Checking and Replacing Magnetron in a Microwave. ( Runs but no heat ) 

Jim, The reason the Tip of the Magnatron (antenna) is discolored is that the Magnatron gets extremely hot hence the fan and aluminium cooling fins within the Magnatron. The discoloration is due to the heat and is nothing to worry about within a week a new one will look just the same. Biggest tip for all users is to make sure the cooling intake to the fan is clean. Magnatron magnets X2 will crack due to heat and operating effiency drops dramaticly. ALSO REMEMBER TO ALL PEOPLE......THE CAPACITATORS IN THE MICROWAVE DO STAY CHARGED THE CHARGE CAN AND OR WILL KILL. DISCHARGE BEFORE YOU DO ANYTHING> Graeme

I have watched a lot of videos. I tested everything and still no heat. THEN I FOUND OUT THE MAGNETRON TIP SHOULD BE SILVER WATCHING THIS VIDEO !!! you are the only guy that mentioned this !!! i checked every component countless times !! FINALLLY AN ANSWER ! THANK YOU JIM !!

Just wanted to say thanks. I had 120 volts into the transformer but no heat. Everything tested good with a voltmeter. But the tip on the magnitron. It was driving me nuts then I viewed your video and changed it. It worked great. Thanks again!

Very informative and simple instructions, Thank you!!!

Thank you. Sometimes tough to see ,with all these unforgiving parts, if it is worth fixing! Gotta start somewhere!! Thank you, a lot of hours just to get here, thank you!

Jim I want to thank you for the comment about the tip being brown. I also had the same problem and after checking all components, transformer, power diode, capacitor door inter locks and megatron all checked good. Many videos tell you if megatron is 1 to 2 ohms and not shorted it is good. This is not a true statement. I also did one other step by checking amp draw and my megatron was pulling vertically no amp's. After replacing new one which by the way showed exactly the same ohms but was pulling close to 15 amp's. Great info on the tip.

Thank you for the video as I have been searching for the answer as well - changed the transformer (was bad), a relay that had a burned connector to the transformer primary line, and everything else checked out fine. The capacitor, diode, the door micro-switches - all good! I finally ordered a magnetron and keeping my fingers crossed. This is a 4 year old video, but just wanted to appreciate it since it added more hope in this interesting journey! Best wishes if you read this comment!

Good call on the discolouration. This is an educational moment for US all. M.J.😊

Very informative and simple instructions

Powerful information!!

Thank you so much for this video

This video was key to repairing my GE microwave that seems to be built by LG. Magnetron passed multimeter test, but the antenna was discolored. New magnetron antenna was silver, installed it and viola! Good as new.

I know this is old but I’m changing my tube now. In 30 years of mw repairs I may have only had two that checked bad with a multi meter. Honestly it’s process of elimination. Only four parts make a microwave and the other three are either good or bad on a meter. Mag tubes get hot so the discoloration isn’t 100 percent accurate. Mag tubes start moding internally. It can also be checked by seeing if an amp meter occilates rather than remain steady between 9 to 12 amps. Diodes generally short and or crack and are obvious and capacitors can be checked for a short to ground or the blip test. Transformers seldom fail so if a microwave doesn’t heat the most likely cause if the transformer has power is: Diode Capacitor Magnetron Tube Transformer

Thanks a lot.. your video helped me to save a good money ❤

Thank you for the video

So in your earlier video - you showed that the Magnetron checked out good ??? Ive also seen other videos that showed how to test like you did. I replaced my Magnetron several months ago and all was well. Recently my microwave stopped heating again, so I blindly replaced the capacitor and diode thinking that would do it - NO heat.. went through and did all the checks this time and all switches are good, fuses etc . any idea if my Magnetron could have went out that quick ? Also you never followed up on your Transformer check?

Hi Jim, what is the significant of silver colour on the tip of the magnetron, I have a working Microwave whose metal compartment where food is cooked had rotten away through rust and corrosion, so a friend gave me his faulty good condition Microwave whose Magnetron has packed up, I then swapped my working Magnetron into his after making a few mods to fit it as the mounts were different, I noticed that the metal silver tip of my working magnetron had burned on one edge making a hole on its edge as well as the center holethrough which the waves get emitted, I covered the small hole that had burned through on the tips edge with a self adhesive copper tape and allowed it to run, apart from some minor noise the microwave is now working, heating water, I cooked a medium size (roughly 3" ) jacket potato on full power and it cooked it perfectly, I wanted to make sure the magnetron's tip I covered in copper tape was still intact, stayed in place, and to see how hot it got after 5 minutes of cooking, so I immediately unplugged from the power socket, opened all screws and took the cover off, discharged the capacitor terminals to earth, no sparks were seen, then I touched the magnetron and it was pretty hot to touch, took it out to check the silver tip which is now covered in copper tape, it was still intact but its colour had changed from copper redish/brown colour to semi Gold colour, now I am wondering if microwaves have turned copper into Gold, would I get any credit for this? I have now managed to prise off the silver tip from the bad magnetron , I used a pipe wrench to grip it and rotate it back and forth, it came lose, and inside was a copper tube whose end had been squashed tight to seal the end, and this silver cap fits over it , so I pushed tight this silver cap on top of the good working magnetron, all seems fine now, even that minute noise has disappeared. All working good, cooked jacket potato in 5 min.

Thanks Jim.

Ty for the video....I had the same issue thinking mine was not bad...checked it with my meter and like u, mine checked out fine. My tip was still nice and silver so huh...I'm sorry to say I did watch another video and he recommended to physically check the magnets...well by golly one if not both had a crack in it...I have not replaced with new one yet but I bet thats it...thanks.

Hmmmm, I was going nuts checking all the parts the different youtube videos recommended. All looked good...magnetron and all. I also assumed it was the magnetron but my multimeter test showed good as yours did. I'd hate to spend all that money on a magnetron only to find out that wasn't the issue. You took the chance and it worked out. I'm going to give it a try. It that's not it then I'll have a spare magnetron. Thanks for video.

Hi Jim, I found this video extremely valuable. One question I have is, what type of screwdriver are you using? I knew about magnetic ones, but I noticed you were rotating your wrist without letting go of the handle, so it must be some feature that lets it go only in one direction? I didn't know those exist!

Good one thanks

Thank you Jim for your video. I have a Logik macrowave. It stopped heating and when I checked, the magnetron was missing. The worse part is I don't know the type which was there and I intend to replace it. Which type do you think can be compatible?

Make sure those screw are tight, I have noticed in the newer models the mag has safety hangers and tabs to prevent it from coming loose and falling out.

Good man

Good

Would you happen to know how to disconnect the capacitor from that particular unit? I’ve got mine apart I’ve got the only screw that’s on the back of the microwave on on the outside that I thought is holding onto the capacitor but it’s not budging.

Thank you nice video and info. Mr. Jim please tell me that CAN WE REPLACE BAD MAGNETRON WITH GOOD ONE OF ANY MICROWAVE OVEN ???

Hi. Thanks for the video. I just have one question. My microwave turns on andi hear the humming but the turntable is not turning and of course the food is not getting hot. What can be the problem?

hello mr jim mc laren pls advice me what to be done of my microwave oven, the problem is power is on but the unit is not working at all ,despite of touch push button being press. this is what ive done, checking and inspectio with my digital multi tester, fuses, magnetron, diode, capacitors, transformer, and the micro switch in the door contact, all the inspection and testing being done but the problem is still exist, by checking the main components are base of what I viewed from tutorials in u tube. please help.

I have the same mag 2M246, and a 2M248 do you think they will interchange, both are the same physically.

Good, sir Can the DEFY SMO 343 work well/ not, with any type of magnetron.? Kindly advise on this matter.? May I replace the magnetron with any brand and similar specs

I had the same issue. The magnetron checked out okay via multimeter, but it was indeed bad.

you should check the high voltage diode too

lloyd mitchell says excelent .you work like me i really like this video

One of the most common failures in a magnetron is that one or both of the circular magnets on it will have a crack in it. An ohm meter will not show this. You can often see the crack. I don't believe the color of the tip has any bearing on whether the magnetron is good or not. It will change color with normal oxidation and will not affect its operation. Out of two microwave repairs I've done recently, both had a cracked magnet. Probably caused by heat. Check that the cooling fan to the magnetron is clean and unobstructed.

What setting on the multimeter do you use to check the magnetron? 20o, 2000, 20K, 200K or 200M ?

Is it possible to check the magnetron by simply taking off the upper grill on the microwave oven and using the meter? A tech came and that's what he did and determined it needed a new magnetron, capacitor and diode.

there is small cotinuity which is bad, thanks for that

So checking the old and the new magnetron with the multimeter gave the same result, meaning that until you change it you are not sure. I don't think the color it is a sure thing either: The color does not change instantly, 5 days ago when it was working probably had the same color

Whatever the color of the magnetron antenna, mine had a big hole melted in the side. I expect that means the magnetron is bad. It is definitely worth checking the antenna on a device that yet tests good on the meter. Many, many thanks. The replacement costs $268. We wlll probably buy a new microwave.

I have a 2004 gold star which is LG microwave. A friend of mine who works on microwaves was replacing the magnetron but, he never came back. He has already installed it but did not hook up the connectors. Is there a certain way the wire connectors have to be hooked up to the magnetron and, if there is, is there a video that shows this? Nobody knows what happened to him.

I doubt even a half percent of the viewers have any idea about the specifics of “discharging a capacitor” - “just get some insulated pliers and stick em in here” doesn’t cut it; I’ve shorted out far too many things in my life to take such a casual approach… I mean…c’mon!

Would a bad magnetron cause the microwave to act as if it's not even plugged? Mine is completely dead and the main fuse checks out fine with the ohmmeter. Any ideas?

Did your microwave start getting louder making a humming vibrating noise before it died. I suspect the magnetron is starting to go in mine.

What is the cost of magenstron?

So what happens exactly. Oxide layer forms or silver explodes off?

My microwave is heating but very low. The quantity of water which was taking 1 munute earlier not the same quantity of water is taking 3 minutes to same temperature. Is it time to replace magnetron or is there some thing else? Please suggest.

Don't use the number on the label inside the door of an LG. That's the part number for the label! I did find it that way by back cross-referencing. The right number is on the label on the back. :)

That is identical to my GE microwave

I would check first the high and low voltage on the magnetron. If I find high and low voltage present then it is sure the magnetron is dead.(consider that, it is a shorter way to find the problem)

What difference would the Multimeter test do if it didn't show any difference between. The new and old one?

If magnetron bad you should read short between terminals or short with casing

My magnetron had 0 resistance, connector was burnt. Cheapest used magnetron was 20 (smaller one from different model) I bought used microwave for $20 on the same day. Check craigslist first before you spend a few hours diagnosing/learning. New magnetron is definitely same price or more expensive than same type used microwave. My old microwave, I was trying to repair, was rusty, ugly and turn table didn't work for 15 years! Good luck, guys! BTW, magnetrons die if there is no food inside

Thanks for this video... Please, how do you figure which megatron to buy. I fixed mine and i noticed that the guy that fixed it used a megatron of a smaller microwave instead of replacing the same old one. i am using LG MODEL: MS3949CS /00 230V ~ 50Hz MAX.1450W 1450 2450MHz 1000W the details are according to the sticker on my MICROWAVE

Thanks for the video. I will never purchase another LG product. My two year old, $600 dollar microwave just bit the dust. Called for warranty, magnatron has a 10 year warranty. But the labor is $240.00 for the tech to replace it. I will forget the warranty BS and purchase the part and do it myself.

Do you need the same magnetron model?

How do you discharge a capacitor

Sir is there any way to find the polarity of an magnetron

How much did the magnetron cost?

what happens if i install a 2m246 magnetron instead of a 2M226 one?

Wish I had seen this video first. Have gone thru my whole microwave...all parts testing good, except the transformer...it was shorted and blowing the internal fuse. So, I got a new/used transformer that tests good with 102 ohm running thru coil. I installed it, microwave runs now without blowing fuse, but still loud hum and no heat. Bought a new capacitor...still no heat. Now, I see this video. Oh well. I dont think the wife is going to let me spend any more money on this micro. But, I am guessing either, that the magnetron pulled too much current when it quit and shorted the transformer, or, lightning ran thru the microwave. All I know, is everything else on the microwave works....fans, lights, turn table....just, no heat.😒

How much is a new magnetron in pounds uk

How do you discharge it?

I replaced the magnetron and the diode and the capacitor. It’s still making the buzzing noise and not heating. What else could it be?

Check continuity with multi meter.

We’re do you buy a new magnetron

I think you bought some bad part or you don't check well! Ajajajaja

What was the issue

I changed out the Magnetron bit still no heat 😢

my magnetron keeps burning out, what caused it?

Mine is measuring 5 ohms between connectors, is that normal? Microwaves not heating

A Ha! You said "As long as you don't get all zeros". I know in testing a magnetron there should be less than 1oHm between the contacts. But what I there's absolutely NO reading at all?

My microwave works fine if you don't put it in for more than 2 minutes if you put something in for over 2 minutes it only makes it look warm why is that

Is it true that a disconnected magnetron holds a huge amount of power. Is it safe for me to try and change the bulb myself ? I am not a pro.

⚡Will I get electrocuted? My sister is freaking me out. So I just have to discharge the capacitor with insulated plyers? ⚡⚡ I have the new part ready to go. HELP!! 😳

Cody of a magnetron

I've got a Anko 34 litre microwave made in China it had very little use, it's just less than 2 years old and it's magnetron went, it will probably end up in landfill, ill never buy Chinese again.

appliance.academy

Did your microwave start getting louder making a humming vibrating noise before it died. I suspect the magnetron is starting to go in mine.