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johntech

Ge monogram ZGU385NSM2SS pesky transformer

24 posts in this topic

Ge gas cooktop no spark. The transformer was not giving any output I replaced the transformer the new one sparked for about 1 minute then failed and tested bad on the primary windings. Did I just get a bad transformer or do I have another problem?

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which winding on the Transformer "opens"

Secondary pins 1, 2, 3 ?

"blows" when a certain Burner is turned ON ?

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With transformer discon I get nothing on the primary windings. I'm a little green at this so bear with me.

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With transformer discon I get nothing on the primary windings. I'm a little green at this so bear with me.

Primary winding OHMs ?

but all (3) secondary winding OHM OK ?

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Disconnect the 2 power supply wires and the
transformer wire harness.
Check the primary winding for approximate
resistance value of 32.8 Ω between the 2 brown
(input) wires.
Check the secondary windings for approximate
resistance value between:
White to red - 2.2 Ω
Brown to red - 196 Ω
Brown to white - 198.2 Ω

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Yes all other windings check ok

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I get nothing at all on the primary windings

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I get nothing at all on the primary windings

same with the "old" Transformer ?

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I never checked the original transformer I just saw no out put voltage. Now I have the original transformer back on and had to leave the job.

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also do an OHM test of the output loads

A shorted load may cause the primary to burn out ..

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I'm kind of in a jam here the first transformer blew right in front of the customer after he had to wait several days for the parts to come in. I'm afraid if I put a new transformer on it will have the same results. Any suggestions would be greatly appreciated.

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... the first transformer blew right in front of the customer

Did it blow up right after powering-up

OR did you do something... turn a Burner ON, etc ?

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I'm kind of in a jam here the first transformer blew right in front of the customer after he had to wait several days for the parts to come in. I'm afraid if I put a new transformer on it will have the same results. Any suggestions would be greatly appreciated. When I plugged it in the center burner was in the on position and immediately started sparking. I turned it off and back on it sparked one more time and then nothing

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I'm getting continuity on red and white .0002

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I'm getting continuity on red and white .0002

is that with the Transformer disconnected ?

the Transformer Red and White should be about 2 OHMs

The "harness" should be higher than 60 OHMs

.That's the 12vAC that goes to the LED's built into the Harness

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Yes that's disconnected. Do you think there is a short in that light switch

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... Do you think there is a short in that light switch

take a close inspection of the Harness and the LED Boards

or one of the "regular" Diodes may be shorted

or one of the wires of the Valve switch is shorted to chassis / ground

 

http://www.repairclinic.com/referral.asp?R=154&N=1473713

Wire-Harness-WB18T10411-01583644.jpg

 

lwb0.jpg

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If the boards visually check out ok then what are the chances of it being the led harness opposed to the spark harness? Both these parts are special order and won't ship for a few weeks I am going to go back out there and try to pinpoint the prob before I order. Anything else you recommend I check while I'm there

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If it's the 12v line causing the problem,

the 12v line doesn't got to the Spark Module

 

Did you test the Diodes for shorts ?

And check for shorts to chassis / ground on the wires of the Gas Valve Switches ?

and inspect those small "chips" on the back of the LED Boards

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Thanks a lot I found a short on that led harness

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Thanks a lot I found a short on that led harness

on the Harness actual wires ?

repairable ?

What seemed to be the cause ?

pictures ?  before or after repair ?

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On a return trip I was not getting continuity with the gas knob turned on the appropriate pins coming from the led harness for the left front burner, I returned again with a shiny new transformer and the led harness which had to be special ordered. I installed everything double checked all of the connections and for 120v to the transformer, I buckled it all back up and plugged it in. I tried the left front burner and I got spark, it seemed weak sounding to me and the led was flickering, then I tried the next burner and got nothing, the rest were all dead, on top of that I started smelling an electrical burning smell it was the switches on top of the gas valve I unplugged and immediately checked my transformer and I had infinite on the primary windings. I checked my led harness and that checked out ok then I started checking the wires running from the transformer to the switch harness to ground and sure enough on that red wire I was getting 1.63 ohms to ground. Guess ill go back out with a new transformer and a switch harness, any other thoughts would be greatly appreciated.

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