#TECHTALK

Troubleshooting a microwave

[@trinityappliancerepair1344]

Great instruction Richard

[@deemon3611]

Great explanation!!!

[@vtech2281]

This was good

[@lemonman77able]

Indeed!

[@mostlikelywedoitservices6926]

Question. With over range HD microwaves with ducting. I tell them to buy a new one. By the time I drop it. Repair it and reinstall it. It will be better to just go buy a new one and have me install and take away the old unit. What are your thoughts on this?

[@mr.spittle136]

I havr a weird issue with a microwave that maybe you can help with
I have a GE microwave that doesn't heat. If I unmount the control panel and either hold it slightly to the side of the normal mounting position, or let it hang, the microwave will heat with no issues. Once I reseat the control panel, it goes back to not heating.
Ive tried this back and forth several times and observed to see if wires or harnesses or switches were moving but nothing seems to be out of place when the board is seated into its mounting location.

[@amosmukuka1143]

Sir what could be the problem if the microwave is flickering once the door is open and when you close it,it wants to start but it flickers once and goes quiet

[@jasonhawkins1627]

Main fuse is blowing as soon as I plug in the microwave could it be the transformer?

[@79aac]

Great lesson Mr. Zilka! As always!
I've got a question though.
The tests show presence of L1 at the transformer, but only when you turn the MW On. According to the diagram, there are no switches on L1 to the transformer. The circuit is interrupted (in normal operation) by the relay on the N side. Doesn't that mean that there should always be voltage at the transformer (to ground) regardless of whether the MV is running or not?
Is that a schematic from another machine or am I missing something 😁?
Thank you!

[@riz65]

I will have to rewatch the video, but L1 should be present as ling as the door is closed and all the safety fuses are ok, can you tell me where I might have said it was not there I will rewatch. This video is about 3 years old

[@79aac]

@@riz65 15:10 in the video.
It's not that "you said" it wasn't there. It really wasn't until the MW started running. I'm trying to understand why. Thanks!

[@riz65]

@@79aac ok, then you are correct 120, is at the primary winding as soon as the door is closed

[@riz65]

OK, Yes you are 100% correct, and that was a good question. I re-watched the video "remember I said this was made a couple of years ago." You guess that the diagram did not match the machine. And yes the diagram shown L1 should be all the way to primary of the transformer all the time. So making a test without is running there should be power there when the door is closed. I think it is minute 15:31 where I make the test between ground and black wire L1 at the transformer and didn't have voltage until it was started. The diagram is for a Frigidaire microwave, and the microwave itself is a General Electric Brand. The class was going over microwaves, and one of them the relay was open so we made a class explaining how to search for it. The unit did not have a diagram and I couldn't find one on the internet , so I used the Frigidaire one. I should be back in the classroom in next week or so, school is about to reopen. I should still have that microwave and see if I have any luck in getting the diagram. I will record a second video correcting this.

[@79aac]

@@riz65 Thank you very much for the clarification! I was genuinely curious 🙂.
But didn't mean to take so much of your time.

[@waltersibelius5023]

Fastest way to figure out a no heat problem is amp draw, it will tell you if it low voltage problem or high voltage problem.

[@condor5635]

My microwave amp draw was 2.8 amps today before I replaced the faulty part. What was the defective part?

[@javierq6268]

my microwave as soon I open the door blows a fuse, I test all the switches and they are good, what can be? the MW works normally, but keeps blowing the fuse

[@Marcos-ul6nz]

Hello!What if no 12voltage on
the microwave relay?Whereby no voltage reaching transfomer input 230 volts.

[@johannesvanjaarsveld3800]

Why does my microwave blows the main fuse when I open the door (defy DMO 345 MICROWAVE)

[@Abundance172]

Where would I find information about this class?

[@riz65]

Go to TMMacademics.com you can reach us through the website, and we can explain all of the classes.

[@JP-rf7px]

Tappan Microwave starts, runs for about second. Light, turntable, magnetron all start. Then after a second shuts off. Display says XXXX for a few seconds and then 0. For a while it would do this intermittently, but now all the time so can't use.
Possible problem?

[@terrencemedine8906]

My microwave keeps blowing fuses. I disconnected the 120V AC from the transformer and ran the microwave and the fuse did not blow. I then reconnected the 120V to the transformer and then disconnection the line coming from the capacitor and diode to the high voltage section of the transformer and ran the microwave. The fuse did not blow but as soon as I connect the cable back to the high voltage section of the fransformer the fuse blew. Diode and capacitor test good, the teston the transformer also tested good. Continuity across the low voltage coil good and no continuity to ground, ohms reading from high voltage connection to ground 107 4 ohms. Also across the connector to the magnetron reads 0.3 ohms. What is blowing the main fuse? Thanks in advance

[@rebelroar78]

Radiation leak. The fuse blows when even a small amount of radiation leak is sensed.

[@user-gy4re4ys4l]

Q.. Michroton is working, heating is ok, but the fan and disc motor is not running, what's the problem?

[@danm3188]

often a relay controls those along with the light, so possibly a bad relay.... does the light come on when running?

[@robertgarzamedina767]

Will not start

[@Charles-in3zt]

At 1:47 he states that the monitor switch is normally open and not closed. This is incorrect I believe, In another video Rick says just the opposite, The monitor switch only closes when the door is closed and is a normally open switch.

[@adalbertus777]

In a properly working microwave oven, with the door closed, the monitor switch is open, since its terminals connect Line and Neutral. When you open the door this switch creates a short between L and N but at the same time (or to be precise, just very shortly before it happens) the other two switches open, breaking the circuit so the fuse doesn't blow. Monitor switch is a safety device. Its only purpose is to create that short and blow the fuse when the door is open but the other two switches failed (i.e. they stay closed). When reading a diagram it's good to pay attention to the annotations describing the conditions (or states of operation of the unit) it depicts. Especially for schematics with switches or relays. In case of mv ovens, some diagrams show connections when door is open and others when door is closed. By opening/closing that door you mechanically change the state of switches, so without that note you wouldn't know under what condition the device was when the schematic was drawn.

[@riz65]

You are correct i must have misspoke the monitor is normally closed the Teo other switches are normally open if I said that