Fender '57 Custom Pro Amp Service Manual

[Tom Phillips]

Anyone have a copy of the Fender '57 Custom Pro Amp Service Manual?
I have a client asking about service and maybe mods to his '57 Custom Pro Amp and I wanted to take a look at the circuit configuration that Fender used in advance of getting the actual amp in my shop.
TIA,
Tom

[Jazz P Bass]

I do not have that one.
My feeling is that it is not at all that different from the original.

[Tom Phillips]

I do not have that one. My feeling is that it is not at all that different from the original.

I know I won't need it to service the amp if my client decides to send it to me. However, I was curious to see the documentation and was surprised that the service manual for this amp doesn't seem to be available.

[g1]

I think it is too new and Fender has tightened up schematic access for non-authorized svce. centers.

[Tom Phillips]

I think it is too new and Fender has tightened up schematic access for non-authorized svce. centers.

That's what I figured. I used to have access but it became too difficult to maintain for the
benefit."

[The Dude]

I don't have a schematic, but recently worked on one that had a dead shorted PI coupling cap.

[pdf64]

How about asking Fender directly?

[Delta362]

Here you go

[Tom Phillips]

Here you go

Thanks for the schematic Delta362.

Interesting. I see from this Rev A drawing that other information on line is not necessarily correct. Specifically that the Fender Owners manual states that "the custom transformer will switch to 4-ohm operation when both [speaker] jacks are used." That kind of info is why I wanted to see the actual documentation. It will help me respond to my remote client's questions about the amp.

Cheers,
Tom

[Helmholtz]

To me the most interesting detail of the cicuit is that the whole supply current runs through the choke. Must be rated for 200mADC or more.
Consequently sag will be significant and power output rel. low.

[Tom Phillips]

...sag will be significant and power output rel. low.

Turns out that Fender specs this amp as 26W power output. That will be a surprise to the crowd that automatically labels a 2 X 6L6 amp as 50W.

[pdf64]

No screen grid resistors!

[Helmholtz]

No screen grid resistors!

Yes, I noticed. Just like the original 5E5-A circuit.
I guess Leo didn't want to sacrifice even more output power given the limited grid drive from the split-load PI.