Smoking Transformer

techchris · 2551

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Offline techchris

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on: June 24, 2014, 05:59:25 PM
Hey guys,

I just finished my building crack. I did the voltage tests without power and they were all perfect. Then I plugged the power in and after a few seconds, the transformer got very hot, began to smoke and the fabric on the bottom of it started to expand. I unplugged immediately. Now the bottom of the transformer feels kind of "crunchy", like molten and hardened plastic...

Here are some pictures of my Crack, but I'm pretty sure, that the wiring is correct. I hope that you can help me,

Christoph




Offline Doc B.

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Reply #1 on: June 25, 2014, 05:29:54 AM
I repaired one exactly like that last week. The builder installed one of the UF 4007 rectifier diodes backwards. Check for that.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline techchris

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Reply #2 on: June 26, 2014, 06:13:49 AM
Thanks for answering, but the UF 4007 rectifier diodes are definitively oriented right. I checked everything two more times and wasn't able to find  anything wrong. The only unusual thing was if I put the two leads of my volt-ohm meter on the first and second "pin" of the transformer (on the front row, to the side with the headphone jack the volt-ohm meter beeps. This should not be the case, right? the two pins are not connected on the outside


Offline Doc B.

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Reply #3 on: June 26, 2014, 12:06:14 PM
Based on your findings and last week's episode we are going to check to see if we may have gotten a couple of miswired transformers from our winder. I'm not at work this week, but I will ask PB to check if that is in fact what has caused the problem. Once we have established whether or not that might be the issue we will definitely help to get you up and running ASAP.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Nathan

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Reply #4 on: June 26, 2014, 02:43:52 PM
"I did the voltage tests without power"

How do you do that?

Crack/Speedball, SEX 2.1/C4S, Bryston BHA-1

Sennheiser HD600/Cardas cable, Beyerdynamic T1 2nd Gen, Hifimam HE560/Hifiman balanced cable

Offline Doc B.

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Reply #5 on: June 26, 2014, 05:05:35 PM
We are not finding any issues with our transformers. So I think the next best step is for you to do the resistance checks again and let us know if there are now any that are not within spec.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Doc B.

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Reply #6 on: June 26, 2014, 05:10:32 PM
Do you have a miswire on terminals 4 and 5 on the nine pin socket? It's difficult to tell in the photo.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline knightzor

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Reply #7 on: June 29, 2014, 03:31:27 PM
Hi Christoph,

If it helps, I had an overheating and smoking transformer issue recently and for me, the problem was not a miswire but I believe I had a cold solder on terminal 13 (which meant the output capacitor was not being utilised properly). I would say make sure your resistances for the asterisk terminals are indeed rising because that's what stumped me originally. My resistances were all fine except a couple of the asterisk terminals. I reheated all the solder joints around the transformer and it ended up fixing the problem. Reason I say terminal 13 was the problem for me was because the solder joint just didn't look right but after reheating it and adding some solder, it looked better (shiny, concave).


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