• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake
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FIXED JVM1860WF001 GE Profile Spacemaker XL1800 microwave not heating

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Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
28
Location
Hawaii
Model Number
JVM1860WF001
Brand
GE
Age
More than 10 years
I have a GE Profile Spacemaker XL1800 microwave.
I indicated more than 10 years old, but it may be less.
It stopped heating (ran fine but nothing got hot) so I removed the front control panel, discharged the capacitor, and started checking things.
I found one of the two ceramic fuses blown, so I replaced it, but it still did not heat.
I checked it again and found the new ceramic fuse had blown.
So I discharged the capacitor and removed the top cover.
I checked the high voltage diode, capacitor and magnetron.
The high voltage diode tested good (with a 9 volt battery).
The capacitor tested bad with a dead short (0.00 ohms on my digital meter) across the two leads.
Both leads show infinite resistance to the body of the capacitor.
The magnetron seems to be bad as there is a dead short (0.00 ohms on my digital meter) across the leads.
Information on the internet indicates that the resistance of a good magnetron could be between about 0.8 ohm and 2.0 ohm, but is should not be zero.
Both leads show infinite resistance to the body of the magnetron.
I repeated all tests using my old non digital multimeter and got the same results.
My questions:
Is my magnetron bad?
Any comments on both the capacitor and the magnetron being bad?
If one fails, does it often take the other one out as well?
Which fails first?
Always interested to learn.
Wondering if it's worth fixing if both capacitor and magnetron are bad.
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
4,257
Location
Ontario, Canada
The magnetron seems to be bad as there is a dead short (0.00 ohms on my digital meter) across the leads.

On what resistance scale? It should usually be less than 1 ohm and zero is less. So depending on the resistance scale and the calibration of the meter, that reading could be normal.


The capacitor tested bad with a dead short (0.00 ohms on my digital meter)

That sounds like it's defective.


Daddyfix said:
My questions:

Is my magnetron bad?
Any comments on both the capacitor and the magnetron being bad?
If one fails, does it often take the other one out as well?
Which fails first?

Maybe not.

It might be possible but would be pretty unusual IMO.

It could but it is definitely not a forgone conclusion. Both frequently fail without affecting the other.

I've never seen any statistics.



Since the capacitor definitely looks to be bad by what you said but the magnetron tube readings might be Ok, I might suggest trying the just capacitor first.

LINK > JVM1860WF001 HV Capacitor



JMO

Dan O.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
43,740
Location
Murray, Utah 84107, United States
I agree with bigbuck. The mag tube is most likely ok.
C-HV Testing.jpg
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
28
Location
Hawaii
Thank you, Dan and Rick.
That was very interesting and informative, that it is unusual for both to be bad.
To answer Dan on how I tested the magnetron:
My digital meter is an Amprobe AM-510 and I was using auto range.
I just did it again but selected ohms range.
I got 0.00 which is the same as what I got before and is also what I get if I touch the probes together.
My moving coil meter is a TMK Model 200 and I selected ohms x 1 range.
I calibrated to 0 by touching the probes together and setting the ohms adjustment.
The magnetron resistance shows 0, the same as touching the probes together.
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
28
Location
Hawaii
Thanks, Rick!
I wanted a reasonable degree of confidence that I won't have to replace both.
Or that the magnetron wasn't also bad and would take out the new capacitor.
I will order a capacitor, install it and report back.
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
28
Location
Hawaii
Congratulations, Dan and Rick!
You guys were right.
I replaced the capacitor, and the microwave is heating now.
The magnetron was good as you guys said.
I really appreciate the help.
 
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