppliancePartsPros.com
When t-shooting, I found the transformer was not getting the 110vac. When I routed 110v straight to the transformer, the microwave heated up the glass of water. I found the thermostat to be a short. I will go ahead and order the part you mentioned if that is what I SHOULD have ordered instead of what the drawing listed.
Thanks again, Simon.
Hi.
What was the original symptoms?
The reason the transformer isn’t getting 120VAC could be bad door switches in the first place or bad control board or open cavity safety thermostat.Put back the old thermostat and run the tests.
Post the results.
Simon.
The original problem was “no heat.” I checked all the door switches and values were “infinite” with door open and “short” with door closed. I checked the primary and redundant of the transformer and values were correct per the troubleshooting steps.
The diode and HV cap checked good also. I called the 1-877-477-7278 and told the rep which part (per the diagram/drawing) I was looking for. She said the part I received was correct and is an acceptable replacement since the original part is no longer manufactured.
I actually received the part through my local appliance parts store and it is the exact same part number as this website. I had read on a different search that 150/0 was the thermostat range. Not sure why the new part has 40/56.
Hi.
Is the old 150/0 thermostat open? If it is jump it and check if the m/w works.
The part number I posted is identical to the magnetron limit thermostat.
The 40/56 thermostat is normally open and it’s a hood thermostat, not turning off power to the hi-side transformer.
Thank you.
Simon.
Hello Simon. It’s a short.
Hi, Kaiden.
Please be more specific on “It’s a short”.
Did you try to jump the thermostat #110?
Simon.
Hi Simon.
TCO #115 is a short (0.2 ohms). I still jumpered it per your instructions but same status: everything works yet no heat.
TCO #110 reads infinite. When this is jumpered, the fan starts running as soon as I plug in the 110v.
That means that those two thermostats are OK.
Let’s do the t/s again.
When you program the control and start the m/w does the light, turn table and fan turns on, clock is counting down?
Or only clock is counting?
Simon.
Simon,
Wow, thermostats are good. Well, back to the drawing board! :eek:
Ok, when I program the control and start the m/w: light comes on, fan starts blowing, turntable spins and clock counts down.
Hi.
Take off the two leads from the transformer’s PRIMARY winding and check if there is 120VAC between them.
If the correct voltage present and you already checked transformer, diod and capacitor - replace the magnetron.
Simon.
Hi Simon,
Taking measurements at the primary leads to transformer, I do not have 110v. When I hardwire 110v straight to the primary, microwave works.
Hi.
It’s got to be the control board.
Jump the Power relay RY2 (Y/W to Y/R). Make sure the door is closed. Kicks on - replace the board.
Please be very careful. If you don’t fill comfy - remove the wires from the relay, start the m/w and check if there is continuity between the relay contacts.
Good luck.
Simon.
Hello Simon.
So I jumpered RY2 and the m/w came on. Didn’t get to leave it on to check for heat because the connection w/ the jumpers attached was kind of tricky. But it DID come on. Now I get to order a board!
Question: the two thermostats, is one “normally open” and the other “normally closed?” In the schematic that came with the microwave, they are both 150/0 yet one reads short and one reads open.
Thanks for you help btw! I appreciate it!
Hi.
The #110 should be 150/0 - normally closed, the #115 - 40/56 and normally open, but who knows how this thing was assembled. There is another 150/0 attached to the magnetron.
Simon.