Microwave not Heating
 

I have a pair of virtual twin GE's, 1600 series, that aren't heating.
All else appears to be normal. I've replaced the HV diodes with no
luck.

After discharging, all resistance checks appear to be normal.

HV side 70 ohms, primary 1, open to chassis.

Filament, 1, open to chassis.

Cap is hard to measure. I have a cheapie analog meter that only does
x1000, I get a very slight needle deflection when across the cap
terminals followed by an immediate return to open. My digital meter
has a very slow response time. I see it changing scales from M to K
but by the time it shows a number it is back to M (the internal
resistor of the cap). Both terminals open to cap case.

When running there is a slight to moderate hum. An inductive voltage
tester shows lots of power on the HV xformer, and it cycles with the
power relay when set to 100% on. The hum cycles with the voltage
presence.

I'd guess either cap or magnetron, any suggestions? On one of the
units, the HV diode was shorted (nothing visible) while as the other
one did not test as shorted.

Thanks.

Microwave not Heating
 

Backhand writes:

I have a pair of virtual twin GE's, 1600 series, that aren't heating.
All else appears to be normal. I've replaced the HV diodes with no
luck.

After discharging, all resistance checks appear to be normal.

HV side 70 ohms, primary 1, open to chassis.

Filament, 1, open to chassis.

Cap is hard to measure. I have a cheapie analog meter that only does
x1000, I get a very slight needle deflection when across the cap
terminals followed by an immediate return to open. My digital meter
has a very slow response time. I see it changing scales from M to K
but by the time it shows a number it is back to M (the internal
resistor of the cap). Both terminals open to cap case.

When running there is a slight to moderate hum. An inductive voltage
tester shows lots of power on the HV xformer, and it cycles with the
power relay when set to 100% on. The hum cycles with the voltage
presence.

I'd guess either cap or magnetron, any suggestions? On one of the
units, the HV diode was shorted (nothing visible) while as the other
one did not test as shorted.

I'd go with magnetron or bad filament connections but I assume you checked
those. The HV transformer wouldn't fail in a way that didn't result in
smoke or blown fuses. The cap is more likely to short than open and
you do get some response on your DMM. You could compare it to a normal
1 uF capacitor.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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Microwave not Heating
 

On or about 24 Oct 2005 15:53:51 -0400 someone/thing calling
him/her/itself Sam Goldwasser inked the
following:

I'd go with magnetron or bad filament connections but I assume you checked
those. The HV transformer wouldn't fail in a way that didn't result in

Ok, I finally had time to get into it and upon removal of the
magnetron found the antenna nicely burned up, a good 1/4 inch hole
eroded on the top/side.

Called GE wholesale parts (888 239 6832) and they are sending me the
mag/stir kit under the 10 yr. warranty.

Do you think I should get a leak test done? I've not touched the
waveguide or the door at all so it should still be intact.

Thx.

Microwave not Heating
 

Backhand writes:

On or about 24 Oct 2005 15:53:51 -0400 someone/thing calling
him/her/itself Sam Goldwasser inked the
following:

I'd go with magnetron or bad filament connections but I assume you checked
those. The HV transformer wouldn't fail in a way that didn't result in

Ok, I finally had time to get into it and upon removal of the
magnetron found the antenna nicely burned up, a good 1/4 inch hole
eroded on the top/side.

Called GE wholesale parts (888 239 6832) and they are sending me the
mag/stir kit under the 10 yr. warranty.

Wow, I'm impressed they didn't give you too hard a timea bout you're
being killed and suing.....

Do you think I should get a leak test done? I've not touched the
waveguide or the door at all so it should still be intact.

The party line says yes. As a practical matter, if you haven't touched
the door seal, there won't be any issues with leakage from the front.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.