Is My 3-6PT Power Transformer Usable?

[Jim J.]

Hello again all! I hope your restoration projects are going well.

I posted earlier on a topic regarding the power switch wiring: http://sunnforum.ampage.org/index.php/topic,10147.0.html. Thanks to all for reading this post.

I think part of the problem is my power transformer. Coming out of a Sunn Sentura II that I am working on is a PT labeled 3-6PT. I am wondering if it is salvageable for use with a tube rectifier. Basically, I believe that there is one yellow wire missing, which, according to the schematics for this amp, goes to two pins on the rectifier socket. I have identified the wires as I think they may be and tested them for resistance as well:

Two green wires: heaters
One white: a primary
One black: a primary
Two red wires: the high voltage secondary wires
One what appears to be orange wire: maybe originally one of the low voltage wires that goes to the rectifier with the other one MIA.
One red/blue wire: bias
One red/yellow: center tap

Basically I am wondering if anyone can shed some light on whether these are correct identifications. If I want to use a tube rectifier and restore the amp to specifications on the schematics, can one low voltage yellow wire be used by splitting it? If not, can someone restore this transformer and make it work right by wiring in another yellow wire?

I opened the transformer by removing the bells and did not notice anything unusual such as wires tucked underneath or something that was cut. I am including pictures so that it clarifies my predicament visually. Thanks for the feedback in advance!

Jim.

[loudthud]

That hole where the wires exit the end bell doesn't look right. Re-winding the transformer will be more expensive than getting a new one. A replacement is available from Triode link: http://www.triodeelectronics.com/mq782.html

[Jim J.]

I have nothing to compare it to. But I've seen the one at Triode and I can see mine does not match theirs. I agree that with a vertically mounted PT it would be strange for the wires to come out the side instead of from the bottom. I'll be letting my client know his options about a new PT. Thanks for the direction!

[Jim J.]

The transformer was usable. Someone had modified this amp to solid state rectification and had it wired wrong. Since the yellow wires aren't used in this this situation, the PT was salvagable. The customer was okay with this mod to get it working without having to buy a new PT. We'll maybe restore it at another time. Still sounds superb!