Monday, December 26, 2016

A Switch, a Switch, my Kingdom for a Switch

High-end Panasonic NB-G110P Quartz Element Toaster Oven: it is well designed for a toaster oven in that the pushbutton power switch is low voltage, indirectly activating a solid state relay that energizes the heating elements. But it occasionally wouldn't energize the heating elements unless you tapped the power switch lightly.
2020-07 Update: The second switch I installed was starting to exhibit the same symptom as the factory SW15 switch, so the first thing I recommend now is: unplug the toaster oven, pry off the grey plastic on-off button to expose the head of SW15 and apply some electrical contact cleaner (CorrosionX or MG Chemicals Super Contact Cleaner or something similar) or, less ideally, 91% or better isopropyl alcohol to SW15, work the switch a bit by turning it on and off a lot (still unplugged) and see if that doesn't fix the problem.
(If contact cleaner on SW15 doesn't work go to the steps below.)

It was an easy disassembly, the circuit board is cleanly laid out, and Panasonic makes parts available (hurray for them). The low quality electro-mechanical pushbutton power switch (SW15) is the one thing wrong, yet is only available by ordering an entire circuit board for about the price of a whole new toaster oven. (I think the part no. for the whole board is Panasonic ABR10A175 "Panasonic Pc Board".)



In this instance the switch was disassembled, cleaned and adjusted and reassembled, but not without tiny springs and other internal switch parts flying around and several hours of fussing and cussing with surgical tweezers: not for the faint of heart; soldering in a new switch would've taken a fraction of the time. It's working again, but it feels like a Pyrrhic victory. Despite being well designed this toaster oven (like many other things) turned out to be only as good as its weakest link, which in this case turned out to be its low quality pushbutton power switch.



2020-01 UPDATE: After a while, the switch failed again and I decided to replace it.

The SW15 switch on the Panasonic NB-G110P toaster oven circuit board measures about 6.13mm square at the base (suspiciously close to 1/4” square.) It isn't a perfect fit, but a fairly common 7x7mm 6-pin DPDT (dual-pole-dual-throw) switch will work as an acceptable substitute.

Search on Amazon, eBay, or AliExpress for something like:
"7x7mm DPDT 6 Pin switch"
and you'll see switches that look like the one above pop up. (Typically with a blue switch head instead of a white head.)
(Many low-cost low-quantity sellers on AliExpress if you're willing to wait for shipping from China.)
IMPORTANT: Make sure you purchase an on/off or "locking" version, NOT a momentary version.

NOTE TO Panasonic (and other manufacturers):
1) have component-level parts available (or provide information on and access to component providers)
2) Use a durable, high quality power switch (after all, that's the switch that's going to be used the most) OR design future devices so the switch is easily serviceable (or even unnecessary.)


16 comments:

  1. This is a long shot but just in case-- My beloved panasonic of the same model has a quirky "toast" button. Looking at your photo of the circuit board I assume it's similar to your switch issue except it's the little blue switch on the far left. Can I buy one of those somewhere and just swap them out? I too have tried fixing switches and had the little springs leap out and disappear so I'm not going down that road again. Thanks in advance!

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  2. The switch I replaced was on/off, the other switches (i.e. the toast button) are momentary. You'll have to figure out how to order that switch on eBay, alibaba, digikey, mouser, etc. Let us know what you find out.

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  3. hi! I'm having this same problem, and it looks like panasonic is now selling replacement buttons! https://panasonic.encompass.com/model/MSCNBG110P (scroll down it's the first item in accessories) pretty good price if it works!
    any advice on replacing the button? thanks!

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    Replies
    1. I'm pretty sure that's the cosmetic plastic button in front of the switch, not the switch itself.

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    2. You are correct. I ordered a "switch" and all I got was the plastic button in front of the switch. And that, only after they doubled the shipping price that I'd agreed to.

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    3. Is there a hack to fix the toast button switch? Or replace it without replacing the entire controller board?

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  4. did you ever get a reply to this? I have the same problem and would buy the switch if I had any idea how to install it.

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    Replies
    1. Do you know how to desolder the switch and install another one? That's what I did.

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  5. I'm having the same problem with the power switch! Rather than go your route I would like to order the switch and solder in a new one. Where does one go to get a switch like this?

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    Replies
    1. Please email us directly at fixitclinic@gmail.com for an answer.

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  6. I replaced the SW15, and the problem has been fixed.

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    Replies
    1. Does this mean you replaced the switch alone or the whole board? If you sourced the actual switch alone, I'd appreciate knowing where you found it.

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  7. Could this possibly be replaced with a standard toggle switch? Obviously there is a cosmetic component but I have a few toggles laying around. It seems like the original button is simply an on/off like a toggle.

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    Replies
    1. AFAIK you'd be the first one to try this, a toggle switch should work UNLESS there's some sort of logic that triggers an electronic relay somewhere else.
      I state this because I've noticed that a faulty pushbutton switch in the "on" position (i.e. LED is on but oven is not working will sometimes start the oven heating just by tapping or touching it lightly: others have reported the same thing.

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    2. Though I am only self taught in electronics, the constant "on" LED indicated to me, something more than just on/off. I will be replacing the whole switch with the suggested one. I should have re-read this before disassembling the switch as the parts went flying as predicted. I would like to put it back together for the time being, until the new switch arrives. I found one piece that shot out but I am not sure if I should be looking for more. I only have one little copper "slider" that looks like it rides the buss bar thing. Should I have two? It seems that way. Thanks

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    3. 86 previous question. I swept the garage and magically found the piece. I have reassembled the switch and it is working correctly. I have a new switch on the way for when it fails again. Thanks for this post!

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