Microwave Trips Breaker after Latches reset - Frigidaire FFMV1846VSA


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Old 12-20-22, 12:56 PM
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Microwave Trips Breaker after Latches reset - Frigidaire FFMV1846VSA

So, at some point last week my son stuck a knife (or something) into the latch...receivers (?) on the microwave case (this is where the door switches connect and trigger the latch switches, inside the microwave - Parts #81 and 82 in the link below). This immediately tripped the circuit breaker (note: The microwave is the only device on the circuit and the outlet is NOT GFCI).

Since I was unable to release them from the outside, I had to take the unit apart somewhat to flip them back manually, and to gain access I had to take the control panel off, which meant disconnecting all the wiring. Most of the connections could only go back where they started- Only the two connecters coming from the latch switches were interchangeable, and unfortunately I made the mistake of not taking a photo so as to remember which was which and in what direction they connected.

Now, anytime I plug in the unit and try to flip the breaker back on, it immediately trips it again. Since I wasn't sure how the connecters should be, I tried all eight (8) different configurations, and all of them trip the breaker still.

What am I missing here? Do I need to discharge the capacitors for the microwave generator? Could the switches or relays have been damaged or burnt out by one of them being "triggered" without the other?

Any advice would be appreciated... I'd rather not pay a repairman $200 if I can fix it myself. The switches and relays are only ~$10 each

Frigidaire FFMV1846VSA Parts | Reliable Parts
 
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Old 12-20-22, 01:58 PM
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Discharging the cap should not be necessary. Does the breaker still blow if you leave the two interlocks completely disconnected?

Looking at the wiring diagram, it's hard to see how swapping the switches could cause the breaker to blow. I think something else got messed up. Look carefully at everything you disconnected/moved. Look for a wire or part of the control board that might be touching metal somewhere.

The two wires from each switch are interchangeable, circuit wise.
 
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Old 12-20-22, 04:07 PM
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I will have to try it with them disconnected but I do believe it tripped even so.
 
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Old 12-20-22, 07:44 PM
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If it trips with all four wires disconnected..... you're in trouble.
He had the wires mixed up between switches. There is no polarity on the switches but the job of the monitor switch is to put a 100% dead short on the power line. That is a safety.

The interlock switch is normally open when the door is open and is shorted when the door is closed.
The monitor switch is shorted when the door is open and open when the door is closed.
The interlock switch must open before the monitor switch shorts. That's how the safety works.

Do you have an ohmmeter ?
Set it to low ohms or auto if digital.
Connect either probe to the H side of the plug. Find the one of four wires that shows a dead short.
That is the H wire and goes to the interlock switch.
Connect either probe to the N side of the plug. Find the one of three wires that shows a dead a short.
That is the N wire and goes to the monitor switch.
The remaining two wires should show a direct short between them.
They should be able to go to either switch as they are connected inside.



Frigidaire parts list with better schematic - pdf
 
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Old 12-22-22, 10:10 AM
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Update: The circuit did indeed trip even with the two door switches disconnected. See the image below.

Could I have damage or destroyed the monitor microswitch by having the wires impropery connected when I first tried to plug it back in, making it permanently shorted?

These:



68 # 5304509460 A B C D Switch, interlock, primary
69 # 5304520021 A B C D Microswitch, monitor
70 # 5304520020 A B C D Microswitch, secondary
 

Last edited by Miklayn; 12-22-22 at 10:21 AM. Reason: Adding IMages
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Old 12-22-22, 10:25 AM
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Old 12-22-22, 11:02 AM
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I'm a little confused. You originally mentioned two brackets (meaning switches). When I checked the wiring schematic it only shows two switches. Technically you have three switches on two brackets and the only published diagram shows two switches. A third switch must have been added as an additional safety after the unit was released. Probably #70. I'm trying to find a service manual... even a paid one. Is there a wiring diagram glued to the case ? You can check the action of the switches with a meter. Yes... they are damaged easily and can become shorted.

68 # 5304509460 "C" Switch, interlock, primary....... on bracket by itself
69 # 5304520021 "C" Microswitch, monitor
70 # 5304520020 "C" Microswitch, secondary...... both on second bracket.

Covers the tripping breaker issue but doesn't show wiring or colors.
Electrolux flash -pdf
 
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Old 12-22-22, 11:57 AM
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Yeah I mean, honestly I have no idea what I'm talking about or what things are called outside of what the diagrams say.

My son pushed in both of the latches that receive the fingers from the door, onto which the three parts (one on the top, #68, and two on the bottom, #69 and #70) are attached. I don't know which was first. And I don't know in what order or direction the two connections are supposed to go (the first image).

Would it be worthwhile just to try to replace all three of the switches?
 
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Old 12-22-22, 01:13 PM
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Without wiring on the switch.... connect your meter. It should show open or closed.
Activate it and see if it changes state.

Not a problem to change switches but if the wiring is wrong they could short again.

As I'm thinking...typically the main fuse will blow inside the unit before a breaker trips.
Yours has tripped the breaker several times and yet the fuse hasn't blown.
 
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Old 01-30-23, 07:54 AM
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So, I wasn't able to use the ohmmeter to show anything. But I did remove the two switches on the lower latch, and I was able to manually reset one of them.

Now the machine will turn on until I open the door. Then after a moment the inside light blinks, and it immediately shorts the circuit breaker (it also clicks twice during this).

What now?
 
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Old 02-02-23, 03:51 PM
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What now?
Get a new microwave! Not worth risking your life or property over a microwave
 
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Old 02-03-23, 12:06 PM
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That's not a solution and my life and property aren't in danger. Why even comment?
 
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Old 02-08-23, 08:05 AM
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Sounds like you've got a tricky issue with your Frigidaire microwave.If you're handy and have a multimeter, you might try discharging the capacitors, as you mentioned, to see if that helps.
 
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Old 02-08-23, 04:10 PM
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Welcome to the forums.
It is not a problem with capacitors.

At this point I don't think we can help you further.
I can point you towards a purchased service manual to help you with your repair.
 
 

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