Question for electronics gurus...trying to fix my microwave

I had a door switch go out on my microwave. After removing the control panel cover and board I must have pulled it out just a little too far. Now I’m not sure which wire goes where…black/white/red or black/red/white? Was hoping there was a universal standard for this. I suppose I can try guessing…50/50 chance.

It plugs into this.

Red to red, black to black, blue to bits!

(Sorry, couldn’t resist!)

are the plugs to the other switches similar enough in design to use them as a reference?
Usually there are two or three switches.

Don’t worry…I was thinking the same thing.

Well, what broke doesn’t actually go to a switch. Tried tracking it, but the wire goes way back. Just comes in and ties to the main board. No other similar plugs on there either.

First thing I’d do would be to examine all broken ends under high magnification to see if I could detect the matches.

I don’t think there is any universal standard, but I’d be inclined to say black, white, red. My reasoning is that black is likely ground and red is likely power, and good design would be to have as much separation as possible between them on a connector, but there are no guarantees on that. It would help if you could find out where the other end of that cable is going as that could offer additional hints but like you said you have a 50-50 chance of getting it right the first time!

Good luck!

It might help to show what’s attached to the other end of the wires. If we can determine whether this is a power-ground-signal, power-signal-signal or ground-signal-signal type device, then we have more to go on. Also, you can use a DMM on high ohms range to probe between the socket pins and ground / power, it’ll help match up what wires should go where.

KuoH

cut the red wire

Figured I’d check BLF while my soldering iron is heating up. The thing that bugged me is that I’m usually not this careless to allow wires to pull off when taking something apart. Plus, I really didn’t think I pulled the board out far enough to put that much pressure on those wires. Then I remembered we had the mainboard replaced under warranty about 6 years ago. I’m betting the appliance tech broke these wires and they’ve been disconnected for the last 6 years. Doesn’t seem to have affected anything.

As far as where it goes…I can’t track it without taking the thing off the wall above the oven and I have no intention of that right now. I’ll have it back together shortly and will let you know how it went.

For now I’m going with white in the middle :cowboy_hat_face:

Any chance there’s a bit of wire insulation still in the plug?

Do a web search for schematics using the name/model number. If that doesn’t pan out try the circuit board numbers. If that has too many unrelated results add “microwave” (or start the 2nd search that way). If that doesn’t bear fruit, then look for the replacement board and see if one of it’s sellers can send you a schematic or instructions for installation which might tell where that wire goes. And if you’re still going nowhere seek an appliance repair forum and ask there.

There’s a fair chance that the wire was used on the original board but the replacement board could be for multiple models and that wire may not be used with yours. And if all else fails give it a try as-is, making sure some kind of door-interlock safety is still operating- sometimes there’s redundancy with that. My own microwave repair efforts have been limited to obvious stuff like bad door switches or a blown ceramic fuse; I really don’t know enough about them to feel comfortable going deeper what with how cheap replacements are these days.

Phil

Thanks for the replies. So far so good with my ‘repair’. The unit is 7 years old, so it will be time here before long. The breaks were clean, so no wire covering on the plug…I even looked with a magnifying glass. Also, I didn’t find much when googling the board and part numbers. But, everything appears to be in working order as of now.

:beer:

I bet you were * yourself when plugging it in. :bigsmile:

likely goes to something like the moisture or temp sensor.
warning!
deadly high voltage in nukers!
carefull!