Well, I spent some time looking last night and ran across a guy that made a post about having a schematic. I emailed him and got a much clearer copy in my inbox this morning. I'll still have to add in a few values that aren't real clear, but it's way better than starting off with the GIF image I had.



 Baja

Yea, I had a feeling that was where I was headed.... looks like I'm gonna need an eye loupe and a bottle of asprin

 This point to point is kind of a pain to follow, but I should be able to trace it out and get a schematic up. Thanks for all of the help guys!

 Baja

I don't like PCB Valve gear much.
Can't even get the red knobs off the front on this Fender,

Surely you don't think the knobs were stuck because it is a tube amp?  Like the same pots and knobs on a solid state amp would slide right off?   Maybe a little heat will help loosen them.

with just one half of the brown winding working, you still ought to get your 30vDC rails.   You could lift D108-111 to remove the fan influence and see if your voltage comes back down.


AHA!   I just looked more closely at the schematic, and finally realized what I was seeing.   There is a reason the fan circuit does not reference ground.  I was trying to figure how the same set of 23v wires could make +/-30vDC or 60v, and still make only 40v in the fan supply.

But it just sank in that the fan supply runs off one of the low voltage wires and one of the high voltage wires.  In other words the fan is running off what amounts to a 34-0-23 "winding".   Since it has no ground reference, the lopsidedness matters not.

But if one of the diodes in the fan supply shorts, or the C116 or C117, or not swure what else, it would wind up shorting the red wire to the brown wire, and that might be the reason the brown wire haqs burnt open inside the tranny.

So:
1.  Lift the four fan supply diodes.  Check them while there for shorts.  See if the remaining low voltage wire now allows the +/-30vDC down there that would allow the Vregs to come home.

2.  Open up the transformer to see if you got lucky and it might be repairable.

3.  Solve the fan supply.  Look for anything in it that might be shorted.

 @ Rutger, Glad to hear it worked out.

I just made a fluff up job of using a pre existing power amp board to run multiple opamps for a foldback I'm trying to get up and running on the cheap and forget to check the Zener regulation. 
So now I have to pull the 1k resistors (need 330 R) off a small tight space and I've stuffed the cheap PCB tracks from the power amp circuit board.
So back to the bench to make a whole new board for the power amp and PSU,,,,which I should have done in the first place.
Serve me right for cheating too much.


and Thanks Roly,, yep I hang my head in shame, should have known what E stood for.
I doubt I'll ever totally conquer the mountain but I pick up a lot from wonderful folks like you and I feel more confident to take on slightly harder stuff but I try not to get in too deep cause I know darn well I'll get caught out if I'm to cocky about it.

I say that as I take on another repair which erks me a bit,,I don't like PCB Valve gear much.
Can't even get the red knobs off the front on this Fender, broke the pot shaft on one already.

Surprising how little electronics is actually involved in repairs
as a lot seem to be more mechanical issues.

The leaky power caps where easy to fix but now it's turned into a major
headache that will take a lot longer to fix.
Such is life.

Phil.

Arrh of course,,Very good thought .
Not only is Jaun good looking He is clever also.
Phil.

You are a better man than myself if you can grasp all that.
so good on you

I just stick to simple stuff to explain it.
The best explanation of distortion I read,, (so long back can't remember who/where but likely one of the guitar focused sites)
Went simply thus;
*Half wave distortion followed by Square wave dist.*
If you simulate some of those old famous Valve rigs that is indeed what happens.
the triodes produce the rattle and the power stage squares it off at higher power.

The rest is tone shaping.
The trick is getting the signal swings to line up at each stage if you want the dynamics to happen.
Of course if all you want is fuzz with no dynamics then throw away that idea and turn everything up as far as you can and start playing around with tone shaping.
Phil.
 

Do you have a common psu or does each unit run from a separate supply?

Have you got ground connection between units?

Is the output of 1st unit decoupled from 2nd unit? (i.e a cap)

If you are still stuck others here will likely know more.
Hey at least it makes a noise which is better than no noise. 
Phil.

So the brown wire should be at 22 volts correct? If so I'll get a look at the transformer connections inside to see if anything came disconnected. Should I still disable the fan circuit for further testing or are we at a standstill until I fix/get a transformer?

Well, if you have a blurry but accurate schematic, redraw it, and then add the parts values as you see them in the actual amp thet's on your bench.