# Kitchen oven problems

Discussion in 'Technical Corner' started by Matthew, Sep 8, 2021.

1. ### MatthewTouchdown! Greaser!

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meh - as long as the smoker still works, and that has 1) no electronics, and 2) no moving parts, and 3) it encourages beer consumption.

I'm good, but we might still need to bake a potato or some dang thing. It's not like I don't have time to shop around, though.

2. ### RushieEn-Route

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When we had a similar problem it turned out to be the control board, which we pulled and sent to the manufacturer to repair, in Canada if I recall. They said they couldn’t and it was outdated and we couldn’t get a new one so we just bought a new oven. We think that it was damaged when our house flooded and short circuited something and caused a power surge. On another occasion a lightning strike fried several things in our home including our big screen TV, the modem and the WiFi. We have since installed a whole house surge protector.

3. ### flyingronTouchdown! Greaser!PoA Supporter

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I lived in the hangar side of my house for nearly two years while building the proper kitchen. No proper oven, but we did have a grill, two smokers, and an Advantium (GE's EZBake oven).

4. ### MatthewTouchdown! Greaser!

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I haven't given up yet, just ran out of time today and probably tomorrow, too.

I looked up the part number of the bake element - it's listed as 3410W. The math I used works out to Resistance = Volts^2/Watts, so R = 240^2/3410 = 16.9 ohms. I measured the element resistance at 16.7 ohms, so that all checks out.

I *might* swap the two elements since I know the upper element does work, but the problem is that I can't easily support the lower element in the upper position. I might not have to go that far, though, if the upper element does heat in the lower position that seems like a pretty good indication the lower element is actually bad even thought it does check out. Every time I pull the element out I end up tearing back the insulating blanket just a little bit, and the assembly process seems to be to attach the elements so they protrude through the insulation on the back wall, then attach the connectors. So when I pull the elements out, there's always the chance the connectors will pull off and I'll have to fish around and try to find the wires. I got lucky the first time, one connection did come off but the other stayed on. I was able to tug on the wire enough to pull it, and its pair, into the interior of the oven for testing. If I end up getting to the point where I HAVE to pull the oven, then I'm probably just going to replace it. It's 25 years old and there's a very good chance that whatever parts are bad are no longer available anyway. We had just hoped to be able to get it limping along a little while longer until we could do our kitchen remodel and replace the wall oven design with a good slide-in range instead.

I'll get around to taking a pic of the wiring diagram when I can get the panel open in a few days. That should also get me a chance to look at the control board and see if there is anything obviously wrong.

I'm still trying to figure out the voltages I was seeing at the element connections. 27V when the element is not heating and 34V when it is. I don't know enough about 240, AC, 120 legs, and phases to make sense of it all.

5. ### asicerFinal ApproachPoA Supporter

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If it's really just for that and you're planning on a full kitchen remodel soon, then as a stopgap...

6. ### MatthewTouchdown! Greaser!

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I started looking at something like that already. I even started looking at some countertop ovens at a restaurant supply store. I'd LIKE something that can handle a turkey and a beef rib roast, but you pretty much need to go full-size for those, although I can always use the smoker.

We need to figure out when, realistically, we'll finally do that remodel. Prices and availability of all kinds of things are still pretty crazy so it might be something we put off long enough that getting a low-end oven until then might be the way we go. Even the current versions of low-end seem to have better/more features that what we have in that 25yo unit.

7. ### MatthewTouchdown! Greaser!

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I might see if I can find a good ground so I can check both sides of the connections going to the heating element. I really don't know where to find that ground, though. I could, if I were to pull the oven out, and that's something I'm trying to avoid. Do you think any unpainted screws into any sheetmetal would work? I'm not sure if I can find anything that's actually a part of the frame. There might be something that shows up when I remove the control panel, I'll look around.

8. ### Albany TomLine Up and WaitPoA Supporter

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Yes. I looked up your meter, and it's listed as having something like a 7 Mohm input impedance. That seems a little weird, they are usually 10 M. Anyway, it's high enough that any bare metal will be fine. You might want to check the meter, though, by checking voltage at the end of a 120v power cord. You can also use an extension cord to get that ground, and to verify your meter. Some Amazon reviews list that meter as reading low. If the meter is accurate, and that stove switches on/off with a relay, is sounds like you have something open on one end, and something at a very high impedance to ground, like 200+Mohms. If it were me, I'd be pulling that thing out of the wall to see what's going on in back. Feels like a bad connection.

Anyway, please be careful with this. 220V/60Hz is just about the perfect setup for the "can't let go" reaction, and to put your heart in fib, as I understand it.

9. ### MatthewTouchdown! Greaser!

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I'm looking at the book right now, it says 7.8 MOhm input impedance on the input.

Your warning is taken, and that's another reason I'm a little hesitant to mess with these kinds of voltages on my own. I've checked the meter on 120V many times, it seems to read pretty well, but I haven't compared it against the Fluke I used at work.

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10. ### Albany TomLine Up and WaitPoA Supporter

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Some of those are pretty nice. We have one that has convection and will bake at up to 450F. It's not the toy that old toaster ovens used to be.

11. ### MatthewTouchdown! Greaser!

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Today’s testing:

It appears the controller is meant to switch one side.

I connected up to one side of the connector that goes to the heating element and to ground and measure 10.9V when heat OFF. When I don’t connect to ground and let it float I get 2.7V. With heat ON I get 10.6V and when the controller turns on the broiler element during the heat cycle that drops to 3.6V.

I repeated on the other side. With heat OFF I get 120.8V and floating I see 10.9V. With heat ON I het 120.5V and when the broiler element cycles on I get 119V.

So it looks like one side is being switched at the bake element but it doesn’t come on.

Next is to take apart the control panel to get access to the wiring diagram and control board.

12. ### steingarTaxi to Parking

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Very simple low-end oven are quite inexpensive. The mechanisms are all quite simple, the higher end ovens mostly get window dressing. Mine has a fan in it for convection and I like it, but I could live without it just as well. I'd not be without an oven for any length of time, I bake almost every week.

13. ### MatthewTouchdown! Greaser!

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@Albany Tom

Here’s what I found inside.

Two electromagnetic relays - one for broiler, one for bake. When heat is on, they switch in such a way that they are never on at the same time. The broiler is on 25% of the time and the bake is on 75% (according to the documents). This seems to match what I am observing. I did clean the carbon from the contacts, there is quite a bit of arcing when they switch.

I can see the bake relay switch but I don’t see anything happening at the element. Unfortunately, the circuit board has the touch panel mounted on the back side and it doesn’t look like I can get them apart easily to access the solder side of the circuit board. So if it is a relay, I might not be able to replace it.

I followed the measurements listed on the diagram and see 240 where I am supposed to see it. The element and temp sensor ohm out like they should (16.8 ohms and 1100 ohms).

Now I’m looking for ideas on where to look next. I’m not sure where to look at the relay or what’s going into or out of the relay. It switches and there’s power.

I checked all the connections and reseated what I could get to. Unless there’s something behind the oven, I pretty much checked as much as I know how.

Maybe somewhere between K3 and K5? If K3 doesn’t connect to K5 when it’s open, then K5 can switch (which it does) but it won’t get any power?

pics 1-3: wiring diagram

4: bake relay left (K5), broil relay (K3)

5: control board

6: inside the panel behind the control board

7: relays with covers on

Last edited: Sep 14, 2021
14. ### PaulSTouchdown! Greaser!

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Get an emory board and clean those relay contacts.

15. ### MatthewTouchdown! Greaser!

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I did that, but they are awkward to reach, I’ll try again later just to make sure. I’m getting a lot of miles in today going up and down the stairs to get to the breaker box

16. ### PaulSTouchdown! Greaser!

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It's hard to tell, are they plugged into sockets or are they soldered in?

17. ### MatthewTouchdown! Greaser!

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It feels like they are soldered in on the back side. I’m going to take another look tomorrow when I try cleaning the contacts more carefully.

18. ### Albany TomLine Up and WaitPoA Supporter

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So I've got \$1 that says it's the K3 relay. I would check the simplest thing first, and that's continuity between the broiler relay and the bake element socket, breaker OFF of course. It should be very low, if your meter beeps it should be nice and clear. Since the bake element works, the schematic tells us that there is power to the K3 relay, and also to the other side of the bake element, which is not switched. Your power measurements of about 120v on that unswitched side suggest strongly that that side is OK. That you don't get power on the switched side says there's no power on the switched side of the bake element.

Where does that leave you? Somewhere power is interrupted between the switched terminal at the bake element, and the power side of the K3 relay....or the K5 relay isn't being switched. Of all of that, I'm betting on the K3 relay because it's the most complicated. They have them wired that way so that it's mechanically impossible for both the broiler and bake element to be on at the same time. K3 won't let them both connect at once. If the broiler cycles OK, but there's never any power getting to K5, then there's something wrong with the normally closed side of K3...either lots of carbon build up between the contacts, or the contacts are burned up enough that they don't touch. With the breaker off, you should be able to tell if the contacts are open or not. Normally, I'd suggest just replacing the relay, but believe those are obsolete parts.

https://www.mouser.com/datasheet/2/418/4/NG_DS_1308242_T90_0214_T90-116266.pdf

I don't think the exact relay is listed, but it would be a form 'C' in the datasheet, as a SPDT (single pole, double throw) relay. They call that configuration a 'CO'. Close/open I guess.

19. ### MatthewTouchdown! Greaser!

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Thanks. When I was looking at the drawing and seeing the way the K5 and K3 were in series I started thinking the same thing. I’ll have to read the rest of what you wrote a little more carefully.

I’m going to tear back into it again tomorrow. I’ll see if I have a better picture of the K3 contacts. It does switch, it’s kind of fun to watch both the relays work together.

This should be with oven OFF, but I can’t remember if there was power to the unit.

K3

K5

Last edited: Sep 14, 2021
20. ### A MartinPre-takeoff checklist

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I do most of my daily cooking in the oven
I only use the top broil element
I have never cleaned my oven in over 10 years.

For my daily steak I place it on a black cast iron frying pan about 4 inches below the element
The top and sides sear and brown which locks in the juices
Browning a steak is what gives it flavor.
It takes a bit longer for the frying pan to heat up thus it cooks slower from the bottom up. Perfect.

Same for roasts but I preheat oven before putting it in
Baked potato on top rack under broil element at 400 degrees.
Turn potato halfway through and brown the other side.
Crisp skin and tender inside. Perfect . I hate microwaves.

This is not for everyone .... always some grease spatter in the oven ... not good if you are also baking cakes and cookies. Spending an hour cleaning the oven each time is not worthwhile. I never clean mine .... just sweep out the black carbon residue once in a while. I love my oven and broil element.

.

21. ### A MartinPre-takeoff checklist

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.

True story from the 1980's

Westinghouse sold millions of excellent washing machines which came with very good long term warranties.

But they had a weak spot .... sometimes the timer would fail. Housewife would contact her local repairman ... he would diagnose faulty timer .... order a new one .... install it two weeks later .... all covered by warranty and repairman fees also paid by Westinghouse.

Nothing more irritating for a housewife than to have no washing machine for 2 weeks.

Westinghouse had a yearly banquet where they handed out bonuses to employees .... top winners were from the warranty division who streamlined the whole process .... they stocked new timers in warehouses across the country .... shortened the wait times .... then progresses to letting the repairman stock a few timers in his shop .... then progressed to having the repairman carry a new timer in his van .... that way he could diagnose and fix it all in one visit.

Housewives were happy and the Westinghouse Corp saved millions of dollars in warranty costs. Hundreds of thousands of dollars were handed out at bonus time for the men who came up with the idea.

Last on the list was a dock worker who was given a small recognition award for keeping his work area clean and tidy and organized ... the executives pointed out even the lowliest employees were valued .

After he received his plaque , the dock worker took the microphone and said ....... that whole warranty problem could be solved if you simply installed a high quality timer at the factory when you build the washing machine in the first place..

.

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22. ### MatthewTouchdown! Greaser!

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Now I can get intermittent operation.

I cleaned all the contacts as best I can, then turned it on. I felt the bake element heat up and could hear some 60hz buzzing while that was happening. When that element turned off and the broil turned on, I turned the oven off, opened the breaker, put the relay covers back on, and hung the control panel back in place. I reset the breaker and it didn’t work anymore. I shut it all down and pulled the covers off the relays and tried again and it worked. I hung the control panel back in place anf it failed.

It’s leading me to wonder if there’s a bad solder joint on the back side of the board, but I don’t know if I can get to it.

23. ### PaulSTouchdown! Greaser!

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I would buy new relays and solder them in place, usually once the contacts go they are junk. It's not that hard of a job if you have done it before. The other option is to see if you can find a new or used board on ebay.

24. ### MatthewTouchdown! Greaser!

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I do think the relays work, I think the problem *might* be on a hard-to-get-to part of the control board.

I looked online and found a place locally that says they can repair it for \$120 and give a 1yr warranty. Buying one that’s been refurbished is \$184.

I think I’ll call the local shop and see what we can work out. I’ve already spent a lot of time on this and really am to the point now where I need to take something apart that wasn’t meant to be taken apart. \$120 might be a good option.

25. ### PaulSTouchdown! Greaser!

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Sounds like a good plan, I think the relays are working but the contacts are so burnt up they can't handle the current needed to run the elements.

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26. ### MatthewTouchdown! Greaser!

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That may be, too.

One problem with the pull and repair: that would leave live wires exposed unless I turn off the breaker (or carefully wrap all exposed ends, but I really don’t know if anything else would still be live), or unplug it but then I have to pull the oven. And if I keep the breaker off then I lose power to our cooktop.

I could get a countertop induction hotplate to get us by. But then we are in the same cost range as buying a refurb controller for \$185. I’m starting to think now: either get a refurb controller or a new oven. That \$185 is right at the point where it’s going to take some thinking.

27. ### Albany TomLine Up and WaitPoA Supporter

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I'm leaning with Paul on this. Bad solder joint sounds highly unlikely...the board doesn't flex, and this is a high current part. It would've failed long ago if it were soldered incorrectly. The relay contacts, on the other hand, are a wear item and visibly burned. See if you can track down a replacement relay, the contacts are most likely shot. Relay is pretty easy to swap out if you can find a suitable replacement. Original is listed as obsolete.

update - I think I may have found a replacement for the double throw relay - https://www.digikey.com/en/products...y-potter-brumfield-relays/T9AS5L12-12/1128606

I think that's close to, if not exactly, a drop in part.

28. ### MatthewTouchdown! Greaser!

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It says PC pin, through hole mount. That’s normally soldered, isn’t it? I’m going to have to find a way to get to the back side of that board.

29. ### Albany TomLine Up and WaitPoA Supporter

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Yes. You have to remove the board. That shouldn't be that bad. All of the wires on the top side of that board seem to have molex type connectors, so that either that board or the entire assembly it's a part of seems designed for quick replacement. Once you get the board out, use small wattage soldering iron (like 20-30w), and an inexpensive solder-sucker tool or maybe solder wick to desolder and remove the relay. Solder the replacement in with 60/40 or 63/37 tin/lead rosin core solder.

30. ### MatthewTouchdown! Greaser!

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The board has the component side that’s easy to access, an all the connections can be removed easily. On the opposite side is a daughter board that has the LEDs for time and temp displays. There is some sort of non-flexible connection that looks soldered from one to the other, kind of like a ribbon connector but with discrete wires that don’t look like they flex. That package then snaps into a plastic housing. The whole package is the control unit. Getting the boards out of that plastic housing is going to take some work, the plastic tabs holding the boards are pretty aggressive, and there are about 10 of them around the perimeter. I tried pulling the boards out earlier today but I didn’t have enough fingers and leverage to pull back enough of those tabs to work anything loose.

31. ### Albany TomLine Up and WaitPoA Supporter

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So the tabs have to be bent back to let the board pop out. It may be a little bit like picking a lock, in that you life up on one side gently, and pull the tabs back alternately to get them to clear/drag. That board looks phenolic, so it's not very flexible, and not all that strong. The oven will be fine if you break a couple of tabs, but if you crack the circuit board..well, it's likely not repairable.

32. ### A MartinPre-takeoff checklist

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Me again (sorry)

If a stovetop element stops working simply try transplanting a working one in its place and test it .... that way you know if it is the element or switch that has failed.

Same as oven elements ... broiler element is shaped different than bottom element but both plug in same way .... switch them and test ... then you know if element or electronic controls has failed.

thanks.

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33. ### MatthewTouchdown! Greaser!

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I tried doing that at the control board - swapping the connectors so the broiler relay would turn on the bake element but the connectors are keyed to prevent that.

I was able to get the bake element to come on once or twice, after I had cleaned the relay contacts. I can’t remember the whole sequence but I think I was measuring the voltage across the contacts to verify they were closing properly. It may be the case that the meter probe added some pressure to the contacts to force a better connection and that allowed the element to heat.

34. ### A MartinPre-takeoff checklist

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But what I meant was switch the elements themselves right in the oven compartment ... without touching wiring at the back.

On my oven there is a small plate with 2 screws to hold element in place ... remove them and the element slides out .... the contacts are similar to stovetop elements ... slide in and out ... plug in and out.

Hope that makes sense.

I recall you may have said both your elements come on intermittently (alternate from top to bottom) when you turn your oven on .... you may have a more sophisticated system than mine.

.

35. ### MatthewTouchdown! Greaser!

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The problem with simply swapping elements is the broiler hangs from top of the oven, there isn’t a good way to support the bake element. The 2nd problem is the risk of pulling off the connections behind the oven when I pull the element out.

36. ### ColoPilotLine Up and Wait

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Time for the bush fix. Pack the relay contacts with tin foil, wrap it all in electrical tape, add some duct tape on top for good measure and put it back together. When you want to use the oven, you flip the breaker on, oven heats (probably to 1000 deg). When you're done with the oven, flip the breaker off. Eventually the kitchen will burn down and the insurance company will pay for the new oven (and kitchen remodel).

37. ### MatthewTouchdown! Greaser!

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When heating:
Bake comes on for some amount of time (mine doesn’t, or is intermittent)

Bake turns off and broil turns on for some amount of time.

Broil turns off and bake turns on.

The book says it should be something like 25/75 broil to bake.

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38. ### MatthewTouchdown! Greaser!

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I like this: Go big or go home.

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39. ### bluesideupPre-takeoff checklist

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Hi.
If the Igniters are the same try swapping them.
If they do not get to the proper temperature, must be white hot not orange, it will never turn on.

40. ### Albany TomLine Up and WaitPoA Supporter

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I do NOT suggest running a gas line into the electric oven.

But seriously, to fix this, I think the next step is to replace or repair that control board. To put it in airplane terms, your engine might be OK, but if the constant speed prop doesn't work and is leaking oil, you kind of have to address that before expecting a successful take off.