How To Easily Test Microwave Oven Parts! (Ultimate Guide)

[@mustangflyboy]

This is a truly comprehensive, methodical tutorial for people like myself who are comfortable working with electronics, but are unknowledgeable about testing microwave ovens. I have the top-rated, gleaming stainless steel, above-the-range GE microwave that quit heating after only three years and four months of use. Because of your video, I easily identified a shorted HV transformer. (Prior to finding your video, I located two bad components: the HV diode and magnetron. However, the oven still didn't heat. A professional electrician tested the unit, failed to find the HV transformer failure and gave up.) The Malaysian-manufactured unit is stuffed with Southeast and Far East Asian components. In sharp contrast, our 22-year-old Ohio-manufactured Tappen 1000w microwave oven continues to give top performance and trouble-free service. (I would pay the premium and buy USA, if given the choice.) Thank you for producing an outstanding series of how-to videos, which are worthy of a college-level (or, at least, a good trade school) course in electronics.

[@electronicsNmore]

Glad my video was able to help you!

[@Nyck461]

I watch the previous video and what I have to say is that this video is fantastic and "electronicsNmore" know how to make good videos about microwaves. He is very detail and able to show how to test parts to people of any level of electricity knowledge. Congrats.

[@RafaelKarosuo]

Agree with the fact that he is accurate enough, but not too wordy to confuse anybody. Very good videos indeed.

[@supot707]

this is the best teaching video, it is the best of all and wil be the best forever.

[@electronicsNmore]

Thank you! :-) Please be sure to share my channel, watch my other videos, and subscribe.

[@joefoss9249]

electronicsNmore - Thanks so much for sharing your expertise & posting this video. Using your helpful tests, I was able to rule out the magnatron, high voltage diode & transformer. The high voltage capacitor tested bad. Replaced it & my old 1982 Sharp R8320 convection microwave started right up. They don't make them dependable like that anymore. THANKS AGAIN!!

[@michaelloftus9406]

THIS IS BRILLIANT. EVEN THE THICKEST CAN FOLLOW THE DEMONSTRATION TWO THUMBS UP 22-9 2015

[@electronicsNmore]

+Michael Loftus Thank You! Be sure to watch my other microwave oven repair video as well.

[@k.g.susanthaperera1473]

Thanks for very valued information about micro oven trouble shooting ,

[@santiagoescalambre8116]

your the best!!!...I just found out the problem of my whrpool microwave after watching your demonstrations...thanks a lot...your a good man not selfish, GOD BLESS YOU AND YOUR FAMILY....

[@electronicsNmore]

Thank you! Be sure to share my channel with others and rate thumbs up.

[@brianbitney1022]

Great video. All of my components tested good but I saw sparks through the holes in my magnetron case. Knowing that couldn’t be good I replaced it and now it works. I had seen on another sight the same testing for the magnatron and they said it could test good but still have issues. I tore it apart afterwards to get the magnets and saw that the input inductor was burnt on the varnish. May be why it was sparking. But great video. I learned a lot.

[@dicanzhu8701]

Respectfully appreciate you for the information

[@runen9658]

Thank your for taking the time to make this troubleshooting video, it was helpful!

[@electronicsNmore]

Glad you enjoyed the video! I have a lot of excellent videos on my channel that cover many different subjects, so be sure to check out my extensive video playlists for other videos of interest to you, rate thumbs up, and share my channel with others. Thank You

[@DjZorlag]

Very good videos about microwave fixing! Unfortunately my oven had a high voltage (5kv 0.7A) fuse blown which you didn't address in your videos (probably many ovens don't have one), but that was easy enough to figure out myself. My symptoms were: Everything else works but oven doesn't heat. Lights, fan, even transformer hum was present. After testing every other component I was suspecting some fault inside the magnetron even though it measured 0.3 ohm with an ESR meter. DMM showed below 0.1 ohm delta reading with leads shorted compared to connected to a magnetron so it was no help in my case. I fixed mine temporarily with a 0.315A 1000v FF multimeter fuse for the next 2-4 weeks until correct size fuses arrive from china (1.1€ for 5 pcs). I know that if the fuse blows now, the arc might not close inside the fuse because of inferior voltage rating and difference in construction. But I, a cheapass student, won't have a microwave otherwise so I take the risk of causing further problems with this cheap oven. :)

[@jammgor]

This is the simplest instruction for us amateur fixers in my humble op.

[@japsr1]

It was the magnatron. Installed a new one and it works great. Thank you very much for the great videos and the help!!!!!!

[@electronicsNmore]

Good to hear! Share and rate Thumbs Up. Thanks.

[@johncipriano2852]

Excellent video, Thank you for the detailed step by step instructions and component test info! ...I will definitely share the link with others !

[@josephfolsom2030]

Excellent video. Very in depth and detailed

[@electronicsNmore]

Thanks Joe! I have many excellent videos on this channel that cover many different topics, so be sure to look over my video playlists and most importantly share. Thank you

[@Rehbz28]

Such a good video, helped me fix my microwave

[@raiderman28]

Excellent explanation of each test. You must be very good at what you do.

[@electronicsNmore]

Thank you Paul! Be sure to look over my extensive video playlists below for many other videos of interest to you, and most importantly take one minute to share a link to my channel with others on social networking sites. kzbin.infoplaylists

[@raiderman28]

Your attention to detail is awesome, except my name is Raul , not Paul. Hahahahahaha. Its ok, i get that all the time

[@electronicsNmore]

@@raiderman28 LOL. Sorry about that.

[@danherron2884]

Great great videos! I'm reviewing at work and can't wait to go home and fix my KitchenAid microwave!

[@electronicsNmore]

Good luck. Hope you fix it. :-)

[@pieterpengilly3394]

I thank you for this information . I find it absolutely well prepared and very informative .

[@electronicsNmore]

Glad you enjoyed it! I have many videos on my channel that cover a wide range of subjects, so be sure to look over my video playlists below for other videos of interest to you, and most importantly share. Thank you kzbin.infoplaylists

[@pkinkuseikh8326]

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[@JeffZhang007]

In my case it was the capacitor. Unfortunately it was the last thing I tested for I was afraid of the voltage thing. Anyway I did diode, magnetron, the little switches, those fuses and breakers first. One fo the 20A fuses was bad, replacing it bought the lights and display back, the microwave was turning but no heat. Anyway, when I finally get it off and check the capacitor, it was leaking oil and short. I just ordered one from Amazon and hopefully that's it. Thanks a lot! Will paypal some if the new caps fixes the issue.

[@vijayammula]

This is an excellent guide for enthusiasts trying DIY fixing of microwave. One question: If high voltage transformer primary tests 120 v AC on each terminal to ground, what does that mean?

[@electronicsNmore]

That means your transformer is not connected to the neutral wire allowing it to turn on. The circuit is not complete. You have to trace the wire and find out why(there may be a faulty switch or blown thermal cutoff). If you connect a 120V live / hot wire to one side of the transformer, and the other side(terminal) is not connected to the neutral wire, then you wire have 120V on each terminal. If the neutral is connected, you will have 120V on one side(power feeding in), and the other side connected to the neutral wire to complete the circuit, will be ZERO volts. Thanks For watching! Be sure to check out my video playlists.

[@husseinlodhee2357]

Hat's off...Vraiment Formidable...

[@electronicsNmore]

Heureux que vous avez aimé la vidéo

[@HongNguyen-ed1if]

Excellent for teaching

[@electronicsNmore]

Glad you think so! Thanks for watching

[@japsr1]

Thank you, I did test the capacitor and it tests normal I think at 9.37 for a 10 ohm capacitor and the terminal to body on each test infinity (followed your video). The buzzing is coming from the transformer. If I unplug the magnatron the tranformer still hums but the loud buzzing stops. Left the magnatron unplugged disconnected HV wire to the capacitor normal hum from the transformer but no buzzing. The tests of the transformer were all normal low side read .7 at 200 ohms and terminal to body was infinate at 20M ohms. High side .5 at 200 ohms and terminal to body was infinate at 20M ohms. The HV wire tested 91.2 at 200 ohms. I also tested the new diode and it was normal. I tested all the door switches, the thermo sensor, the fuse and transformers on the board all were normal. Again everything works except buzzing from the transformer and no heat, the magnatron is silent. I visually again inspected the magnatron, no cracks, sounds, etc... I also retested it and get .5 at 200 ohms and each terminal to body reads infinate at 20M ohms. Do you still think it is the magnatron?? and again THANK YOU VERY MUCH FOR THE HELP!!!

[@electronicsNmore]

If you unplugged the magnetron from the transformer, then got only a hum and no buzzing, then that would indicate the magnetron is causing the problem. You need to swap out the magnetron. (0.5 ohms) for the magnetron is higher than normal.

[@MYNICEEV]

A very informative tutorial. Many thanks.

[@fredlungu2724]

Great videos,very helpful

[@electronicsNmore]

Glad you like them! Be sure to share my channel with others. Thanks Fred

[@tiktoker_adik]

very good explanation this will help me a lot thanks

[@barry5724]

It turned out to be the door switch. There are two switches in series. The mount on one swtich was broken so the switch shorted. Thx for your help.

[@kathleenibrahim6233]

I really enjoyed your video,Thank you very much. my Q is after i found the problem in my microwave was the rectifying diode,when in stall right one mic was working but take to long than normal heating.

[@dataranger974]

Thanks for a great in depth video. Very very kelpful

[@electronicsNmore]

Glad you enjoyed my video! Be sure to check out my extensive video playlists for other great videos of interest to you, rate thumbs up, and share my channel with friends. Thanks

[@johnduff36]

Extremely Helpful Video,full of detailed information Thank You !!

[@electronicsNmore]

You're welcome! Be sure to check out my extensive video playlists for other videos of interest to you, rate thumbs up, and share my channel with friends. Thanks

[@surgingcircuits6955]

Great Video!

[@davefaddel6761]

Once again, a really fantastic video. My only query is why don't you just test the diode with your meter ?

[@electronicsNmore]

You can't test high voltage diodes using the diode test setting on a DMM. Thanks for watching!

[@JohnDVoyles]

Thanks, I will look for it.

[@tfsishuba1369]

like your videos!!! so loaded!

[@electronicsNmore]

+franse sishuba Good to hear! Be sure to rate thumbs up and share with others. Thanks

[@yesplease1000]

Microwave capacitors will usually have built-in resistors connected to each terminal so that the capacitor will discharge automatically when the oven is switched is not in use.

[@electronicsNmore]

Yes, slowly discharges with the internal 10M resistor. Thanks for watching!

[@MrUsaer]

Doug...Well I replaced the magnetron.... drum roll.................... it still buzzed. I know. Anyway, as if that is not bad enough, the magnetron that I purchased was...... well.... a used one. I really expected it to be a good one since I bought it from a very reputable seller with 100% feedback rate on ebay who only sells appliance parts. He claims the part came from a working oven and was tested. Regardless I still can not be 100% sure that it is a good one. Now I decided to buy ALL NEW PARTS including mag, generator, cap, and diode. (Diode and cap tested good, but not taking ANY chances this time!)This way I will be able to return any parts not used since they have a no question asked return policy. I will keep you posted. Thanks Paul

[@electronicsNmore]

+MrUsaer You made sure the HV transformer is not vibrating?

[@MrUsaer]

+electronicsNmore I remember that I did push on transformer with a long plastic pipe while it was running to see if that changed the noise pitch while running, and the noise level stayed the same. The loud buzz definitely sounded electrical, and not like it was physically vibrating. (I assume this is what you are talking about) I have 2 questions.... 1. .Do you know if a weak regulator can damage a magnetron OR visa versa? I only wanted to replace the bad part and not waste money on replacing parts that seem to be working ok. 2. Is there a such thing as a WEAK diode, or do they just go bad all at once like a fuse? I only ask because it seems that when buying a new regulator some online sellers seem to want to sell you a new diode as a package deal with the regulator. So if my regulator is bad, is in necessary to replace the diode too? I should have all new parts by the end of the week and will replace them one by one starting with a brand NEW magnetron... unless you suggest a certain order to start replacing the parts. I purchased a new mag, trans, cap, and diode. Much appreciation for your suggestions and help.

[@electronicsNmore]

If the HV transformer has been properly tested, as well as the HV diode and capacitor, then usually the magnetron is faulty.

[@MrUsaer]

+electronicsNmore The new parts came in last week and I replaced EVERYTHING. The cap, diode, magnetron, and transformer. Of course the buzzing stopped and it worked fine. I started pulling out the new parts and replacing with my original parts. As soon as I installed the original old transformer it started buzzing again. I tested side by side ALL of the old and new parts. The readings on both old and new parts were identical. Is there anything that I could have missed? I think you (or someone else) said that sometimes a part will test as OK, but it may not work when installed. Maybe this is one of those times. Had fun and learned a lot about my multi meter and micowaves ..... so time well spent. Look forward to any thoughts you might have on why the transformer tested ok but was still bad. Thanks again for your help!

[@electronicsNmore]

The buzzing you heard was arcing. If you left the cover off and stood back while the microwave was running in the dark, you probably could see where it was arcing.

[@dgautieri]

Very good instructions. However, can I suggest you to add a test for the transformers low voltages ? You should test if there are no short between the secondaries.

[@electronicsNmore]

The circuit board mounted transformer?

[@dgautieri]

Yes, the little ones. It could happen, sometimes, that because of a default on the board driving to a peak of current a hot point between the secondaries. This is valid not only for the microwaves. You can use the mutimeter to perform the test. In case of any doubt, you can drive direct current into each secondary with your external source and test the other secondary from its two ends and, 2nd test, one end of it to the two ends of the first one under DC. Repeat this with the second end of the secondary considered. In fact, it is an insulation test between those secondaries to perform.

[@vintagerarebaldguy4190]

awesome tutorials..thank you sir for sharing your great idea

[@PL-kz3om]

Very nice explanation👍👌

[@SCHNEIDER2862]

Outstanding video. Very detailed. Thank you for your effort. I have a situation and could use your expertise. I have a Kenmore Elite over the range microwave. My Son heated up some grub late at night and my wife came in in the morning and heard the microwave humming and could not shut it off. she pulled the plug and plugged it back in and everything was fine except it would not heat and would make a weird noise when she would try to use it. I took it apart and found that the Magnatron cooling fan shroud was melted and would not let the fan turn (ie weird noise). I cut the shroud from around the fan; put it all back together (to see if everything worked before ordering new parts) and everything works fine except it doesn't heat. My conundrum is:Should I even try to repair this? The only reason I can think of that the microwave was running when she woke up is that the filter was so clogged (didn't even know that there was a filter and has been there for 6 years caked in grease) that the system couldn't cool itself; the shroud melted, stopping the fan, which was getting a signal to cool the Magnatron. Which put it in a loop (glitch). Wouldn't even be wasting your time; but this is a very expensive microwave to replace and it's too cool. :) .Everything on the inside looks brand new and is probably the thermal switch that tripped but wanted your expert opinion on this before I started. I guess I would like to know if you have heard of "anything" like this? My problems are "never" easy. Thank you in advance for any help. Mark

[@electronicsNmore]

Mark Schneider You need to test the parts according to the video. Not much else I can suggest. I have 2 videos on this subject. If everything tests OK, then replacing the magnetron is usually a good idea even if it tests OK.

[@SCHNEIDER2862]

electronicsNmore Any good leads on where to get a good cheap Magnatron? Amazon, Ebay or a better place? thank you, Mark

[@harryhall7801]

GREAT VIEDOS! I LEARNED A LOT, THANKS!

[@electronicsNmore]

Thanks Harry!

[@NoDiggatyDANG]

4:02 LMAO!!!! HE'S GOT ONE RIGHT THERE!!! 😅😅

[@Tech-gc8tt]

Great videos! If I have parts that are bad. Where do you get said parts? Other units, or?

[@ronmartinmhg2804]

I have a Sharp microwave oven. Everything works except the digital display, including the clock of course. Any tips on the problem and how to fix it. Thanks in anticipation. I like this video. Very precise and clear.

[@electronicsNmore]

ron martin Mhg Sounds like a faulty LCD display or faulty conttol board.

[@ronmartinmhg2804]

Thanks for the advice.

[@gerrys6265]

Thank you so much! My metre doesn't go above 20M so can't do the second test on the diode, but it read 8.4 volts on the voltage test. I guess that is good enough eh? The Capacitor was the only faulty bit since the reading between the two terminals went to 1.4. No reading change on the terminals to casing. The microwave display and light comes on but as soon as I try to heat something, it instantly blows the fuse....would the bad capacitor do that? Great instructional, thanks again.

[@alfredleung3738]

Hi , you could also test the diode with a 9 volt battery since our multimeter tester cannot supply enough power to elicit a reading

[@electronicsNmore]

For a reliable test, higher voltage is best.

[@keithjacob5760]

Most interesting, may I ask ? can you not measure the voltage out of the output transformer while on to see if the transformer is working ie sending power to the magnetron ? and what would you expect the resistance to be on those same leads with a the machine off and capacitors discharged?

[@electronicsNmore]

VERY dangerous! You need a special HV probe like I made on my channel. Or you can remove it after unplugging the microwave and discharging the HV capacitor and do as shown below. Do as shown at your own risk. It's very dangerous for the average person. kzbin.info/www/bejne/jJrGn3-mo9yCY80

[@winstonclarke9221]

Do you have to start the vehicle first,or after to make your connections? To test the oven diode.

[@WesternElkHunter]

Awesome video - thank you for making it and posting it on youtube!

[@richpodlesnik7950]

Thanks for the videos. I've read your comments and I think I have a puzzle. The puzzle occurs when heating more than one batch that needs heating. The first batch heats fine. When we heat the second batch it takes longer. Everything else is fine. Please suggest any possible solutions. Thanks

[@electronicsNmore]

Sounds like the magnetron is failing. You can try testing/replacing the capacitor/diode. You may also have an issue of burned relay contacts not allowing full current to the HV transformer.

[@georgeballot4219]

Thanks SO much--- saved me a lot o money! Thanks for NO irritating bg music!! At last a guy who knows what his talking about! Geeeez! --- ther's a lot of aholes out there--- BEWARE!

[@electronicsNmore]

Glad it helped George! Be sure to rate thumbs up, consider subscribing if you like a wide range of helpful and informative videos, and look over my extensive video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Thank you kzbin.infoplaylists

[@alialywa4892]

very informative and educational thank you

[@electronicsNmore]

+Ali Alywa Glad you enjoyed the video!

[@gordhowe3128]

this has been one of the best how to i have seen thanks for taking the time to share, is there a way to test the relays on the controlboard with out taking them off?

[@jaspergustavo4922]

InstaBlaster...

[@ThePreyMantas]

Thanks for the proper, safe process. Interestingly, about half the folks DON'T test for shorts on the Mag (terminals to body) which ultimately was my issue as I was seeing continuity from terminal to body. Just received and install the new Mag and it tested out exactly as you specified .001-004 ohm across the terminals and OPEN from terminals to body and my unit is cooking again and operating quitely (comparatively speaking), it sounds like new again. I do have a few questions maybe you can answer as I haven't found anything yet on the subject: 1. can a shorted Mag be repaired? The terminal block looks clean, so it must be an internal short and 2. As far as the part # mine is an LG 2M246 050GF 1200watt and there is an additional set of letter/numbers under model #. Is the main number I need to worry about the 2M246 or are any of the other numbers important to match? Thanks again!

[@electronicsNmore]

Not worth the time repairing, you can buy a used replacement on Ebay at a low cost. Thanks for watching! Be sure to share my channel with others.

[@ThePreyMantas]

@@electronicsNmore Will do! KUTGW!

[@esar799]

So helpful; thank you. If one of my capacitor caps (the plastic) snapped, is it OK to still use the capacitor, maybe with some electrical tape holding the broken plastic in place? tia.

[@mtrltoolman]

Great video thank you very much for your useful channel

[@electronicsNmore]

toolman talal Glad you enjoy the videos. Please share my channel with others and rate thumbs up. Thank You!

[@macdaddypimpping]

Everything checked out okay on my microwave according to your guide on oven parts. But my 1st instinct was the Magnetron went bad but has 0.1 Ohm resistance which you said it is good (0.1 to 0.3 ohm). I put on heating and I can hear humming but no heat. Any suggestions? Thank you for your informative videos though.

[@electronicsNmore]

Very likely if the diode and capacitor are both good. Sometimes a magnetron can test good, but be bad. Did you measure the resistance from each terminal on the magnetron to the metal chasis? You should not get any reading. If you do, it's bad. Use a high ohms range on your DMM. Thank You For Watching!

[@macdaddypimpping]

electronicsNmore I follow your guide and I didn't get any reading for touching metal chasis and one to the terminal. If I have another magnetron from other microwave can I hook it with the one that's not heating up to test?

[@electronicsNmore]

If the size is similar(wattage), and it bolts in the exact same way, then yes. Substituting another known good one, will let you know if yours is faulty.

[@macdaddypimpping]

Magnetron doesn't have any wattage on the label. How can you tell the wattage?

[@electronicsNmore]

Go by the label on the microwave oven. 900w /1000w...etc.

[@kcgreen4702]

For diode testing, why don’t you turn your multimeter dial to the diode test position? Hard to tell, but I believe it’s the 6:00 position on your meter.

[@debrabillowitch1366]

I have watched your videos and they are helpful but I have a question. When testing the hi volt line on a GE transformer in our microwave, I get a reading of 76.5 on the high voltage side. Is that acceptable as you have mentioned 80-120 is desirable (you got 95.5). All of the other components have checked out as you mentioned and we did replace the diode but it still makes a loud humming noise and does not produce heat. The GE Profile Sensor convection microwave oven we have is 16 years old.

[@electronicsNmore]

That's fine.

[@debrabillowitch1366]

@@electronicsNmore well then the only thing left is to replace the magnetron because as you noted they can test correctly but still be defective. Your opinion?

[@igotstoknow2]

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.

[@IlkinJamalli]

Thanks for the video. I have tested all the switches, termal switches, fuse and all good. Everything is working except heating. There is no 120v on the entrance of the big transformer hence no charge on capacitor. What could be the issue?

[@basheerkhan6040]

well explained bravo love your explaination,very informative video bless you.

[@electronicsNmore]

Glad you enjoy them! Be sure to rate thumbs up and share. Thanks

[@MrUsaer]

Hey Doug.... No buzzing after following your instructions below. I am going to buy a new magnetron and hope for the best. I was curious about 2 things....... 1, When I followed your instructions by disconnecting the red HV from the transformer, would the mag be getting power from the other wire going from the capacitor to the mag? 2. Would you expect that low-end 80 ohm reading that I have on the HV secondary to gradually get lower as the oven gets older and result in less effective heating for cooking? I will post back the outcome once i receive the new mag from online purchase and plug her in. Thank you very much for your help!!!

[@electronicsNmore]

+MrUsaer You're certain the capacitor and diode are both good? If so, then try a new magnetron.

[@MrUsaer]

+electronicsNmore Yes, pretty sure. I did the cap tests per your video and did the 9v battery test for the diode....which I believe I read later that you were not a fan of.... anyway, the diode test showed full 9.3 volts one way and about 6 volts the other way as best I recall. If the mag ordered online does not work I am allowed to return to the seller. So not a big deal if it turns out to be something else. Should have it by Friday or Monday..... Will let you know... Thanks again!

[@mothanagharbe513]

thnx man you are the best⚘

[@electronicsNmore]

Glad you liked my video! Be sure to share my channel with many others, and look over my extensive video playlists below for many other videos of interest to you. Thanks kzbin.infoplaylists

[@pubdom1706]

Great Video. How do I check when my turntable motor does not have 120V input power? I test the motor with 120V source and it works but there is no power supply to my motor.

[@electronicsNmore]

Trace the wires. Could be a faulty relay.

[@geojor]

very helpful, thank you...

[@avdabke]

Thanks a lot for your video. It helped me isolate the fault to what I think is the diode. This is a Kenmore Elite , about 6 years old. My problem is that I cannot find the diode it is using. It is marked CL04-12. I had to settle on buying from eBay and I bought three of them. When I replaced one of the new diodes in the microwave I still hear a loud hum. When I disconnect the magnetron the hum reduces substantially. Everything else is working, lights timer, turntable etc. The capacitor checks out at 1 microFarad. I suspect I got cheated on the diodes. The new diodes show 15 Mega Ohms in one direction and over limit in the other. I am using a Fluke 87v DMM. What else could be wrong? The magnetron also checks out as per the tests.

[@markallen1060]

Replacing the capacitor did the trick. It is the slightly lower 2100 VAC but it works. Now the lamp has died. That should be a piece of cake to fix. Thanks again for the video and suggestions. Mark

[@Edmorbus]

Thanks for sharing

[@babythomas2902]

goodl talk. But Blue letters are difficult to read where there is no enough light.l think white letterട are So good insted of blue letterടThanks for your great work-

[@electronicsNmore]

Yes. I agree. I switched to a different method 5 years ago. Thanks for watching!

[@Capricornarr]

hey there, i have the analog electrical meter so could you pls tell me what position/symbol/mark to select to check the capacitor after you do the ohms check. ta

[@electronicsNmore]

+Capricornarr If your meter is inexpensive and does not have a "F" setting meaning Farads(capacitance), then you are out of luck. You will have to rely on the resistance test.

[@Capricornarr]

+electronicsNmore Thanks for your quick response, I only have an analog electric meter which is clearly no good in this situation. Could you please suggest any good digital multi meter that would do all these jobs and I would be able to do all these checks? cheers mate.

[@electronicsNmore]

Vichy VC99 on Ebay.

[@vinneygambino5596]

Hello, I have a dead microwave. The light works when you open the door, but no display nor do any buttons work, fuse is good. I have narrowed it down to the PC Transformer according to your very interesting and informative videos. How do you remove it from the board for testing? Thank you.

[@Sturmmann20hz]

Can the PCB transformer test be done while still attached to the board? Or do I need to de-solder the transformer?

[@kathleenlehane6652]

Hi what a wealth of info. My Maytag has no power, no display, nothing, fuses are good. Suspect your suggestion that the transformer is the culprit, so instead of checking it out I got a price for one - cheaper to buy new micro wave so I will not bother testing. Thank you sharing all your info

[@electronicsNmore]

Microwave ovens that don't power up at all, are usually the easiest to repair! Just connect one leg of your DMM to the microwave metal chasis using the 250VAC setting, and the other you will probe the hot wire all the way to the circuit board to see where the power stops. The problem could be a thermal cutoff, or the PC mounted transformer which is faulty. I would take the time to test it. Thanks For Watching

[@kathleenlehane6652]

electronicsNmore I cannot Id part you are referring to - no listing for pc mounted transformer and I have nothing that looks like this, although in looking deeper - right next to fuses on pc board their are wires that run to power cord that look to be burned. White is burned - black looks okay. Can this be replaced and is it possible this could have happened from a power surge. Would have sent pic but ...........

[@electronicsNmore]

If you see something burned, repair it.

[@sgian]

This is an excellent tutorial, very clear to understand. I have a related question: you indicate to use a 18k ohms 5-10w ceramic resistor to discharge the capacitor; may I use a film resistor of the same ratings? Thank you.

[@electronicsNmore]

Any resistor, just as long as the wattage/resistance value is close.

[@javedkarim3324]

Thank you sir very nice explain

[@sarahbillittier9561]

Thanks for uploading this was so helpful! While testing the transformer, the resistance between the single high voltage wire and the body of the core did not change the reading from OL. Does this mean the transformer is broken?

[@electronicsNmore]

Place the digital meter on a low ohms range(up to 200 ohms or 1k ohm) You should get a reading. Be sure to scrape the transformer core in the area you test from. There is an enamel coating which must be removed to expose bare metal prior to testing. Thanks for watching. Be sure to rate Thumbs Up, and share my channel with others.

[@sarahbillittier9561]

electronicsNmore That did the trick! It was reading 154 ohms. Thanks :)

[@leonwilcox2663]

Hi how do you check the thermal switches when you removes the wires sould you have resistance or should they be open when good?

[@randallzurrin2404]

Awesome video, still have problems. Micro would buzz, but would not heat cup of water. Power setting button did not work, everything else did. Replaced Diode, set power to 2, fired it up, and fuse blew. Replaced fuse, turntable, fan etc. ran with transformer unhooked, all was O.K. until Transformer was connected, fuse blew again. All test readings on mag, transformer and cap are same as yours. Ideas? Also, can I wire a 20 amp household breaker in-line to test? Blowing ceramic fuses is getting expensive!.

[@electronicsNmore]

Fuse usually blows if a door switch is misaligned or faulty, the cap is faulty, or the magnetron is shorted. Thanks for watching!

[@marcelchabre4119]

Appreciate the videos, tremendous help. Lights would come on but microwave did not work. Replaced switch a d a thermocouple. Now everything works but exhaust fan turns on as sonn as I plug it in? I can switch speeds but won't turn off? Hope you can advise. Thank you in advance.

[@electronicsNmore]

Bad thermostat(heat sensor). Make sure you installed the correct parts, and wired them correctly.

[@dallen957]

Awesome video. Easy to follow steps. I have a GE countertop microwave that does not heat. Control panel functions fine. Fan runs. Light in oven comes on. Do not hear the sound of the magnetron kicking in. Followed your steps; i.e., door switches tested OK; relay on PCM registers 120VAC and then goes to zero when start is pressed. Magnetron checked Ok for ohms, however, the fins rattled when shaking the mag. Was able to push them together and eliminate the rattle. HV transformer, capacitor and diode all checked OK. I think it must be a faulty mag but is their any additional tests I can do before springing for a new mag?

[@MrUsaer]

Hey Mike.... Great video! I'm looking for some advise before I can even think about trashing this older but expensive 1650 watt GE built-in oven. I get the annoying buzzing BUT the oven does still heat at what seems to be it's normal heat rate. Here is what I did so far..... 1.I did ALL the magnetron tests in your video. All tests were normal EXCEPT when testing across the 2 terminal plug on a 250 ohm setting, I get a reading of point five (.5) This is also the exact same reading I get when I simply touch only the 2 probes together. Does this indicate that there is a short since .5 is my starting resistance due to the resistance of the meter and probes itself? IF yes, I do not see how the oven would still be warming! I also tried 2 other cheaper meters and each said resistance was one point zero. (1.0) Again, both meters tested at 1.0 when only touching the probes together. (Again I assume this is because of the normal resistance to the meter wire and probe itself and the meter just not being 100 percent calculated) Do you think I have a full short in the mag based on the above reading? 2. Next, I ran ALL of your TRANSFORMER test. All were ok EXCEPT on the high power wire test I got a reading of 79.5 olm on my good meter and 80 and 79.5 on the other two cheapo meters that I have. I believe that you said between 80 and 140 or so was most common I am at the extreme low end or below....so could that be causing my BUZZZZ? 3. I also tested the cap and diode test. Both test were good. (did a test using a 9v battery for the diode) Both of those test we ok as I expected. 4. I removed the mag. Shook it. No noise. I also carefully looked for cracks and any burning on the head. The silver thingee that surrounds the head of the mag was nice and shiny silver but there is some kind of metal thing inside of that shiny silver part that was black.... but i assume that is normal....right? 5. I can not tell if the buzzz sound comes from the mag or transformer. I disconnected the 2-wire terminal plug that goes into the rear of the mag. When I turned the oven on, i did not hear any buzzing, but of course there was no heat :) I would guess that might not tell me anything since I assume that pulling out the mag might also stop the buzzing even if the transformer was bad and causing the mag to buzzz. Any thoughts or questions would be really appreciated Thanks!

[@electronicsNmore]

+MrUsaer Hi there. I'm Doug. :-) 80 ohms on the HV secondary is fine. You can unplug the unit, discharge the capacitor, then unplug the red HV wire from the transformer leading to the capacitor and leave it sticking out and away from the metal chassis. Plug in the oven, stand away from the open areas(danger areas) of the oven, and TOUCH NOTHING except for the control pad. Enter 10 seconds and press start. See if the buzzing sound is gone while the oven is running, if it is, then you likely have a faulty magnetron even though it tests ok. Unplug the oven, discharge the cap again to be safe, then you can touch things.

[@juanabreu5127]

It seems to me that MrUsears is having an issue with the mica lid that covers the openning of the waveguide in the oven cavity. Thanks for your video.

[@TheRainHarvester]

@@juanabreu5127 What can go wrong with those mica covers? Just curious.

[@csabamogyorosi3362]

Thanks for the video, it is the most informative guide I have seen so far. Excellent step by step instructions. I have one question. I am checking the step at 14:15 and instead of getting 95 ohm I got no measured value. Is there a way to further check the transformer? Thank you

[@electronicsNmore]

No reading for the high voltage winding means a faulty transformer, or you failed to scrape away the clear coating on the transformer before touching the probe to the core.

[@enufots4621]

Is it mandatory that I take one wire off the switch before I do the continuity test? Would i get wrong reading if i left both wires attached to the switch terminals?

[@electronicsNmore]

Removing one wire ensures reliable testing.

[@bonniebole]

Thanks so much for this tutorial and forum. Defy Convention Microwave oven DM0357. Just went dead. Perhaps overheated. I don't know. Keypad dead. Should I replace capacitor first, or the keypad? Or, is it possible the keypad alone needs replacing. Multimeter testing showed components are ok. Have to guess if capacitor must be replaced and/or keypad.

[@boybravo689]

Canl you make a video repairing a turbo broiler including a circuit diagram tnx

[@brunadelise6043]

Turntable doesn’t turn on a GE Microwave model JVM1870SK04. I hope you can help. I’m a handyman in my community and I’m trying to help senior citizen with her microwave problem. I checked the motor and I had no continuity. I also checked the motor input connection and I had 21VAC showing. The keypad turntable control was also working by verifying that it was turning the voltage to the motor ON and OFF. I tested the old motor and definitively confirmed the motor was bad by testing it with an external power supply at 21VAC. Convinced that the problem was with the motor, I ordered a new one. To my amazement the new motor didn’t work. I tested the motor with the external power supply and it checked OK. I have 21VAC power at the motor input. Motor OK. I’m stumped on the possible problem. I could order a control panel but I don’t want her to buy parts unnecessarily. Can you help with this problem?

[@electronicsNmore]

+Bruna Delise 21v? The motor operates using 120V. You need to connect 120VAC to the turntable motor and see if it starts turning, if it does, you must trace the wires back to find out why power is not being supplied. Thanks

[@lucasbretels]

One measuring of the low voltage coils (transformer) to the body is enough, (the coil itselves is low impedanced as measured before)

[@electronicsNmore]

Not true. You can have an open primary or HV secondary winding.

[@carlbigras5284]

Great video. I was able to test all of my microwave's component and all have resistance reading like you mentioned. I did more tests, I used an energy meter to measure the wattage when in use. Plugged in, 2 watts. At power start, 38 watts (light, fan, turntable) When the magnetron kicks in, 400 watts. (Instead of 1200 W) Same, but with magnetron unplugged, 325 watts. (I think it's for the power transformer) I did buy a new capacitor & diode, but still doesn't work. Next step is to replace the magnetron. Any thoughts? Thanks very much. Carl

[@electronicsNmore]

Can you hear a hum when the microwave turns on? Or does it run with the light on, fan on, and turn table only? If you swapped out the cap and diode, and you are getting 120V to the primary side of the transformer(DO NOT go anywhere near the HV red secondary wires!), then the magnetron is likely faulty even though it tests ok.

[@carlbigras5284]

electronicsNmore Yes it does hum and there's power to the transformer. Just wanted to make sure it was the magnetron. A GE magnetron WB27X10305 is $250 - $280 in Canada. Thanks for your help.

[@electronicsNmore]

WOW. What a rip off. I have 2 laying around my house. Cheaper to buy a new microwave.

[@carlbigras5284]

Yes, it was an expensive model that matched the oven and GE doesn't make anymore. That's why I'm thinking of ordering it from here; www.appliancepartspros.com/ge-magnetron-wb27x10305-ap2026205.html By the time I add shipping, customs and currency exchange rate, It'll be about $160 Thanks, Carl

[@mbhang834]

Well, thank you for your videos. I tried to repair my Sanyo EM-V3405SW microwave (intermittent flickering appliance light when door was opened or during operation and pitch change in magnetron during flicker). I was able to trace it to a relay, which I replaced (confirmed that it was relay by shorting the high voltage side of relay. I ordered the relay, replaced it - microwave is running fine - but display is blank. Is there some video you have on testing LCD display operation ? I will admit, I had disconnected the front touch pad ribbon that goes into control panel, when I was testing relay operation. Problem is I have no schematic diagram of the control board and have no idea how the display gets lit.

[@sureshlingabathina]

excellent

[@habibgill7865]

Thanks for knowledgeful and helpful video. I need your assistance to resolve issue of burning fuse when microwave put in operation. checks on hv transformer, capacitor & diode found good. Resistance on PCB on L and N terminal found 1424 ohms which seems not normal. What may be cause please guide. Thanks

[@electronicsNmore]

I only upload well explained/helpful videos and answer simple questions. I don't troubleshoot for viewers. I already spend way too much of my free time helping people, and get very little in return. This channel is underfunded. Watch my other microwave oven repair video below for more help. Thanks kzbin.info/www/bejne/qmLXlZ1phNOfjrc

[@dragon6]

Can you please make a video of the scenarios in which the fuse in a microwave blows off? Thanks.

[@electronicsNmore]

Usually a faulty/misaligned door switch or faulty capacitor.

[@dragon6]

thank you :D

[@japsr1]

I'm a fan! , but I have a puzzling problem, I have tested as you've instructed and I found a faulty high voltage diode and a faulty micro switch in the door (both parts were replaced), but the microwave continues not to heat. All other parts tested within normal range. the display panel works fine. I thought it maybe the magnatron as on testing I'm getting .5 ohms the other test is normal. Any help you can provide me would be great! or I will succumb to defeat and go out and buy another one (if only to get my wife to stop yelling at me to buy another)! Thank you!!!

[@electronicsNmore]

If the large transformer is being supplied 120V on the primary side from the circuit board relay, then I'd say the magnetron is bad.

[@japsr1]

Thanks for responding And yes the transformer is getting 120 volts so I will try a new magnatron and see if that resolves it and again thanks for the help!!!!

[@markallen1060]

I will have to watch the video again. Based on watching and replaying sections, I think my problem is the capacitor or the diode. I have a Sharp R-4A77 and it has 3 microswitches to the door. The instant I try to heat, it blows the fuse but the clock display is fine until I try to heat (I'll remove the good fuse shortly). I checked the operation of the 3 door micro switches with wiring pretty much removed (removed from wire harness), 2 NO and 1 NC, and they appear to function appropriately. What I find odd is the 1 NC when back in the wire harness has continuity when the microwave door is open or closed, but again, operates appropriately when removed from the wire harness. Sound plausible to you? So I believe you indicate if I am blowing fuses, it is likely the diode or the capacitor, correct? I am a bit leery on testing those but perhaps I will gain more confidence if I get the resistor you mention to discharge the capacitor. I would appreciate your thoughts as I hate to send the microwave to the land fill if repairable.

[@electronicsNmore]

Mark Allen You need to test the capacitor and diode.

[@CooLangOat3626]

FYI is easy to follow ... My oven is not working ... I will follow this simple test only problem is I dont have a DVM... Maybe I can use 9volt battery connected to lamp as tester... Any good? Or there is a caution I needed to think like damaging a component? 😳😨🙏

[@mudassar34]

great video but i think you missed the relay, i will try door switches in the morning but i am close to giving up, putting a new magnatron wasnt a good idea in the end a new micro wd have been better

[@ErikMiddeldorp]

my multimeters already read 0.2-0.3 Ohms when the leads are touched together and I get the same reading when testing the magnetron and transformer secondary winding, so I don't know if one or the other is bad.

[@electronicsNmore]

Deduct the reading from the measurement you take.

[@ErikMiddeldorp]

@@electronicsNmore I think my multimeters aren't accurate enough to read that low ohms, it was fluctuating between 0.2 and 0.3 ohms both while doing a reading or while just having the leads connected. I saw another video kzbin.info/www/bejne/rnuwoKWof9-gbMU which helped me confirm the transformer seems good. The capacitor and diode also seem ok, so I think it has to be the magnetron.

[@theoelectricalengineering9234]

If the high voltage diode is not reading with the 20m ohms is that means that is bad