Microwave HV Transformer Melted

Sorry to read about your problem, I hope this helps you out.

You can many different issue's

1. Blown fuse in HV transformer primary circuit or HV fuse (if used).
2. Bad connections (particularly to magnetron filament).
3. Open thermal protector or thermal fuse.
4. Open HV capacitor, HV diode, HV transformer, or magnetron filament.
5. Shorted HV diode, HV capacitor (will blow a fuse), or magnetron.
6. Damaged protective VDR from filament to chassis (not commonly used).
7. Defective HV relay (not commonly used).

Microwaves must be serviced by technicians due to the inherent dangers involved in repairing these appliances. Internal capacitors can retain a lethal electrical charge even though the unit is completely unplugged. A microwave radiation leakage test must be performed on the unit following any internal component repair.

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Sorry to read about your problem, I hope this helps you out.

No heat but otherwise normal operation.
Possible causes:

1. Blown fuse in HV transformer primary circuit or HV fuse (if used).
2. Bad connections (particularly to magnetron filament).
3. Open thermal protector or thermal fuse.
4. Open HV capacitor, HV diode, HV transformer, or magnetron filament.
5. Shorted HV diode, HV capacitor (will blow a fuse), or magnetron.
6. Damaged protective VDR from filament to chassis (not commonly used).
7. Defective HV relay (not commonly used)

Microwaves must be serviced by technicians due to the inherent dangers involved in repairing these appliances. Internal capacitors can retain a lethal electrical charge even though the unit is completely unplugged. A microwave radiation leakage test must be performed on the unit following any internal component repair.

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you have a problem with your magnetron tube, and when the magnetron tube goes bad, the diode almost always goes out with it. you should be able to order a replacement tube from your manufacturers website, if you cant let me know and ill try to help you more.

here are the steps to replace the magnetron tube, if you want to do it yourself that is. if you have a professional do it, it can be pretty costly.

1. Unplug Microwave at least few hours before
2. Remove Microwave from above oven range by somebody holding Microwave from ground unscrew the screws from cabinet
3. Remove top cover of Microwave
4. Make sure to keep screws correctly in a place you remember what goes where
   
5. Make sure capacitor is discharged, GE manual inside Microwave says capacitor will discharge within 30 seconds once it is off. As a precaution check the voltage in capacitor to make sure there is no electricity
   
6. Remove other panels around magnetron part
7. You need to remove lot of connecting wires, should be careful to note down what goes where
   
8. If possible take digital photos to refer back when you put everything back together
   
9. You may need to remove transformer to easily remove and replace Magnetron. If you can't remove Magnetron easily then remove bottom panel of the Microwave and remove transformer
   
10. Now it should be easy to remove magnetron
    
11. Replace new magnetron and screw it. We had to put one outside part from old magnetron to new one because new one was missing that. Check to make sure both old and new one are exactly the same
    
12. Make sure put all wires properly back
    
13. Now put transformer back and screw it
    
14. Put capacitor panel in place and screw it
    
15. This might be a good time to test the Microwave to make sure it works fine now
    
16. Now cover the top panels and start to screw everything
17. Once everything assembled put the Microwave back above range put screws from top

When the microwave is not heating, that means the magnetron is not working. This is what provides the heat to the microwave. I do believe the magnetron has a 10 year warranty.

If you wish to replace it, here is how:

1. Unplug Microwave at least few hours before
2. Remove Microwave from above oven range by somebody holding Microwave from ground unscrew the screws from cabinet
3. Remove top cover of Microwave
4. Make sure to keep screws correctly in a place you remember what goes where
   
5. Make sure capacitor is discharged, GE manual inside Microwave says capacitor will discharge within 30 seconds once it is off. As a precaution check the voltage in capacitor to make sure there is no electricity
   
6. Remove other panels around magnetron part
7. You need to remove lot of connecting wires, should be careful to note down what goes where
   
8. If possible take digital photos to refer back when you put everything back together
   
9. You may need to remove transformer to easily remove and replace Magnetron. If you can't remove Magnetron easily then remove bottom panel of the Microwave and remove transformer
   
10. Now it should be easy to remove magnetron
    
11. Replace new magnetron and screw it. We had to put one outside part from old magnetron to new one because new one was missing that. Check to make sure both old and new one are exactly the same
    
12. Make sure put all wires properly back
    
13. Now put transformer back and screw it
    
14. Put capacitor panel in place and screw it
    
15. This might be a good time to test the Microwave to make sure it works fine now
    
16. Now cover the top panels and start to screw everything
17. Once everything assembled put the Microwave back above range put screws from top

Id check the high voltage connectors on the magnitron. Look for any black scorching... Pull them off, clean them and plug them back in. There are only two wires, so ~ it wont take all day to do it.
Obviously on a discharged microwave and unplugged (stating the obvious)....

I went on-line and found a site that gave answers to similar problems. I found that no power to the the control board usually meant a transformer issue. I checked the leads on the transformer (with a meeter) and found that it was shot. Now I need a replacement transformer, at a reasonable price, or else I will purchase a new Microwave.

Kenmore model 665.68682891

hi my name is mark, sounds like you burned up the high voltage transformer or the fan motor. or the transformer for the control board. if oven cycles but does not heat its the HV transformer. hope this helped. thanks for your question.

could be door switches could be pcb could be mag, cap or hv transformer.. Its really just a guessing game but one of the above is defo the cause best to get a tech in to have a look or get it replaced whichevers best for yourself

Sounds like you just fried your magnetron. Normally when they go bad, they make a very loud noise like what you described. The smell concerns me because you may have ruined the waveguide as well. If the magnetron burns through the protective painted surface of the waveguide, the waveguide is ruined. In most microwave ovens this means replacing the entire unit because the waveguide is not replaceable. Putting a new magnetron in a damaged waveguide will result in the same arcing and eventual failure. In addition to the magnetron, the following components are part of the same high voltage network: HV Transformer HV Diode HV Capacitor Magnetron Thermal Cut-Out Any one of these components could have also been damaged. I DO NOT recommend taking any voltage measurements inside the HV network. Potentials of over 4000 volts can be reached and make it very dangerous for the do-it-yourselfer. Taking resistance readings with the unit unplugged is strongly encouraged. If you decide to pursue a repair, inspect the magnetron tip and inside of the waveguide first. If the magnetron is melted and/or there are burn marks inside the waveguide, a new microwave may be a in order. This actually may be a better option than an expensive repair. I hope you find this advice helpful.

If your microwave is doing everything, but heating it could be any one of the following components: Magnetron HV Capacitor HV Diode HV Transformer This network works in conjunction to produce the high voltage required to heat. Taking live voltage measurements is dangerous and not recommended. You can, however, do resistance checks on the components with the unit unplugged to see if you can isolate the problem any further. The HV Diode should be mounted somewhere on or near the HV capacitor and will read an open in one direction and a relative short in the other. If you put a meter on the capacitor you should see a varying resistance as the capacitor charges and discharges. There should should be a wiring diagram inside your control panel with the resistance readings for the primary and secondary windings of the transformer and the filament of the magnetron. In a nut shell, you probably have either a bad magnetron or a bad diode. Those are the two components that fail more frequently. Of course, double check all your interconnecting wires too. Good luck and let me know if this helps.