Problem with a power transformer.

[hendo89]

First amp build for me, and I screwed up.

here's the link to the schematic:
Compact Hi-Fi Power Amplifier by Melvin Leibowitz

Everything is constructed, when I went to turn it on for the first time I had a small amount of smoke from my PT. Turned it off immediately and saw that I made the mistake of connecting the two 6.3V wires together before I ran them to the 6C4 tube. I fixed the issue and put some extra insulation around those wires for safety. Took the covers off the PT and did not see any melting or anything to show that it was ruined.

When I went to power the amp again all tubes had power and were getting hot, except for my 6C4 tube. I have gone over everything over and over again and I believe the wiring is all correct, I am wondering if I have burned up part of my transformer beyond use.

What is the best way for me to test this issue??

 

[jayherbie]

Check that winding with dvm you should get a reading of just couple of ohms I suspect that winding has burnt out. You will need to replace the transformer or you could fit a small heater transformer or you

 

[HollowState]

If your amplifier is constructed as in the schematic and you have one 6.3 volt winding in the transformer for all three tubes and two are lighting, then the transformer can't be bad. There must be a break in the filament wiring somewhere, or perhaps a bad solder connection at the socket. Maybe connected to the wrong pin or even a bad 6C4 tube. Keep checking because sometimes you can't see the forest because of the trees.

 

[hendo89]

Hollow, thanks that makes a lot of sense. the 6c4 tube is a NOS tube, i got it recently and it is the first time I have tried to power it up.

And correct, the other two tubes that are running off of the 6.3V are heating up. I'll go back and flood my solder and double check my connections.

 

[TonyTecson]

I am wondering if I have burned up part of my transformer beyond use.

i doubt it....if you were able to turn the thing off as soon as you noticed, then fine...

 

[Junm]

also test the tubes heater pins with dmm if they still have few ohms reading...

 

[N4BBQ]

Sounds like a bad 6C4 or a miswire.

 

[nl3prc]

Remove the 6C4 And check the wires toe the tube maybe the are burnt out.

Also check if there is power on de fillements leads