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FIXED JMP28GT1AD GE Spacemaker Oven--Control Board Issue?


Premium Member
Jan 18, 2023
Bay Area, CA
Model Number
More than 10 years
Description of Oven:

General Electric Spacemaker 27” Drop-In Electric Range with Self-Cleaning Electric Oven

Model #: JMP28GT1AD

Year: Circa 2003

Controlboard: ERC WB27K5140 (AP2025145)

Description of Problem:

For the last few months, 9 out of 10 times, neither the bake nor broil elements will heat up after setting the temperature and selecting the bake or broil option. Although the display indicates that the bake or broil feature is on, there is no sound of the relay actuating, nor do the elements heat up. Instead, after about 15 seconds, the internal temperature of the oven is displayed and then disappears, leaving the display looking just the same as before the bake or broil options were selected (i.e., just showing the time of day). Interestingly, as long as the oven is powered, there is an “electronic” buzz/hum that comes from the speaker on the control board; it is not alarmingly loud, but it is definitely loud enough to rouse suspicion.

About 1 out of 10 times, the relay can be heard to actuate, and the bake/broil elements will heat up to and remain at the set temperature. If a new temperature is then selected, sometimes the relay will click and the temperature will change, but, usually, the same problem as described in the preceding paragraph will occur.


Pertinent Facts & Test Results

-The electric range works just fine

-No error codes appear on the display

-The bake element tests 29.5 Ohms, shows no visible signs of damage, and is not shorted to ground

-The broil element tests 18 Ohms, shows no visible signs of damage, and is not shorted to ground

-The temperature sensor (thermistor) tests 1010 Ohms at room temp, and shows no signs of damage

-No main fuse could visually be located

-A thermal fuse with a blue dot on it and that is normally open tested fine (no continuity with ohmmeter). There is what appears to be another fuse-like device next to this thermal fuse. I do not know what it is or how to test it. See Pic

-The control board does not show any electronic components that are burned, melted, or otherwise damaged. None of the capacitors appear to be bulging. No connections to the control board or on the control board appear to be loose, oxidized, or in any way compromised. There is but one potential blemish: the upper left corner of the display appears to have some sort of char mark, but this mark is not visible on the display when the control board is installed in the oven (See Pic).

-I tested the two main relays on the control board with a 9 V battery and an ohmmeter; both relays actuate every time, and they establish/break continuity every time. I removed their covers to look at their internals, and although there is a bit of soot inside, again, they operate just fine. See Pic

-There is a third, black, relay on the control board. It also tested correctly with a 9 V battery and ohmmeter

-Thinking that the unusual buzzing noise could have been from one of the capacitors near the control board transformer, I replaced all of the original capacitors with equivalents bought from Mouser. This significantly reduced the buzzing noise such that it became hardly audible. Unfortunately, the oven still would not function properly.

Next Steps?

I would very much like to solve this problem myself. If not, then I would like to send this board in for repair at a reputable shop. The control board can no longer be purchased, not even used on Ebay or the like. I cannot stand the idea of trashing and replacing such a beautiful piece of equipment, and having to cut up the tile and cabinetry, just because of what is likely one little component that has gone bad. And I love the challenge of finding a solution and learning about how these wonderful devices work.

What next steps should I take? What could possibly be the problem at this point?

Pic of Oven.jpgBoard in Oven.jpgThermal Fuse.jpgMark on LCD.jpgRelays.jpgRelays 1.jpgNew Caps.jpg
Thanks for the quick response and reference, Jake. I imagine that with your experience in appliance repair, you have a decent idea about what exactly the problem might be from the description I provided in the original post. Do you think I myself might be able to repair the board, or is specialized equipment likely required.

Moreover, if I were to send it in for repair, do you have an idea what the likelihood of it being fully repairable is? The last thing I want to do is send the board in only to have the same problem continue. And when technicians repair a board, do they just replace the singular part that is to blame, or is there a larger effort to replace multiple parts to ensure that the board is likely to get many more years of use? Another thing I've been wondering is why some sort of error code doesn't appear as well as what the strange buzzing noise that went away when I replaced the capacitors was.

When I originally began inspecting the board, I thought for sure it was one or more of the relays that was likely to blame. I'm still suspicious of them, but then I don't understand why they seem to work fine when testing with a 9 V battery (both when soldered to, and removed from, the board).
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Those are good questions, but I can't answer them. As techs we just replace the board, not repair the board. If the board is NLA we tell the customer the same thing I told you.
Anyone else out there with an opinion about whether the problems presented in the original post are likely caused by a control board issue, and what my options are to remedy the situation?
To conclude this thread: I ended up sending my board into Circuitboard Medics, and they repaired it for ~$225 shipped. According to them, the relays needed replacement, which is what I assumed was likely the case, even though they tested all right for me with a 9V battery. Go figure. They also replaced all the capacitors that I had already replaced (I never told them that I already replaced them, since I was concerned that they might not be willing to work on the board if they knew). They also said they removed some oxidation from some connection or another; I inspected everything and never saw any. Overall, I think the only issue was the relays. If I had had more time, I would have been a $20 fix, but sometimes you just have to move forward and bite the bullet. I'm just satisfied that the saga is over, and Circuitboard Medics was pretty professional. I only wish they had indicated what the problem was after fixing without my having to ask.
Excellent, glad to hear they fixed the board for you and its back to working good again.(y)

Thanks for the update!

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