My brother! Thank you for your video. Because of this video I saved so much $$$$$. Now that covid-19 is shutting everything down and to get someone to my house would be impossible. And having kids and wife use the microwave it saved us lol. Honestly, I do lots of research on RU-vid, however you have proven to me as my #1 now. My unit is Bosch oven and microwave in one. Paid large for it and because of you, saved large! Thank you 🙏!!!!
Sweet, just mine working! Thanks so much for posting this man!! Not the same exact problem here, but very similar. On mine, the fuse was blowing when the microwave was turned on. This vid led me to check the switches. On mine, the monitor switch was just a bit jammed up (stuck down) - pressing it a few times w/a screw driver got it working/springy again. I tested w/a multi-meter and continuity was working as expected, after that, plugged things back in, back in business. 😎👍
awesome ! Micro blew 4 fuses in the last few months...... worked for a few weeks inbetween. Today it failed and kept blowing the fuse as soon as I plugged it in. Found this video, checked the door switches and one had failed. Found replacements on amazon. A $15 repair rather than an expensive service call 👍
Really good video! Had the exact same switch fail on my 2 year old microwave! your video helped me figure out how to diagnose the problem and fix it, Thanks!
Thanks for a great video that has diagnosis, repair as well as circuit schematic explaining the failure of the microwave followed by demonstration of the success of the repair. Hats off to you, Sir.
Meowcrowaves are the best. Enjoyed the video. Educational. The points on that switch reminds me of contacts of "points" in old car distributors. Yes, and having microwave ovens over a range top is not a good idea. Not only the heat, but all that humidity from steam.
Having a similar issue.my whirlpool over the range is 10 years old qnd recently started blowing fuses the minute i plugged it in. I'll check my switches. Thank you for the good video sir
For those of you with the same issue with the door catch bracket that has worn out. I used an ABS slurry to “paint on” some additional plastic to repair that part. Worked great and saved me $30-40 for a whole replacement bracket. Acetone and melted some spare legos is all it took.
The biggest problem with these switches is opening up the Microwave while its still runner, that shoots a small current through the switches and eventually casses one or both to stick open, usually the one that closes first.
I have this exact same problem Breaker blowing as soon as i plug it in, so i should check out the door switches first, thanks for this info it will be very helpful to me.
Excellent video. I watched several because my microwave pops the fuse as soon as it is plugged in. From watching your video, I understand why. I saw several saying it is the door switch (which I will check those tomorrow) but you explain WHY the switch fails and not just how to replace. Knowing WHY is just as important as HOW to replace it. Excellent work. Subscriber now!
Mine ended up being the switch holder. Without your commentary I don't know if I would have noticed the worn latch guides! I've only had this thing for TWO YEARS and it's already worn excessively. I had my previous Whirlpool microwave for almost 8 years and it still worked when i got rid of it! (although the finish was peeling off of the handle).
thank for video .that is same microwave as ge.very common issue with them .the problem is the latch body itself has worn out that you can see in the video causing the middle switch or monitor switch not to open up and short. ge recommended to change out latch body ,middle switch and door hook. if not it will happen again due to worn out latch and hook.
First word out my mouth when I saw the title was "crowbar"... Only because of a previous video where you explained how the dual door switches work though so thanks :)
A crowbar is an over voltage protection device. Can be as simple as a zener diode set to the maximum voltage in low current applications. In high power devices a SCR triggered by a zener is usually what is used in DC circuits. In more elaborate circuits the SCR would energize and latch a relay with the circuit wired to the normally closed contacts. Once the zener activates the SCR triggers latches the relay to the NO contacts and removed power from the NC and your power is interrupted until he SCR is reset.
And this is why you have a subscriber in me! I knew it wasn't quite right to say crowbar, but couldn't think why lol. I just imagined it as a crowbar forcing the fuse to blow instead of the user's face getting roasted. I'll digest this reply & correct my terminology, thanks.
I think that the contacts of the driving relay for microwave lamp along with the internal tension spring sometimes need checking also because the contacts burned and remain stuck and the lamp keeps working without any other noticable sign.Once had this problem with the capacitor blown and the gears of the mechanical timer worn just because the relay contacts didnt open and the timer motor kept working along with the RF lamp in silent and melted the facing plastics until the capacitors short circuit.
after watching your explanation of the purpose of each of the switches i was able to figure out why mine was tripping breaker when opening the door even though the swicthes all checked ok. i always grab the handle at the bottom and jerk it open which over time has caused the shorting switch to activate a spit second before the top switch was opening. after your explanation (which i couldnt find anywhere else btw) i went out and grabbed the handle at the top and yanked it open and voila no breaker tripped!!!!
Sorry for the late viewing, my internet has been dead since last night to 11 in the morning today :-(. Speedy repair :-) My knowedge on microwave cookers is minimal, the anode of the magnitron is tied to negative (same as earth in the uk)and the cathode is connected to a negative voltage created by a high power/voltage diode and capacitor. That 5kv transformer/diode/capacitor makes the red alert bulb lightup, i dont like being zapped lol. That shorting safety switch is the most important one.
Your power was out too?? Mine was out for quite a while, from storms, I guess, not certain because it didn't go out until like an hour or more after the storm had passed.
A Three Dog Night The difference in my case is it wasn't the power that went out, the isp service just failed. Virgin media internet is a pain for having problems :-(
I still have my 1997 Sharp 1000 Watt counter top microwave still going strong. My door doesn't have a handle. You have to push a large button at the bottom of the control panel and it swings open. I plan to keep this microwave as long as it will nuke my dinner.
I still have the same one too. Sharp microwave with a push open button for the door. 1998 model. Clean quiet and strong 💪.?? With automatic popcorn timer.
Hi, and thanks for this video. I have this exact microwave and it's tripping the circuit breaker every time you run the microwave. I purchased all 3 new switches for the door and changed them out, but unfortunately it's still tripping the breaker. I think either it must be something else, or it could be the latch assembly that holds the switches. When I took out the old switches, I think I broke off the little lever that holds the switch in place with the screwdriver. Is that piece located on the latch assembly to hold the switches in place? Do you think it would be worthwhile to replace the latch? I've spent almost $100 on this microwave and it's still not working, so I'm reluctant to spend more if it won't be fixed. Thanks in advance for any help!
This is awesome!!! The comment you made about both contacts needing to hit at the same time solved my problem. I noticed that the plastic mount holding the two door contacts was push back on the bottom after 8 years of use. I realigned it and tighten it down and PERFECTO!!! Thanks for your vid!!!
Actually one has to activate just before the other does so if that is not happening due to a bad first switch or a loose switch assembly it can blow fuses when you open the door.
My oven's panel was good but it wouldn't turn on the nuke. A bad switch tested good but it didn't work as well as the other switches. I took the bad switch's cover off and found the lower contact slipped down a little that made the switch movement weak. I corrected the problem and sanded the internal contacts with fine sandpaper. The oven now works. $0 cost. If it happens again I'll epoxy the lower contact in place to keep it from moving down. My cheap Emerson was made in 2005 and works as good as new now after the fix.
Fairly easy. I just used this and was able to nail it. Read the part about understanding the results. Mine shows OL or zeros. I guess OL is open line. Basically zeros is a good connection. www.wikihow.com/Test-Continuity-with-a-Multimeter
Very interesting. I had a microwave oven that was wrecked by a "kidult" recently. He always used to slam the door and the switch (I can now tell) must have given up the ghost. I bought the same microwave again, so I will have a go at fixing it next time. as he is still living with us.
Kidult hahahaha I have 2 of those living here, and yes they tend to slam things. At least both my kidults have jobs and pay rent, so I just keep my mouth shut and hope they hand around a little longer. I have a friend that has one about 10 years older than mine that refuses to get a job, sleeps all day, plays video games all night. What happens when you slam the door is you can "bounce" the contacts, and if they are both in the closed position for even a millisecond, well, you know what happens then.
Any tips for "saggy doors"? I looked for some adjustments to the hinge mounts, but couldn't find any... top hinge seems esp. loose... a bushing, perhaps?
Good video. I was able to get my microwave working again, but if I open the door while it's running it blows the internal fuse and throws the circuit breaker. Obviously this suggests the switches on the door latches aren't disengaging at precisely the same time, but how can I determine if there's too much play in the door (there is some up and down play when I try moving it with my hands, but not sure what's and acceptable amount) or if there's an issue with the bracket that holds the switches?
hello, just saw you video and im having problems with my microwave as well. (i have the same one you have over there in the video) right from the begining I found that my microwave didnt show any continuity (1:04) (my fuse was blown but I replace it before doing that test). Later on I found a bad micro switch (the midle one) I replaced it, after that the microwave still wasnt able to show continuity, but was working ok tho. I leaved it like that and test it for a few days and by the 3rd day, blow the fuse again. I dont know what its happening
I'm thinking of the spring for the door latches wasn't so stout a lot of these problems never would've occurred. It takes a moose to open the door in all these affected models.
Great video! Our MCO1610WF blows the fuse when the door is opened. All normal until then. Likely a primary switch fault? Are the top and bottom switches both primary and the third secondary?
On most the primary it top and secondary is one if the bottom. The second bottom switch stops the timer when you open the door. The secondary is a normally closed switch. The primary and timer normally open.
I replaced my microwave switch because I was having the same issues where it would fuse together. It happened again with the new one and I'm afraid to turn it back on. Also, before I replaced it today, it started making a humming noise when I tried using the microwave with the old switch.
Is this repair something that could cause a shock? In other words, does the capacitor need to be drained? Gonna try this repair myself but I'm a little afraid..
To prevent the microwave from operating while the door is open, most do have an upper and lower door switch. Sometimes a broken or stuck latch, stuck switch, etc will prevent the switch from operating. The final switch is this "Monitor" switch that shorts the line only when the other switches do not open first. Sometimes a bad door alignment (do you slam the door?) will trip this switch first. This shorting switch sometimes stay welded shorted, but this is not a fault of the switch. It means it did it's job and the oven needs properly serviced for safety. The other switches have failed. All 3 need changes as a set as the first two failed and the 3rd protected you.
With two normally open switches in series both will be passing and breaking current so the contacts will get worn and have a higher chance of getting welded together (which would defeat the safety.) The normally closed monitor switch, on the other hand, never handles any current unless there is a fault, so its contacts will stay pristine.
Question, I had a bad OTR microwave and replaced with a new one. Then I checked the old one and find out the fuse was blown. Then a week passed and now the new one is not working. Any idea of what happened here? Thanks!
Subscribed well done man! I have a GE spacemaker overhead, the 20A fuse behind the display board was blown, I changed that the micro works for like 10 seconds then pops the fuse again any suggestion? Thanks much
Thanks for the video, but my microwave cause circuit breaker to trip after running for some time and not by opening or closing the door, Its tried at different outlets but causeing the breaker to trip after few seconds. Any solution please?
I thought the door switches were my issue as to why the fuse keeps blowing as I have the same model. I replaced all 3 switches and the black switch mount , door hook. Tested all switches with door open and closed. Still blows the fuse after buttoned up and turned on.
Heat. Gas ranges produce a ton of heat. That is why people with gas ranges have big exhaust fans. Not only is there the steam from what is cooking there is the heat from the open flame. That heat heats up the bottom of these over the range units, and when you heat up the metal, and there is plastic inside what do you think happens to plastic when you heat it. I'll give you a hint, it gets soft and can warp. I would NEVER install a microwave over a gas range. An electric or induction cook top, the only heat is from the steam, and well steam won't be more than 100'C or 212'F. The heat from the gas is much hotter than that.
Sir..while watching your video...I have planned of heating my Burger to my microwave.. It just happened.. That my microwave..makes a large noise..not the normal...and I stop immediately... I switch off..then try it again..its the same..and when I stopped it again..I smell something like burned...but the unit I still on have lights..etc..no blown fuse or whatsoever...what do you think is the problem... Thank you sir
Why does my microwave intermittently blow the fuse when the door is opened? It was not even being used. I pulled open the door and was about to put some food in. Haven't even press "Start" yet! Checked all 3 switches with the connectors removed from the connectors - all good!
Good stuff. I have the same unit. I saw an arch when opening the door (arch was at the top of the door). It tripped the breaker and blew the fuse. Change the fuse out and it powers up, but trips the breaker once I start to run it. Plan on learning how to test the lines and finding where the short is. Any thoughts? Powers up, but trips once it start warming.
@@12voltvids Talking Greek to me on primary and secondary. I did test the continuity and found that the switch you replaced had the same issue. The meter showed zeros even when I pressed the button. Any ideas on where to get the switch? I'd hate to get the wrong one. I'm guessing they are different since some sit open and some sit closed. You're awesome by the way.
@@12voltvids I think I found it. I ordered a package. Cracked the one of the bottom ones open and it was soldered together. Will update once I repair. www.amazon.com/gp/product/B08D8J6J2T/ref=crt_ewc_img_srh_1?ie=UTF8&psc=1&smid=A84ISXLWKDMPW
@@Strib420 primary is the top one on most microwave. It is open normally and closes when you push the button in. The secondary is the lower interlock and it is normally closed (shorted) and opens when you push the button in. The secondary switch job is to dead short the mains if the primary switch sticks closed. When you open the door the first thing that happens is the primary or top switch opens before the door starts to open then as the door opens the secondary or bottom switch closes this way if the primary switch does not open say it's jammed with dirt or debris the secondary switch will put a dead short across the line and blow the fuse
@@12voltvids Thx. I saw your diagram on how it diverts the flow if the switch fails. I ordered three to replace all as you suggested. In my case, it seemed as if I was not deliberate in opening the microwave (opened from the top) and there was an arch up top between the door and the panel when it popped. I will make sure to pull deliberately from the middle. I'm now a subscriber. :-)
I always knew there were multiple safety interlock switches in a microwave. I did not know there was one that direct short line and neutral I will have to remember that.
Yes definately. Fail safe. Called different things by different manufactures. Monitor switch, short switch, failsafe, secondary interlock. Every microwave over will have at least 1. Some of the older ones had 2. One on the door hooks and a second one on the hinge on the other side to trip if the hinge broke.
@@uK8cvPAq Not to reduce the chance of the magnetron being energized, but to eliminate any chance of that happening. A dead short will blow the fuse and kill the power
One of my switches was bad so I just replaced it and made sure it works but I’m still getting a short (continuity) at the plug when the door is closed. If I open it it goes away like I’m the beginning of the vid. Also blows the fuse as soon as it’s plugged in.
I had a microwave light my face up after i tried fixing it. Something was wrong with it not heating, then all of a sudden it started heating outside the microwave. my face was red for a few days. The door was closed when it ran, then it started smoking.... I didn't mess with one after that.
Then you are very lucky you're not blind by now. High power microwave energy can cause serious eye injury almost instantaneously, and blindness in a few seconds, as it heats up the liquid in the eye very quickly, because there are no veins in there to transfer the heat away with the blood circulation.
Well I was going to try to fix my mom's but now I'm not to sure. So you nucked your self. Do you have any special powers.do you glow under a black light. Or spit acid. That shit ain't funny.
My oven came with a 20 amp fuse. It was lightly use and ran fine 2 years before blowing. Should I change to 15 amp? My house has a 20 amp dedicated plug at the microwave.
I having a problem with my microwave too when I try to put time in and turn it on it just makes clicking sounds the timer is still counting down what is wrong with it
Could be the top primary interlock switch is not closing, or the relay that actually turns the power on and off to the magnetron is not working. That's about the only thing. If the fan comes on when you hit start you can rule out the top switch, and then it is pointing to the relay on the timer board, but if the fan doesn't start when you hit start, then most likely it is the primary interlock which in this unit is the top switch.
@@sdiburro1 Any appliance repair place should be able to help you. If not digikey or mouser will definitely carry them. The part number is usually printed on the switch.
What might be the worst that could happen if you had simply doctored up the old switch and re-used it? I'm just thinking that with the above-average chance that the thing will be turfed out soon, why invest in a new switch plus the drive to go get one? If it wasn't something that would be a shock hazard or a firestarter, I'd have taken the chance that it would have functioned for another few years of service.
The worst case is the switch doesn't close when it is actually needed, causing the unit to run with the door open and injuring you. It's part of the safety circuit, so it is not the place to use something marginal.
There is one middle butten on mine that doesnt want to pish its (NC) but cant push it in on (NO) no matter how hard i push. Help me please. Is that the fault
Is there any reason why removing/unplugging the monitor interlock from the circuit would prevent the microwave from running? Of course, just from a testing perspective. Seems to me if it was unplugged, circuit should would not short and 'act' as normally open. TIA.
If you unplug the safety interlock it will run. Thus us the normally closed switch that opens when it is pushed in. The other switch to it, the normally open switch shuts off the timer. The safety short switch does that, puts a dead short across the line to blow the fuse.
I could really use your help. I have a 2 year old microwave and the thermal fuse as well as the internal fuse continues to blow. My wife opened the door to the microwave before the timer was finished and it lost the power. By adding a new internal fuse it regains the power but when you press start on the microwave it immediately loses all power again and blows the fuse. After further investigation I found that one of the thermal fuses was bad. I replaced it and replaced the internal fuse and it worked great for a couple of weeks. My wife opened the door again the other day before the timer was finished and now it has no power and the thermal fuse as well as the internal fuse is blown again. What could be causing this. Thanks in advance for your help.
Year later, but hopefully this helps someone. I had the same problem - fuse blew when starting. On mine, the monitor switch was stuck down and i just had to unstick by pushing it in a few times (yes, it will likely need replaced soon). Basically u just need to check continuity (via multi-meter) on all 3 switches and make sure they're behaving :)
Welp I'm back. 4 months later.. Stuck monitor switch again. 😑 I realized the plastic hook-shaped piece that protrudes from the door is wobbly and does not press the monitor switch firmly enough. Another round of switches and fuses, plus a carefully placed bit of heat shrink tube around the end of the door hook. It has been working for a few weeks with no problems. Would not recommend my lazy fix to anyone, ever. Not really sure why I'm typing this at all actually. Perhaps this microwave has pushed me into a state of questioning all things broken or not. A sad and disappointing failure of modern engineering.. Yeah, think this recent round of microwave repairs had the side effect of breaking my mind and faith in humanity. My only hope is that there is enough spare bits of stuff nearby to kluge together something that will make reality make sense for another month or two.
Did you replace both switches? The primary and secondary switch need to be changed in pairs. Top one is a NO switch and bottom is a NC switch. There is a 3rd one also at the lower latch which is a NO switch. That is the timer stop switch. That one is generally ok.
@@12voltvids my bottom switch was sticking, like when I pressed, there was no click, so I only replaced that. Top two click fine, however as soon as I open the door it blows the fuse.
On my microwave the fuse pops while the microwave is not being used. Twice now I notice the fuse blown in the morning. And I know during the night the microwave was not used. What do you think that could be?
Good video but I have a hard time believing manufactures would put in such a design flaw that if you don't pull the door just right it will kill a switch designed to be pushed over and over again. Especially when I replace the switches and the fuse instantly pops.
You are saying that the switch failed when its contacts are welded together from current flowing through it? Have you ever proven that the switch will cause the fuse to blow if the other switch is actuated when the door is open? That sounds absolutely crazy! Isn't it more likely that something caused too much current to flow in the switch so it failed?
It has nothing to do with current flow. The system is designed so the primary switch is open, before the short switch closes. If both end up closed at the same time there will be a dead short and the result is welded contacts. Now how can this happen? Weak spring in switch causing contacts to close, excess dirt and grime causing switch to stick, but most common is some idiot slamming the door shut and causing the contacts to bounce.
@@12voltvids Sorry it has everything to do with current flow. The switch contacts are welded together. That only happens when too much current flows through them. And that is precisely what happens when the one switch fails open or closed with the other in the wrong position. The power is momentarily connected directly to the other switch which is connected to the neutral - bam - short circuit and a minimum of 15 amps through the switch - probably much more! This is an outrageous design in my book. Almost anyone other system would use the switches on a positive lock so the one goes and so does the other - there has to be a better way than to overdraw the power supply to make sure that the switch is also destroyed. I tried hooking mine to the other terminal, but then the door is seen as open when the switch is active (door is closed) so I think it is wired right as it was intended and does exactly as you stated. If the switches are not in sync, the main power is connected to the neutral and it pops. If one happens to be on a c/b, this trips the c/b rather than the 20 amp fuse, if the fuse is a good slow blow, it might not be damaged by that, but the switch even if rated for 25 or 30 amps will not take that - the pads are too small and will overheat/arc and weld them shut. The rating of the switch is meant for switching on or off, not for continuous operation in short circuit conditions until a breaker or fuse blows. I am just totally taken aback by this type of design. And that doesn't even consider the transients that the high currents put into the system with those ICs and the like - they are asking for trouble.
@@dwjw1 The whole point is they want the switches to be destroyed. It is not a bad design. It is designed so that if the primary switch sticks closed for any reason. Grease / dirt build up, someone slamming the door, switch failure, some idiot sticking a screwdriver in the top slot to try to make the unit come on with the door open, the secondary switch has a dead short on the main to blow the fuse and or trip the breaker. This will blow the switches. This is designed as a 1 time operation which will render the unit safe. That is why they call it a fail safe. The last thing you want happening is to open the door to your microwave and the magnetron stay energized and expose you to high power microwave radiation. As you are arguing about the design indicates to everyone reading this that you have absolutely no clue about how these things work and why they are designed like this. The point is to render the unit inoperable and throwing a crowbar across the supply will guarantee that the unit has no power. No consideration is given for collateral damage. Only concern is making sure the unit is dead. Better a dead microwave than exposing you to high power microwaves that will cause serious harm to your health.
Actually I have done that on my old long discarded microwave when it welded the contacts together, but I would never suggest that anyone do that for liability reasons. Those switches are critical safety components, and once they arc and weld themselves closed they need to be replaced. If you want to do that on your own unit, I can't stop you. I can only recommend replacing the switch as it is a safety device.
@@12voltvids On my microwave the primary interlock failed closed so the breaker tripped whenever the door was opened. The low voltage switch to the timer module happened to be the same model, so I swapped the two. The safety circuit got the untouched switch and the timer module got the marginal switch. I believe it should still be safe. As a side note, when the monitor switch operated it shunted the current without welding itself. It tripped the 20A breaker instantly instead of the 20A fuse. I presume this is because breakers have both thermal and magnetic trip functions while fuses are only thermal.
