I'm presently repairing a microwave oven with same problem. I have watched several "instructional" videos regarding the matter and this particular video explained to me very well the flow of current and why the circuit breaker gets turned off. Other videos just simply say that it's the switches and just replace the "monitoring switch". I'm more confident now in testing the microwave once I get all the parts put back to their original location. Thanks for the video.
Thanks for this vid. Installed a new microwave for a friend and noticed the old one wasn’t two years old (Frigidaire Gallery) they didn’t want it. Took it home found your video and sure enough the monitor switch was stuck in the closed position. Thanks.
Thanks for this great video. This was my exact situation with my Kenmore, including the switches having too much play in the bracket. Changed the bad switch, and epoxied all switches into their optimal position in the bracket. Working fine now. If I have more issues, I'll order a new bracket and switches.
Thanks , You are the only person to notice the worn switch holder bracket. Thanks to you, and Ebay the Microwave is up and running. Thanks for sharing your knowledge. Great Work !
@@edheuston673 This one failed because it was installed above a gas range. If you have a gas range you should NEVER install an over the range microwave. The reason is the heat. All that heat from the gas combustion goes right under the oven and heats it up really how, which causes the plastic parts to get soft, and will eventually deform. This never happens on an electric or induction range. If you have a as range the only thing that goes over it is a high flow vent hood / fan.
JB Weld is incredible stuff. I imagine that it might actually make a permanent repair on that bracket. I once used it to repair the arm on my office chair that had snapped off completely from the vertical section just underneath the arm pad. I apparently had a habit of leaning my body to one side while watching videos and it proved too much for that single arm over time. I gathered the shattered remnants and jigsaw puzzled them together along with some popsicle sticks for vertical bracing and JB welded the whole thing together. The arm never gave me any trouble after that despite hanging on it for years after. Eventually the bolt that held the arm to the underside of the chair started giving way :D Of course by then the chair had really had it and I replaced it but that made me a JB Weld believer.
Thank you for a great tutorial. Fixed two microwaves with bad switches. A bad switch can be fixed as well, after removing it just open it and free the contacts, put back and it works great. No need to buy a replacement switch.
Thanks for making the video. The best tutorial on the subject from someone who is authorative. I replaced my monitoring switch 3 times in 3 weeks. I found I have the exact issue with the switch block in my microwave. Seems like a very poorly designed part intended to perform a precise function.
My boss was cheap on tools too, we made a lot of our own stuff with the grinder wheel in the back of the shop, we used to replace all the switches with the bracket so we didn't get a call back on the unit, I hope you can still get the part for your neighbor
Thank you so much for the great video . I was able to change my switches myself after watching your video. The repairs would have been $450.00 my parts cost me 107.00 .i saved $350.00. Hugs to you .
What an excellent video, really well done an enabled me to solve my problem with a minimum of pain. Turns out mine was the switch but it sure was nice to see how to get the bracket out which made the replacement easy peasy. Also I really owe a big thanks to the Parts store guy who gave me a "generic" switch (6.60) vs the Frigidaire part (61.59).
I would still be wary of the plastic bracket that the switch mounts on, especially on over the range units mounted over a gas range. The heat from gas combustion really heats up the cabinet, and causes the plastic to get soft and go out of shape slightly so the monitor switch, which is normally held open when the door is closed, to short and weld it's contacts shut while blowing the fuse. Seen dozens of them fail, all mounted over gas ranges.
Plastic parts wear out. That is a fact of life. When I was in the business I changed hundreds of these door hook brackets. Didn't take long to find a replacement part. Only problem is it is 3 weeks away, so I put the unit together and it sits in the corner waiting for parts. Probably won't make a video of changing it, as it has already been shown.
If it was my personal microwave, I would drill holes in the plastic perpendicular to the worn groove and epoxy a (cut) nail in place. That way the door latch wouldn't wear out the epoxy. Since this is for someone else, I would avoid liability by not re-engineering the switch bracket. Sometimes my microwave doesn't want to start until I jiggle the door. Thanks to your video, I know more about what to look for.
cat's whisker That's why I perfer units with an open button so there is less stress in the door hook and bracket. The button lists the catch and the door then pops open.
Very helpful video. I'm having basically the same problem with my GE JVM3160RF3SS - the breaker pops when closing the door. Each new short switch I put in gets fried too. Going to order a new bracket. Do you have a recommendation on door switches? The actual OEM primary and secondary switches from GE are $45 a piece, whereas what seems to be the exact same switches (Dongnan KW3A 16A 125V/250V ) are on Amazon for $10 a pair. Are the OEM ones actually better?
Thanks so much for explaining the middle switch. From your explanation the middle switch ( NC ) when button is out the switch is on, and when the button is pressed in the switch is off. On my middle switch ( NC ) when the button is pressed in I have a reading. I replaced the switch with a brand new one and it does the same, when I check it with meter ( when the switch is not connected in the microwave both switches do as they are suppose to. I thought that maybe the switch was not pushed in all the way not making contact when i closed the microwave door but I removed the switch tapped the switch button down it still shows its on. if I remove the wire from the com on the switch it works.Thanks againRead more
to diagnose known short-circuited devices like this one would it be possible to have an extention cord with an RCD that is tripping a bit earlier than the main house one so you can easily reset it without needing to run through the house to reset the main one ?
Thanks, great video. I had the same wear on my switch bracket (Frigedaire). Brackets are the same for almost every brand. How about putting a light lube on the bracket? Wouldn't that reduce the wear?
You have a good chance that this microwave cross references to a common brand. We had a Kenmore stove that was choc full of GE branded components on time. We ran it into the ground. GE made several fridges with the same style of door handle as our Kenmore. Back in the day, Whirlpool probably made more window air conditioners years ago under the Sears brand names than they did their own.
This was just a temp fix as the bracket took 5 weeks to order and the neighbor wanted to use it. It was swapped out once the part came in. Then the house was sold and the new owner remodeled the kitchen and threw out the microwave.
Great repair, the j.b weld will last, it's bloody hard stuff :-D A dab of vasolene/silicone grease to the hooks may cut down the stress/friction. I don't like the hard way the door has to be closed to make it close, the door spring is likely too strong. It's a shame that they ruined a good microwave with a crude lock operation :-(
I had the same problem in my Black and Decker oven after ten years but I just heated and bent the plastic parts and it worked again for another few years and is still running today.
12voltvids I opened the door after using the nuke multiple times today and as I opened it it blew the breaker again. I checked the switches and they’re still good.
great video! I would also like to add, it would be wise to make sure there is continuity across the pliers before discharging your capacitor with them. You can never be too safe. Maybe its just my OCD but I had at least one set be intermittent. You also can never know, some cheaply made pliers might have a plastic washer spacer between the jaws.
There are other ways you can discharge a capacitor.If you don't feel safe doing it with pliers then simply use a method you prefer but don't let it detract people from the very good video made once again by 12 volt vids.Clearly you can see he has years of experience fixing appliances and he is passing it on to others very very well
@@Hobbyscrapperaustralia not detracting at all! We're just neighbours helping neighbours after all Even the most knowledgable can make mistakes You can never be too safe is all.
Frigidaire microwave display not working. Model FPBM307NTF Unplug microwave. Open door. Remove 3 phillips screws at the top, remove black vent trim. Disconnect electrical plug at top of door. Lift door off hinge points. Gently pry off plastic bezel. Remove 4 phillips screws. Mark locations. Gently pry each plastic retaining clip (14?) holding the metal glass frame and insert thin metal shims between frame and clips. Lift metal frame and glass assembly out. Cut back the protective sleeve and inspect for broken wires. Cut off plug. Discard broken wire sections. Solder new extensions to each wire. Cover with shrink insulation. Re-solder plug. Temporarily rehang door and plug in connector. Test control panel before final reassembly.
Would it be wise to put some kind of weights inside to keep my microwave from sliding around while operating it and opening and shutting the door? Our 2018 emerson crapped out on us and I bought a brand new mainstays700watt. It works great its just that it slides around. If I can avoid having to open it up to make it heavy that would be great. Where can I buy some adhiesive rubber feet that are grippyer than the ones it has?
A little Vaseline on the door switches latch would help make it last longer and easier to close & open. The door seems to require heavy slamming to close ... Good troubleshooting!
They are all like that. The reason these fail is due to high heat when installed over a gas range. When over an electric range they don't fail. Why? Gas range produces much more heat from gas combustion.
@@12voltvids I was thinking the same thing. I think that call that under-engineering. LOL I have a 1200watt counter top 2006 Elite that act's perfectly, but won't heat. I had done main course meat, threw a potato in on auto , then frozen veggies and the veggies came out frozen and the unit had started getting loud. Did the reset plug, unplug and heard a sparking pop sound from around the transformer. Tried some water, it sounded normal again, but still no heat. Checked out switches, mag, cap, diode and the trans "seemed" to test out okay. Everything appears to work normally with exception of heat. When I cracked it open, drained cap, .nothing looked amiss burn wise and I didn't see or smell any smoke. I'm stumped and taking somewhere would be a waste since a diag and repair would cost as much as a brand new unit ($150), more if it's the trans. Any clues or tips? Thanks.
I have a kenmore here no heat and i check switchs are ok . I see no have 120v when start in the transformer i check the relays and didnt have continuity . This model have 2 relays the high and low . But i dont understood squematics. So for test i jump the plug cknector goes to the low relay and the heat cames again. If i do the same as the high relay the microwave didnt power on. So i believed the issue its with the low relay? I change for another and didnt work. What you think?
Great teaching video. The oven looks almost identical to my Maytag unit . Where do you live that they have appliance parts? None here that I know of in Spokane, WA area.
Great video!!! I learned quite a bit about the sequencing of the door switches. One question about the monitor switch though. With the wires removed mine tests normal. But with the wires connected it tests in the closed or shorted state with the door open or closed. This is due to the wires that connect to the switch test closed. This doesn't seem normal to me. Is it? Thanks in advance.
The monitor switch is normally closed. So out of the microwave it will measure dead short until you push the button. That is opposite to the main interlock which will be open, and will close when you push the button in. Door open the monitor switch is closed, door closed it is open. You need to unplug the harness to test, as other things in the oven will give erroneous readings, such as the primary winding of the low voltage transformer for the timer. Unplug the switch to test.
I have the Lowes version - Model FGMV176NTF Serial KG72306668. It was manufactured in June of 2017, and I've had it for about two years. It'll run for 1 or 2 seconds and shut off. Still trying to sleuth an answer for that one. Any idea? It doesn't trip the breaker.
Thank you for your video. I like your video. Question: What are the functions of the top switch (NC or NO), middle switch (NC or NO), and bottom switch (NC or NO)? I might have the same problem as you had for the middle switch. So, what type of switch should I get, NC or NO?
I have this microwave that is going back to the 1990s . A big bulky Trisaty It has never gone wrong since . I used to use it for Defrost only . Now I do not use it for food . If only TV & Hi Fi would last as long as this thing
Sears is not out of business in the US. We still have a Sears hometown store. Sears doesn't make their appliances anyway. Most are Whirlpools though the microwave probably isn't.
Fridgidaire was a GM product up until they were sold off in the late 70's. Electrolux is not a GM company, as seen by this breakdown of their ownership; www.electroluxgroup.com/en/ownership-structure-392/
I didn't know the switches would actually cause a short but I haven't worked on many of these; but I do get that a shorted HV circuit isn't going to do anything worse. I've seen new microwaves that have interlocks that don't click in unless you push hard on the door. One unrelated problem that concerns me is that I've noticed what seems to be venting capacitor smell several times. I didn't know where it was coming from for months until I traced it down to the microwave (I had though my relatives cat had issues but that wasn't it). Maybe another case of "nope, that was fried electrolyte" but I don't know if it was the high voltage cap or another one or something unrelated. After a while the smell was gone. And I know I've smelled this other times, other places so I wonder about food contamination and shorts. I'm guessing the power output would decrease if the cap went bad... but would that change the amount of power drawn? Maybe not?
I make 4kV on average to the magnetron if we consider that the hv diode and the hv capacitor conform a voltage doubler. The power transformer output voltage is around 2kV. Thanks for sharing.
Our Microwave is not blowing fuses, it just does nothing, as if it were unplugged. When it first went out we assumed the Microwave was trashed, but the next morning it was back on and worked fine . It went off again that same day but came back on later in the day and has worked fine for about the last month, but when it shut down the last time that was it. The fuse and the door switches appear to be working properly and I have power at the outlet. Any ideas would sure be appreciated. Thanks, Ray
Vi there! Great video! Question: my fuse is fine and all the switches are ok but the microwave seems to not power up ( nothing) … how do I diagnose a fail on the front monitor (dial and led lights)?
My fridgidaire kept popping the breaker. So i purchased a three pack of door switches. Installed them, now not popping the breaker. But when i close the door it starts running on its own. Clock and control panel functions all work . Just runs as soon as the door is closed.. Is there anything i'm missing?
Loud hum or buzzing and no heating could be the magnetron. Unplug the magnetron and power up and see if it still hums. If not then magnetron is shot. If it still hums then likely the hv diode. Now if it doesn't him indicating the magnetron is likely shorted the red leads will be charged to about 4000 volts so you will need to leave it for a few minutes for the internal resistor in the capacitor to discharge it or better short it to the chassis to discharge. Always use insulated tools that have been inspected when working on microwave ovens. I overlooked this important safety measure once. My pliers had cracked insulation that someone had taped over. I got bit, it threw me 5 feet. Actually i had to jump to break the current as I could not let go. I was following safe servicing procedure. One hand in pocket and wearing rubber soul shoes so I was not at risk of electrocution. Had someone touched me that would have been different. The pliers were damaged and my hand (same one) touched ground and my hand clamped down and i couldn't let go.
Here is the problem.....they are opening the door to pause the microwave instead of hitting PAUSE on the key pad and then opening the door. If you yank that door open when running and the door opens uneven or the bottom latch switch disengages first....you get a power serge to that switch you replaced. They put PAUSE on that key board for a reason and people are just pulling the door open to pause it instead of cutting the power with the pause button THEN opening the door.
Hope you can help me. Fuses kept blowing on my microwave. I thought it was the capacitor. So I changed it. Still the fuse blow after trying to cook something. Now the problem can be the switches?
I'm not surprised that the switch bracket had a problem judging by the amount of force needed to open and close the door. Bad design there. You may be able to order the part on the Sears website if you can't source one locally. The trick would be to find out who actually makes the microwave as I'm sure there are many of the same model with different brand names on them all made in the same factory in China.
Hah! like when I had to get a display for my Emerson 32" flatscreen tv. Couldn't find it anywhere! But, then after seeing the EXACT SAME unit for sale at walmart again, rebranded VIZIO, I found one online. Works now...
Great explanations. I have a very similar unit. My unit seems to operate normally, but does not provide any heating. The fuse is good. Any recommendations or videos that show troubleshooting that?
Does it make any strange sounds? I don't want to give advice as far as measuring any voltages around the transformer due to the extremely high voltages involved. I was whalloped by a microwave and it threw me about 6 feet trough the air.
@@12voltvids No strange sounds. other than the food not heating, you wouldnt know that the microwave wasnt working properly. i pulled the cover and verified the fuse was good. in order to get to check capacitor, diode or magnetron i would have to remove this thing from its mount it appears. dont know that i am willing to go through that. I did not do any checking of the door switches. this is a new microwave that was installed prior to us bying this house 4 months ago, and was working fine until just days ago.
@@erichirschfield5779 You can put an AC volt meter across the primary winding on the transformer and see if the 120v comes on when it is supposed to be heating. This is the smaller winding. The larger one with the red wire is the HV side. Stay away from those. If the meter shows 120v AC and it isn't heating then the magnetron could be bad. If no 120v when you press start then either you have a bad primary switch (top one) or bad crimp connector or bad relay on time board or bad timer board.
Hey thanks for the info I’m a Hvac technician by trade and i have a Frigidaire microwave and I’ve had to replace the fuse a few times and I haven’t dug into the cause of the blown fuse yet but it happens a few days after I replace it. When I close the door it randomly blows the fuse. Thanks for the info
I have a micro oven, Model-D90D23AL-C2. When I open the door the oven tray motor starts to turn. And when I close the oven door, the power does not come on the display. Please help me.
I'm trying to figure out whats wrong with my microwave. Everything works but no heat. I put in a new diode, and new door switches, but still nothing. I checked everything, magnetron, capacitor, etc, which all arte fine. It's driving me nuts that I can't fix this thing.
The middle micro switch, (NC COM ) when I test it with my Multimeter I get a reading when door is closed and open. Do I have a bad micro switch? What does the middle micro switch control? Replaced the micro switch it does the same thing When I remove the wire from the com terminal on the switch the meter shows OL wire on shows reading closed and open .Thanks in advance
The middle seitch with the NC and COM terminals is the fail safe switch. It's job is to put a DEAD SHORT across the line to blow the fuse IF the top primary switch fails to open. When the door is closed the switches are all pressed in. The top switch, the primary inter lock is a NO or normally open switch. When the button is out that switch is off, when the button is pressed in the switch turns ON. The middle fail safe is a NC or normally closed. This means when the button is out, the switch is on, and when the button pressed in the switch is off. As you open the door the top switch is released first, which cuts the power off. As you continue to pull open the door the middle switch is released, which closes the contacts. As the primary switch is already open nothing happens. If the primary switch fails to open first, the fail safe, also called the shorting switch or monitor switch closes, puts a dead short on the line, and blows the fuse. Generally this is a 1 time deal. When it shorts it usually welds the contacts shut and needs replacing. On these Frigidaire units, the plastic bracket wears, and causes the fail safe to short before the other switch opens. It is the culprit, and needs replacing. I did another video on this unit once the replacement part arrived. The temp fix on this lasted long enough for the replacement part to be ordered, but now it has a new part installed.
Thanks so much for explaining the middle switch. I called and emailed LG and asked for schematic's( wiring diagram ) they said they would not release to the public. From your explanation the middle switch ( NC ) when button is out the switch is on, and when the button is pressed in the switch is off. On my middle switch ( NC ) when the button is pressed in I have a reading. I replaced the switch with a brand new one and it does the same, when I check it with meter ( when the switch is not connected in the microwave both switches do as they are suppose to. I thought that maybe the switch was not pushed in all the way not making contact when i closed the microwave door but I removed the switch tapped the switch button down it still shows its on. if I remove the wire from the com on the switch it works.Thanks again
@@JimMcLaren1950 All the manufactures are getting that way. They only release information to their authorized service people. It has been like this for a long time. Back in the 80s anyone could order a service manual. But once it got into the 90s when stuff started to go onto computer it became more difficult. I actually have several of the cds that Sony and Panasonic released as I had a subscription at the shop and made backup copies of the cds. I hung onto the CDs. I have hundreds of full manuals on CD.
I have seen inside those switches before. The one that went bad here looked to be sealed, but the ones I saw weren't. They aren't that complicated; just a couple strips of copper. How do they even go bad?
No actually it is installing it over a gas cook top. Gas cook tops produce a tremendous amount of heat just from the gas combustion. As this is over the range that heat quickly heats up the oven above it and causes the plastic door bracket to get soft and it wears out quickly. Had it been an electric or induction range this wouldn't have happened.
I just had my unit quit. It sound good but it does not heat. The capacitor seems good and I could read the side and it said .9 but could not read the rest. I checked it and got .924 UF so I think this is good. I cannot get a reading with the diode in either direction. I replaced the magnitron 3 years ago and all was good. I am going to the parts house Monday to get one of the high voltage diodes but was told it might be good but the meter might not have enough voltage to read anything. Thoughts? Thanks for your videos. It can't be the switches in this instance I beleave as it starts and acts like it is working as usual, but no heat.
Generally when the stack doide goes bad it will him like crazy and not heat. When the caps fail they usually short and that will blow the fuse. Are you getting 120 volts ac to the primary side of the transformer when it should be heating. B
Thanks for taking the time to answer. I found a video that showed how to test the diode with a 9 volt battery so it is good. You mention humming. It always seemed to hum loudly as the wife always complained. The afternoon I tried to reheat a burger and all seemed good but it did not heat it, if anything it barely warmed it after 3 times the normal to heat it to the point you could not eat it.
@@12voltvids Like the old person I am trying to still learn, I checked all the connections for shorts as the fuse on top of the kenmore was not blown. the secondary was 166 ohms, coil at 110 connector 2 ohms, 1.6 ohms at the coil to magnitron connector and out of range on the magnitron disconnected. Then you asked about the 110 at the coil input. Nothing! I guess I need to check the board in the front. Funny though, I disconnected the transformer and everything to the magnitron, don't want to cook, The front panel acted as though everything was correct, lights came on inside and count down started but nothing on the power lead to transformer. Thanks for the lead, but I have the worst fear it is the magnitron again though. Back to the work table. Thanks for the help. You always make it look so obvious and easy!!!!!! Thanks again.
@@amtpdb1 If you have high voltage and no heating then about all it can be is the magneteon. It is a tube. Give it high voltage and filament voltage and it will self oscillate and generate rf.
Thank you for the great, very informative, and well explained video. I really appreciate it and it was very helpful. The one thing I really wanted to see of your repair is where exactly did you apply the epoxy and in what amount?
I tried to put on JB weld, but there did not seem to be enough surface area to build upon and the "patch" just fell off ... has anyone figured it out ?
Switch was about 5.00 at the local appliance shop. That plastic bracket that I glued to get it going was over 50 and it took 3 months to get and then I had to do it all over to change that. 3 months after that was done the neighbour sold the house and the new owner renovated and scrapped all the built in appliances so this unit went in the bin shortly after it was fixed.
Even though Kenmore Appliance are kind of similar to like Whirlpool Appliance, which some models are different, though some parts might be the same, and some might be different.
I just bought a used microwave from the FB marketplace. Mine stopped working and I didn’t want to spend the $ on a new one because I’ll be selling the house soon. No manual and I CANNOT figure out how to even set the clock! Found a video that claims all Frigidaire microwaves clocks can be set the same way as what is shown on the video- it isnt working ☹️
At 14:30 you talk about when you close the door and then it sounds like the microwave is working. That's the problem I'm having right. Even though the counter says 0. It still makes that humming noise. So I just unplugged it.
