790.48133800 Kenmore Elite double oven loses controls and shuts off after “a while”

[rich.theil]

Model Number

790.48133800

Brand

Sears Kenmore

Age

More than 10 years

Hi,
I’ve got a Kenmore Elite double oven (790.48133800) that runs normally until it randomly decides to shut itself off - usually after running for about 20 or 30 minutes (it varies and seems to take a little time before it shuts off). Notably, it does not trip the breaker and it will not work again until some time has passed (even if I manually flip the breaker off and back on as a “hard reset”).

I’ve taken the oven out of the wall to examine it.

I’ve examined the two control boards and I don’t see any popped capacitors or burn marks. I checked both sides of one board, but only the top of the relay board (it’s more challenging to remove).

I’ve also removed the back panels from the oven and found one small burn mark - about the size of a penny (see image of sheet metal). The burn mark corresponds to the wires for the upper oven’s top heating element.

I suspect the burn mark came about because the heating element wire made contact with the sheet metal. I think this happened because over the last 10+ years, we’ve used that upper oven quite a bit and I think the heating element wire coming into contact with the sheet metal is causing a short and shutting down the electronics.

The other two photos show the difference in the angle of the connection between the upper heating element for the top oven and the upper heating element for the bottom oven.

I bent the wires down for the top oven as a way to eliminate this particular problem.

My questions

• Has anyone seen this before?
• Is it likely the cause or do you think I have something else going on. Notably, there is one thing that casts doubt on this being the likely cause…we have this problem whether we are using the top oven or the bottom oven. I would think it would only happen if the top oven were in use.
• Thoughts on what it could be?

Thanks for your help.

Rich

 

[rich.theil]

Update…that didn’t fix it. We just ran the oven for about 40 minutes before it randomly shut off…What do you think I should try next?

 

[Dan O.]

decides to shut itself off

What exactly do you mean by that? The control goes blank or it just stops heating? Both ovens for just one?

I suspect the burn mark came about because the heating element wire made contact with the sheet metal. I think this happened because over the last 10+ years, we’ve used that upper oven quite a bit

I very much doubt it was just use that caused it. Has it ever been serviced previously?

think the heating element wire coming into contact with the sheet metal is causing a short

That is quite possible but as I said, not from normal use.


Dan O.

 

[rich.theil]

Thanks for the reply, Dan. I'll comment back on your questions below

What exactly do you mean by that? The control goes blank or it just stops heating? Both ovens for just one?

When it shuts itself off, the entire control stops working (goes blank and the buttons don't work) and the oven turns itself off (stops heating). When it happens, it happens to both ovens at the same time. It's as though someone flipped the breaker. The breaker hasn't actually flipped, but that's what it's acting like.

I very much doubt it was just use that caused it. Has it ever been serviced previously?

The only time it's been serviced is by me – I replaced the board with all of the relays on it ~6-7 years ago. At that time, I didn't open the back of the oven (where the burn mark is). I only opened the top, to get to the control boards. The back of the oven hasn't been opened since it was manufactured (though I suppose the bottom part had to be opened to connect the wires to the wiring block). I also installed the oven, so I don't think it was the installer .

That is quite possible but as I said, not from normal use.

Not sure what you mean and I agree that it's odd. Unfortunately though, it's only ever been serviced by me and yesterday was the first time it's been completely out of the cabinet in 10+ years. It's been highly reliable – only the one time with an issue (which I fixed by replacing the relay board). We are a family of 5 and we cook a lot – especially with the upper oven. Perhaps it was a manufacturing flaw and it really didn't cause any major issues, so for this problem, it's a bit of a misleading clue (since that doesn't seem to be the root cause of the issue anyway). I'm perplexed .

Thoughts? Perhaps it's the relay board again?

Appreciate the help.

Rich

 

[Dan O.]

I didn't open the back of the oven (where the burn mark is). I only opened the top, to get to the control boards.

Than I can not explain the burn. I can't see it happening just from normal use. Maybe expansion of the metal the oven cavity is made from as it heated (often referred to as 'oil canning') but I've never heard of such a case. Maybe a shelf or pan jammed against the rear of the range when the door was closed?

Bending the element terminals might solve it if not bent too much to damage the insulation at the tips of the element. That insulation can be brittle and fracture and flake when the terminals are bent too much.

When it shuts itself off, the entire control stops working (goes blank and the buttons don't work)

That might be more likely due to the relay board failure but any interruption in the power supply to the relay could be responsible. That could be just one leg of the power supply dropping out due to a loose connection in the wall outlet, at the main terminal block of the oven or the wiring anywhere from there to the relay board. That is going to be difficult to isolate unless it happens during testing with the appliance out of its enclosure so those components can be accessed at that exact time. I don't see any safety thermostats that could be responsible.

Inspect and tighten all connections in the wall outlet and at the main terminal block while also observing for discoloration. If that isn't it, someone might need to check for full 240V power at the main connections to the relay board. If both legs are present, I might suggest the relay board might be the culprit.

LINK > Kenmore 790.48133800 Relay Board # 316443910



Dan O.

 

[rich.theil]

Than I can not explain the burn. I can't see it happening just from normal use. Maybe expansion of the metal the oven cavity is made from as it heated (often referred to as 'oil canning') but I've never heard of such a case. Maybe a shelf or pan jammed against the rear of the range when the door was closed?

Bending the element terminals might solve it if not bent too much to damage the insulation at the tips of the element. That insulation can be brittle and fracture and flake when the terminals are bent too much.

Yes, strange. Hopefully the bending helps. Thanks.

Inspect and tighten all connections in the wall outlet and at the main terminal block while also observing for discoloration. If that isn't it, someone might need to check for full 240V power at the main connections to the relay board. If both legs are present, I might suggest the relay board might be the culprit.

Will do…won’t be for another week or so give my schedule. I knew I was gonna regret not opening that wall box

Thanks for all the help. I’ll post back after taking a look inside that box.

Rich

 

[Broken-Oven]

Interesting, I am having a similar problem with my Kenmore double oven, model 790.48183000, built September 2011. While the unit is cooking, it will go dark and reset. It has happened 8 or 10 times in the last 4 months, and it has happened while using the upper oven only, the lower oven only, and when using both. Sometimes there is a popping sound. Other times we have heard the alarm tone give a short beep. The ovens will turn off, the oven lights will turn off, and all is dark except the clock displays 12:00. It is as if someone pressed a “reset button”.

The unit can be immediately started again (unlike the description in this post where it takes “some time” before the unit will work again), and as in this post, the circuit breaker does NOT trip. Your suggestion to inspect and tighten all the connections in the wall outlet and terminal block sounds interesting. Any other ideas would be welcome.