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BACKGROUND: I have a GE glass-top radiative stove (model jp3030tj2ww) that has 1 burner that starts on high on the lowest setting and gets stuck there and a 2nd burner that only does this sometimes when I have the heat set to level 3 (~1/2 way) or higher. These are both the large pan 2500W burners. The other two (smaller) burners work as intended.

WHAT I'VE DONE: I've taken apart the stove and inspected each of the 4 infinite switches (msa-w735-gem) with a working ohmmeter. I've tested each pairwise combination of wire tabs for continuity and for resistance (ohms) in OFF, high, and low settings according to instructions such as here.

  • All 4 infinite switches performed the exact same. None had continuity in the off setting, and each registered a resistance of < 1 ohm when turned on regardless of temperature setting.

    [I will note that the L1 to P reading for each fluctuated constantly/greatly from ~20-180 ohms -- however, I have no issues with the light and am not sure how to interpret this].

STATUS AFTER TESTING: All 4 infinite switches "passed" the ohmmeter test and all behaved identically. But what gives??, since 1 supposedly doesn't work at all and another only works some of the time.

None of the contacts are stuck on any unit, and the non-working units have components that I would argue look to be in even better shape then the working units -- though, there's hardly any difference. The non-working switch lacks burn marks that I have see demonstrated on a lot of how-to videos.

MY QUESTIONS::

  1. What else can I look for on these switches to indicate that the switch is to blame?*

  2. I just can't image there is, but can any other stove component lead to these symptoms? (i..s, am I missing something??)

*Part of this is educational. I'm trying to learn more about these components, and I am really stumped as to what else could fail on the switch and how I can learn to identify it without having go the trial and error root.

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It's likely that your switches have gone bad and need to be replaced. I had the same problem on a similar model last year.

The way these switches work is with a bimetallic strip (similar to the way car turn signals used to work 25+ years ago). As the electric current travels through the strip, it heats the strip causing the metal to expand. Because the two pieces of metal that are joined together expand at different rates, the strip curves away, breaking contact. As it cools, it straightens, reconnecting the circuit. (If you listen carefully to your stove, you will hear the clicks as the bimetallic strip connects and disconnects the circuit.) When you adjust the dial between different heat levels, what you are actually doing is changing the size of the gap between the strip and its electrical contact, thus changing the frequency at which the heating element turns on and off.

In your case, most likely either the bimetallic strip has gotten stuck in the closed position, or the distance adjustment mechanism has failed. The switch itself cannot be easily repaired, so you will have to replace both of the malfunctioning ones. (While you have the whole thing open, you might just want to replace all four.) The reason all four switches show low resistance in your test is that the low voltage used by the ohm meter doesn't heat up the strip enough to make it bend.

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  • Thanks. Bimetallic strips each move fine (as expected) when the cam is adjusted with the knob, so I think they're all functional. So, you think the distance adjustment mechanism would fail in a non visible way? (is that the rectangular electronic chip looking structure on the bimetallic strip? I'm really hoping to learn to identify something visibly apparent (since electrical tests didn't help) to diagnose similar issues in the future. Dec 31, 2021 at 14:54
  • I don't know how well you can diagnose the internals of the switch mechanism. When mine started acting up like that, I just replaced it.
    – Moshe Katz
    Dec 31, 2021 at 16:42

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