Microwave

Repair and disassembly guides for microwave ovens.

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My microwave is not heating, but the timer is working.

My Frigidaire microwave oven is not heating. The countdown timer runs as if it was heating, but that's about it. Any suggestions?

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Personally I would suggest that you take it to a professional for that repair. Those things are wicked and not meant to experiment with. THEY CAN ACTUALLY KILL YOU, so take it to get fixed.

by oldturkey03

If your microwave oven stops working then you should get a professional. It could be that the power is cut off by something like a fuse failure. DO NOT tinker with your microwave oven because they can give you VERY NASTY SHOCK. IT WILL MOST DEFINITELY Electricute you.

by Tiny Box Tim

Now a days microwave oven has become common in every home. First you must have to know the trouble shooting tips so that you can repair it yourself has a HVAC trainer i have some tips for you to follow http://www.hvactrainingwebsite.com/ before repairing follow the precautions be aware that the appliance is not plugged in and do not touch the wire or components until you discharge the high voltage capacitor and do not work alone you need a professional to help you.

by Amanda peet

Here's the how to fix it yourself guide

https://youtu.be/WAf18e8sW4E

by jon

No heating microwave issue is likely from defective magnetron. If you have basic confident working with electronic, replacing this part is not difficult. There are several instructional video posted online. Just make sure you follow all advice when replacing it. I recently replaced one on my microwave that saved me hundreds dollars from buying a new one.

by hungtdao

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My first thought would be a blown magnetron. On microwaves, these can generally go dead, usually with a popping sound. I think there might also be a fuse in your microwave, but I do believe that if it was a blown fuse, your MW would not start up. The technician should also not forget the door switch since some of them can cause the same issue. My solution would be to A: Call a trained appliance technician to replace the magnetron or B: buy a new microwave. Microwaves have really gotten very inexpensive and probably will cost you less than the parts and labor for the repair. I STRONGLY SUGGEST NOT TO MESS WITH THIS. MICROWAVES ARE TRULY DANGEROUS. You do not want to fry yourself. Strictly from an academic point, it could be the power diodes or a defective capacitor. Your microwave may turn on but does not heat. Remember the frying comment above, this is the part that will not just curl your hair, but will most certainly be a shocking experience. DO NOT MESS WITH IT. The magnetron can be tested by setting an ohmmeter to its highest resistance scale. Then, touch one of the meter's probes to a magnetron terminal and the other one to the metal magnetron housing. The test should produce a reading of infinity - indicating an open circuit.

For more info check on here

Again, this is for academics only, DO NOT ATTEMPT TO FIX IT YOURSELF unless you are trained in high voltage. Good luck and STAY SAFE.

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In complete agreement +

by rj713

One must first unplug the microwave oven from the mains supply. Upon removing the sheet metal "skin" one should then "crowbar" or short out the high voltage capacitor with an insulated screwdriver. Once the capacitor has been discharged, it is perfectly safe to work on the oven and remove parts for bench testing. There should be no need to work on the oven with mains power applied.

by Milosz Ostrow

I understood that SHORTING OUT a capacitor can damage the insulating sheets within the device?? I seems that most if not all use a wire connecting the cap to earth so to drain the device.

by john a

john a, the high-voltage capacitor in most microwave ovens is bridged with a high-value bleeder resistor for safety. It's likely that once the oven is turned off and unplugged, the capacitor will be discharged long before the sheet metal housing is opened. Shorting it out is just an extra precaution.

by Phil Cooper

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Most Helpful Answer

The kind of failure described in this section could be due to failure of the magnetron tube, the power relay that supplies the magnetron tube, or the high voltage supply for the magnetron, especially if the turntable, fan, light and controls all still appear to be working.

I recently resurrected a dead G.E. Profile built-in microwave oven whose power transformer had failed in a most smoky and smelly fashion. The display and touch pad control still appeared to work, but it didn't heat anymore. The fuse didn't blow. After the oven was taken down and the skins were removed, the failed part was visually obvious. Even though it was 5 years old and well out of warranty, we were able to get a replacement transformer from G.E., and after about a half hour of reassembly, I was able to plug the oven into a heavy duty extension cord and start it up on the bench. I wiped the the oven cavity with household ammonia to remove the smoke residue as much as possible. A bit more work and it was mounted on the wall again and back in service, although it took a couple of weeks for the remaining acrid smell to fully dissipate.

Magnetron tubes are very reliable and not very likely to fail in less than 10-15 years. You'll probably get tired of the oven before the tube burns out. The high voltage transformer is the most likely thing to fail. Since the transformer has both high voltage and low voltage secondary windings, it is possible for the high voltage winding to fail, yet the low voltage section to still work and supply power to the electronic controls. The next item after the transformer is the silicon rectifier used in the high voltage DC supply for the magnetron.

The filter capacitor in the high voltage section is usually bridged by a high-value "bleeder" resistor to discharge it when power is turned off. It should be safe to work on within a few minutes after power is removed from the oven, although to be sure, one should short the capacitor terminals together with a screwdriver or other insulated tool before doing any work. Unless you are equipped with proper high voltage test gear and are trained in working with high voltages, you shouldn't work on a live magnetron circuit, as it can kill you. The reason I felt safe in tackling this job is that I'm an electronics engineer with 40 years of experience, including training in vacuum tube circuits.

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Your microwave oven not working?

I am sure tht many answers blame magnetron is faulty. Why, because is expensive and not worthit to fix. I fixed nearly 200 microwave ovens ( customers returns from shops) and only about 4 magnetrons need replacement, usualy in branded models. High voltage transformer is rare to get faulty ( about 2 out 200 ). Will smell burning smoke from apliance, it is from high voltage transformer.

First thing, microwave oven is very danger apliance to repair due high voltage. If you do not know how to deal with electric items ask specialist. On my blog will find instructions how to fix microwave oven.

The most common fault and very cheap to fix is microwave oven high voltage fuse. This part is attached to tranformer in black or white plastick tube. Need carefully open this tube using flat screw driver. Will see glass fuse, clearly will show you if is ok or need replacement. If you replace this plart, before try apliance if working is got to check high voltage diode and capacitor. If one of this parts faulty, your new fuse will burn again in seconds.

Door switches are for safety, have nothing to do with warming food.

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Door switches are so the microwave doesn't run and leak out any radiation, the fuses are slow blo 15 amp fuses that you can't see inside all micros have had them since their first design hit the market and how come your scaring the poor guy about the so called dangers of the high voltage in micros? you probably don't even know that there has NEVER been a fatality from someone fixing a microwave , TVs have 5 times more stored up voltage that micros have, you need to study the theory behind microwave operation, unless you like making the homeowner get stressed out even more than he is because of what he thinks the bill is going to be, man I

was always making the customer understand exactly how their appliance operated so they would be put at ease, knowing they didn't put a potential bomb in their house by mistake, I'm sorry real technicians get a bad name when they get confused for a repairman, I was trained to be a full line technician, residential, commercial and light industrial, micros were a hobby.

by Paul

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I have a GE Profile and everything worked but it would not heat. If this is the case with your microwave then here is what I suggest. Open up your oven by removing the top cover. Let it sit UNPLUGGED for 30 minutes or better yet you MUST discharge the HIGH VOLTAGE CAPICATOR. The capacitor has enough voltage to kill you. If you do not know what a capacitor is or how to discharge it look for a video on UTUBE. Then do the following:

1. Locate the transformer. Take of the two leads usually a red wire and a white wire and take them off. Note their locations for reattachment.

2. Take a digital multimeter with the red lead and place it into 500V and the black lead into COM. Place the rotating switch on 200V.

3. Take the red and black leads and place one lead into each of the transformer wires. Place the red lead into the red wire and black lead into the white wire.

4. Plug in the microwave oven.

5. Start the microwave.

6. Turn on the Multimeter and read the voltage.

7. If the voltage is 118 to 125 then then your front panel is working correctly. Unplug the unit and let it sit for 30 minutes to discharge the capacitor or discharge it. This leaves only four possible problems. It is either the transformer, the capacitor, the diode or the magnetron.

8. my case I did not test the transformer or capacitor because they rarely go bad and the test equipment is about $150.

9. So I just bought the diode, about $10, and replaced it.

10. I also bought a magnetron for $102 and replaced it. Again look for video on UTUBE if you are unsure of what a diode and magnetron look like and how to replace them.

11. Reassemble, plug it in and test for two minutes on high with a cup of water.

After I did these things the unit worked like new. Hope this helps and good luck.

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A rather expensive repair: $112 for the two parts, plus how many hours of work? Would it not be cheaper to buy a new micro?

by ewaloumbee

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I fix microwaves for a living, they store over 4 thousand volts in the high voltage section, and if you don't know what you are doing, don't take the cover off.Yours could be one of several problems, if it programs and goes through all the motions but no heat,then you have some type of high voltage problem, that could be a bad high voltage transformer,capacitor,magnetron on rectifier.take it too a pro or have a pro come to your house.good luck

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+ like rj713 said "in complete agreement"

by oldturkey03

I have a Frigidaire Microwave and when turned on, it makes a rumbling sound and does not heat, everything else works. Do you have any idea's what it could be. I used it maybe 30 times at best. Thinking the Magnetron is the problem. Because it is a few years old, they refused to replace it, when the fist one never worked out of the box. Unbelievable

by cmb0488

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Switch contacts in the latching mechanisms can fail or become intermittent. Printed circuit boards behind touch pads can flex causing printed circuits to develop cracks over time, resulting in the same type of failures. These include no heating or ventilation fan or intermittent operation, running with door open, etc. Hard to find or fix sometimes, usually it's poor design.

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I was electrocuted when I was younger, they said I was clinicly dead for 45 min before they brought me back, and I literally did not fully wake up until the middle of the next week! The smell of burnt human flesh, and the excruciating pain should be more than enough to reason to stay away from high voltage unless you are properly trained in it. I still work with electronics and electricity but mostly low voltage projects.

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i'm a general fix it (computer and sort of general handy) guy my microwave stopped working no power no nothing i looked up on the we bthe most is $3.00 fuse i don't mind buying a $3.00 fuse if it's going to fix the 100.00 microwave otherwise that's it's far i'm gonna go otherwise i'll just buy another not worth the electrocution.

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I understand, no power at all. Check the fuse in plug (in UK we have), check the fuse in the microwave oven, placed above fan.

If find blown fuse, check appliance for short circuits.

Working with microwave oven is dangerous.

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Mine only does that after 2 am. Sound funny but microwave works day time just fine. But

In the middle of the night when my husband wants to worm up something it does not

work timer is working but doesnt turn on no heating

Weird

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That makes absolutely no sense whatsoever.

by gtaentertainment

Sounds Funny, my Microwave stopped heating, it works only when I turn on the ventilation fan. I do not understand the connection between heating and ventilation fan. Please advise if you know the answer.

by Vinod Paspuleti

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There is high voltage fuse between transformer and magnetron.

Fuse can be fitted on transformer in black tube, or next to the transformer in white tube.

Fuse required 750mA - 900mA5kV, mA depends on power of microwave oven.

First thing to check if microwave oven not warming up food.

Failed rectifier will cause to burn main fuse.

http://bargains-zone.co.uk/en/small-elec...

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Take it to professional don't attempt yourself you can get seriously injured or worse.

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Have had this happen to my microwave. What I found was the door switch is not actuating correctly. When it happens, if I pull up a little on the door, while the door is closed, it runs correctly. My micro is around 11 years old.

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I have a Bosch Serie 4 HMT75M521 Built In Microwave Oven and it only works 38 sec. then it stops, if I repet it stop at same time

What is wrong

Johansen

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Mike will be eternally grateful.
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