How to Test a Microwave Oven High-Voltage Rectifier 

Best answer to diagnoses I've seen Thank You Sincerely. Very clear

easy to follow instructions, clear & concise. Nicely done!

Nice - Thx. Love the outtro. Additional leads are not needed, just connect meter leads to diode and battery, then other diode lead to battery.

"Junk voltage" could be confusing for someone if they only heard or read the term. But I SHOW in the video an example of what junk voltage looks like, which imparts an intuitive and pragmatic understanding to "the layman."

Am I right by saying the faulty which read 9 volt both ways is an open circuit diode? Thank you 🇬🇧

So because the diode read 9volts in both directions the diode is bad? Because it didn't drop. You example was good, but I had trouble following what makes it bad.

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

Nice and simple explanation. Wish you were my tutor at high school.

I use my insulation tester on the 240volt it has a closed circuit one way and a open circuit the other. A bit quicker?

This is a great question because it brings out another failure mode of the PN junction inside these rectifiers. In the the first diode that reads 9v in both direction, the PN junction has failed short. In the second diode, where you're reading 2.5 v in both directions, the PN junction has failed "quasi-open"; in other words, it's not a true open but neither is it acting like a PN junction anymore. So it would be replaced as well.

so the bad diode is shorted.What if opened? Be zero or other voltage if partially open.Many thanks very helpfull cheers to all

Can you send me a wiring diagram on that connection from battery to the H.V Diode thanks.

Thanks for the example. My microwave works but doesn't heat. Should I check the rectifier or do you think it is a different problem. I checked the fuse that looks like a cap, tested the capacitor and the white fuses and all those seem to be fine. It worked fine last night then this morning would not heat. Any suggestions? Thank you in advance.

Thanks for very valued information Keep going All the best good luck

What the reason of continuous dropping of voltage when using 12 volts dc coming from ac adapter

Thanks for watching, Pete!

Sorry can I ask about a ERROR H51 of Toshiba Oven microwave ( low - voltage), I have a oven microwave toshiba ER GD500, it show the error H51, but I can not ask anyone to fix it in vietnam. Can you explain how to fix it. Thank you

What if with a known good battery the diode drops the voltage less than 6 volts. What if it drops it to 2 volts, is the diode bad?

What if mine is reading closed. It beeps when I put the leads on it

I have a no heat in a whirlpool microwave WMH31017AB0 all 3 door switches test ok the Diode test ok High Voltage Capacitor is not shorted to the case or each term. it is a 10meg and shows 0 when i test ressistance is the Cap bad ?

I have removed the diodes from my microware to perform this test. One diode reads the full 9v with the probes in either direction. The other diode reads a drop of about 2.5v which I think is ok but it reads the same even if I switch the probes. Is this faulty? Excellent video by the way. You may have just helped me save my £250 microwave for £25 replacement diodes and an 8A ceramic fuse.

i have a microwave oven that it works...but cant heat the food,i thought it was the fuse but not is ok....maybe the hv diode is the problem??? plz help?

Thanks for the video. This clearly shows how to test it. Thank you.

k i use ditec charger from motor to a 12v baterry using these diode w .d .o. geting to hot please help

I'm trying to repair a 6 year old GE microwave that stopped heating and makes sort of a buzzing noise. I'm starting out by replacing the diode since it is the easiest/cheapest fix and I don't have testing equipment. The existing diode appears and smells fine (no burnt smell). Is it likely for a diode to fail while still appearing good with no burning smell?

I was ready to buy an expensive multimeter that would read up to 200M ressistance olms but your 9 Volt battery test worked fine. My reading was 5.7 on a new battery. i suspected as much since micorwave heats food fine....but BUZZZZZ is driving me nuts. Tested mag and transformer.... both are borderline, but Im betting mag is bad since buzzing stops when i disconnect it. Thanks for your cool video!

I have never had any 'wild' readings like that--maybe you have an oxidation problem causing bad contact. I use homemade razer sharp and high spring tension (because of the grease-like mess) alligator clips. The readings could be so much clearer. Thanks for the video.

Good testing sir, thank you 💐🌼🌻🌺🌹

Thanks

I tested an HVR 1X 3 diode from a GE microwave and a good 9V battery. One side test shows a voltage of about +5 and the other side (reverse) shows -5 and then slowly drops. Does it mean the diode is good or bad?

Hi, great demo. But the term "rectifier" is used incorrectly, this is a diode you are checking. A rectifier is an assembly of four diodes and is used to create DC from an AC sinusoidal waveform.

great video, very well explained, i performed the same test and i got 3Vacross the diode which is a significantly higher drop than what you produced, wonder if its bad ?

Excellent

Could be the HV diode. Test it the way I show you in the video. If you need more detailed help, start a new topic in the Kitchen Forum at Appliantology.

Good idea,thanks

Nice video

Thanks for your video, Learn a lot

Sir, i have some issues with my microwave oven. I have replaced the busted fuse with the same rating as with the old one but for some reason, the new one was also blown up. When I have replaced it and plugged the microwave, everything goes fine. But when I started cooking, the microwave will start to blow the fuse up.

its showing 9.3v and -9.3v for fwd and reverse

Good video my friend!!!!!

Thanks for watching! Please share with your friends. :)

Samsung microwave... doesn't heat ,checked the Door switches and they are good. what and how do I check next? I ran the oven by mistake with out any food in it for a couple of minutes ( I know my bad) model is smh1713s

Why don't you post a RU-vid video reply to this video so we can see what you're using?

OEM vs Universal?

could you just use a dc power supply instead of using a 9v battery???

Thanks My diode is good.

For the time you spent making this, it would actually be a really helpful video if you showed all of the connections with your wires between the multimeter, to the gator clips to the battery to the diode. But instead, half of it was off screen.

Meter is not well sick

Confusing to the layman. "Junk" voltage is a figure of speech which could confuse someone.

Kind of good video. The drop voltage is 15 volt for many high voltage diode, so a 9 volt battery would not work. The bad diode can be short circuit (measure 0 volt, and a standard ohmeter would also detect a few ohm) or open circuit (standard ohmeter can not test this, neither in ohm mode nor diode mode). The good diode will not conduct in one direction, and conduct only when voltage is above the threshold. But, not illustrated in that video, you need a resistor to limit the current to the diode. In this video, the hope is that a 9 volt battery is too weak to damage the diode. It is ok for microwave oven diode as they easily work with 1 amp continuous, and many amps pulsed. If you are testing a high voltage diode for CRT, air filter/ozone generator, laser printer, etc that 9 volt battery could destroy the diode. Not wise! A resistor is cheap... often free! Use it wisely!

Thanks