Amana RSBG459P light on panel dead

[jpe]

Model Number

RSBG459P

Brand

Amana

Age

More than 10 years

Hello. I have an old Amana, standard model number RSBG459P manufacturer model number P1110412M, microwave that has been working ok. Recently, sometimes, the oven light would come on when loading the oven, but pressing the control panel wouldn't result in digits displaying on the lcd. The panel wouldn't light up unless the door was opened and closed a few times, or we could just leave it, come back later, and it would work. I think the digits on the lcd may have even started flickering some. Not randomly flicker. For example, if a 3 was pressed, it would fade in and out.

Currently, the panel is dead, but the oven light still comes on when the door is opened.
I'm thinking it's either the door switch or the control panel. Can somebody help me figure out how to tell if the control panel is getting power? I've attached the wiring diagram.

Thanks.

 

[Wx4usa]

Sounds like two issues. The door interlock switches will cause the intermittent interior cavity light. The fading digits is likely a failed control board. The control board and user interface is showing no longer available.

 

[jpe]

Sounds like two issues. The door interlock switches will cause the intermittent interior cavity light. The fading digits is likely a failed control board. The control board and user interface is showing no longer available.

Hey. Thanks for your reply. I should've been a little clearer. The oven light isn't intermittent. I was just pointing out that the light was on - meaning the oven had power.

I agree with your assessment regarding the control board. I noticed the old board has a leaking component - maybe a diode? Also, posting on the forum forced me to do some due diligence and study the wiring diagram again. I believe the low voltage circuit is an AC circuit and is pretty simple. There should be power at the control board always. It's not dependent on the door switch like I thought. Since the oven light is on, I can conclude the main fuse and both thermal cut off switches are ok. That lead me to check the voltage at the plug control board, the yellow and white wires, and sure enough, there's voltage there. So, it's almost definitely the board.

I've got a new board on the way. Hopefully that fixes it.

I've been thinking about changing the magnetron due to it's age, and the heating performance of the oven isn't what I think it should be. It's a 1500W oven, but it doesn't heat quite as well as the, like 7 or 800, el cheapo we're using as a temporary replacement. Will ohm tests on the capacitor, transformer, and magnetron tell me if the components are wearing out, or is it reasonable to just replace the magnetron due to it's age?

 

[Wx4usa]

It is difficult to test a range of performance. A diode is pass fail. Magnetron is pretty much the same… pass fail… without sophisticated test equipment. Capacitors will fail out of range occasionally. Plus or minus 5% is usually ok. if you want to replace, I’d go with the manufacturer’s direct replacement magnetron, cap and diode. You get in to issues when you change them to a different part number without redesigning the circuit.