GE microwave no Heat.

Thread Starter

frank55

Joined Dec 6, 2013
286
Hi guys; i have here a Ge microwaves that turns on normally all functions are running including fan but doesn't heat anything,i tried another HV diode and still no heat,i know that more likely to be the Magnetron, which costs too much money it's not worth it, but before i through it out,could it be the big Cap?
thanks.
 

#12

Joined Nov 30, 2010
18,190
could it be the big Cap?
Yebut...it's bloody dangerous to be going around measuring when it's live. Check each part that isn't the magnetron, then check that power line voltage is arriving from the controller. If everything else is good, you have a dead magnetron by the process of elimination. Don't forget to check the overheat safety attached somewhere on the magnetron.
 

Thread Starter

frank55

Joined Dec 6, 2013
286
Thanks guys i found the issue, it was Temperature Control Switch Thermostat,believe it or not, all info available pointed to Magnetron,or HV Diode,or HV cap,or switch, well i started by changing the HV cap,then checked cap which was good,so luckily i had some Temperature Control Switch Thermostat in my scrap and it started to heat,almost went to land fill if i did not have those Temperature Control Switch Thermostat,since everything pointed to Magnetron which costs 100 bucks,
this is a GE microwaves it's almost new,i really needed one, mine was a GE but small and old,the door did not open easy,so one more out of land fill.

http://www.ajmadison.com/cgi-bin/ajmadison/PEB2060.html
 

#12

Joined Nov 30, 2010
18,190
Well, good thing it has extra microprocessors or it wouldn't have broken in the first place.:)
/[sarcasm off]
 

Thread Starter

frank55

Joined Dec 6, 2013
286
Well, good thing it has extra microprocessors or it wouldn't have broken in the first place.:)
/[sarcasm off]
What you mean? this is a very low end MW i Know with not very good reviews but for what it costed me i think i can't complain!
 

ian field

Joined Oct 27, 2012
6,539
Yebut...it's bloody dangerous to be going around measuring when it's live. Check each part that isn't the magnetron, then check that power line voltage is arriving from the controller. If everything else is good, you have a dead magnetron by the process of elimination. Don't forget to check the overheat safety attached somewhere on the magnetron.
The 2kV from the transformer secondary can shift about 1/2A, pretty much as good as "Old Sparky" - the voltage doubler puts about 4kV on the magnetron - still enough current for lethal effect, and it can jump further.

Living in a block of flats - I often "find" discarded microwave ovens. Often they only need minimal repair and/or cleaning. Currently I have one in the kitchen living out its death throes, another tested and lined up ready, and 2 more stored in the garage (untested). Sometimes I salvage any useful spares when scrapping an old one, but its getting increasingly not worth the effort. There's one left in the bin room for a couple of days now and I haven't bothered to look at it.

The situation is probably similar anywhere with kerb collection.

An open circuit coupling capacitor in the voltage doubler isn't impossible, but they usually fail short circuit. Same with the diode stick - the magnetron can also develop an internal short. Anything shorted on the secondary side should blow the fuse, but shorted turns on the transformer sometimes happens.

The most likely cause of no current draw on the secondary is a low emission magnetron - excessive use of defrost strips the cathode, unless you bought an expensive model with separate heater transformer.
 

#12

Joined Nov 30, 2010
18,190
What you mean? this is a very low end MW
You have:

Uses built-in sensors to automatically set power and time based on food moisture levels.
Automatically defrosts for a specified amount of time or weight.

I have wind up timer.:D
A wind up timer doesn't do all those auto measuring functions, a microprocessor does.
 

Thread Starter

frank55

Joined Dec 6, 2013
286
The 2kV from the transformer secondary can shift about 1/2A, pretty much as good as "Old Sparky" - the voltage doubler puts about 4kV on the magnetron - still enough current for lethal effect, and it can jump further.

Living in a block of flats - I often "find" discarded microwave ovens. Often they only need minimal repair and/or cleaning. Currently I have one in the kitchen living out its death throes, another tested and lined up ready, and 2 more stored in the garage (untested). Sometimes I salvage any useful spares when scrapping an old one, but its getting increasingly not worth the effort. There's one left in the bin room for a couple of days now and I haven't bothered to look at it.

The situation is probably similar anywhere with kerb collection.

An open circuit coupling capacitor in the voltage doubler isn't impossible, but they usually fail short circuit. Same with the diode stick - the magnetron can also develop an internal short. Anything shorted on the secondary side should blow the fuse, but shorted turns on the transformer sometimes happens.

The most likely cause of no current draw on the secondary is a low emission magnetron - excessive use of defrost strips the cathode, unless you bought an expensive model with separate heater transformer.

Thanks Bro for your very good info;although on my previous post i stated that i found the issue, it was Temperature Control Switch Thermostat,believe it or not, all info available pointed to Magnetron,or HV Diode,or HV cap,or switch, well i started by changing the HV cap,then checked cap which was good,so luckily i had some Temperature Control Switch Thermostat in my scrap that i tried and boom it started to heat up ,almost went to land fill if i did not have those Temperature Control Switch Thermostat,since everything pointed to Magnetron which costs 100 bucks, thanks anyway.
 
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