Whirlpool Oven Control Board Fault

[trout007]

I have a Whirlpool Oven and recently when I go to bake mode the broiler element comes on and stays on. It should typically cycle on and off to help the preheat time. When I shut off bake mode the element goes off. I checked the resistance of all of the heating elements and they are in spec. I checked the sensor and it is working fine. I checked the relays with the oven unplugged and all of the outputs are open. Is it possible the output relay to the broiler is stuck on only when powered? Is it worth trying to replace the relay for $8 when a new control board is $300?

https://postimg.cc/B8Tb5DRZ
https://postimg.cc/D8jQVVjk

 

[Tha fios agaibh]

Is it possible the output relay to the broiler is stuck on only when powered?

Not likely. Relay contacts could stick on, but usually stay stuck.
Might be a problem with a nearby circuit that drives the relay. Perhaps a shorted component?
You could solder small wires on the relay coil so you can monitor its signal remotely if necessary.

 

[PETERDECO]

Before you buy a new board for $300 from a parts supply, check out ebay. I've bought microwave oven parts for $7 compared to $75 from parts supply.

 

[Bluejets]

Must be a lot of them around given the number that fail in here.

 

[narkeleptk]

I do not really know much about ovens but should this thermo fuse be opening once preheating is not needed any longer? If so maybe its not doing it.

 

[trout007]

Before you buy a new board for $300 from a parts supply, check out ebay. I've bought microwave oven parts for $7 compared to $75 from parts supply.

I've looked and haven't found any that cheap. Mostly refurb services that charge $150 but can take a week or so. I'll try replacing the relay and report back

 

[trout007]

I do not really know much about ovens but should this thermo fuse be opening once preheating is not needed any longer? If so maybe its not doing it.
View attachment 46785

I think that is more of an safety fuse if the sensor fails. It checked out a closed connection

 

[trout007]

I did some testing with a multimeter and found whenever the oven is in bake mode there is always at least 115V across the broiler element on the schematic between red/white and blue. In some modes it cycles between 115V and 240V. Any ideas why there would always be 115V? Sounds like an issue with grounding one side?

 

[trout007]

OK. I think I fixed it. I forgot about 240 logic. I was measuring to red/white and it was 115 because when the relay is de-energized it must have a way to bleed to neutral or ground. I was measuring the K1 relay turning on and off. I ended up replacing the relay and it seems to work perfectly now.