Fender Pro Reverb AA1069 Doghouse Capacitor Layout?

[NotWesYet]

Hi All,

I am rebuilding a '71 Silverface Pro Reverb which I have owned since new. About 20 years ago a tech "restored" it and after repeated problems I looked at the chassis and found a total mess. So I have been rebuilding it from pots to tube sockets to turret boards and components.

I am at the point of rebuilding the doghouse board with a new turret board from Doug.

I have looked at Rob Robbinet's DIYLC files but none match what is present in mine. The cap values and resistor values are correct in mine, but the wiring just doesn't match anything I can find.

Would anyone have the proper layout or could provide a link?

Thanks,

James

My capacitors are laid out as on the right.

https://el34world.com/charts/fenderservice7.htm

It is the wiring that doesn't seem to match any description I can find.

[shooter]

looked at Rob

did you look at Doug's?
I've used them, they match about all the "typical"

EDIT:
adding link;
https://el34world.com/Forum/index.php?topic=24156.0

[NotWesYet]

looked at Rob

did you look at Doug's?
I've used them, they match about all the "typical"

I have. Thank you. But the do not have the wiring connections. Or maybe I am looking at the wrong pages.

Here's a link to the one that was installed in mine.

https://i.ibb.co/mysFyCL/IMG-2093.jpg

Here's what he has for the Bandmaster, the same AA1069 circuit.

https://i.ibb.co/kxV6SdN/Robs.png

Mine has the black wire on the negative side of the 20uf middle cap.

And then another greenish wire to the next negative side of the 20uf cap.

I am afraid I am overlooking something obvious and thought it would be best to ask.

[shooter]

'71 Silverface Pro Reverb

draw it up in diy just like the schematic, note how you think yours is different

[NotWesYet]

'71 Silverface Pro Reverb

draw it up in diy just like the schematic, note how you think yours is different

Thank you. That is a good idea!

[shooter]

Rob's is 2 Ecaps in series with "balance/bleeder" resistors (if black wire is ground)
didn't compare to Fender

[NotWesYet]

Rob's is 2 Ecaps in series with "balance/bleeder" resistors (if black wire is ground)
didn't compare to Fender

One thing I noticed in Rob's diagram as white is listed as "to preamp ground" but in the full diagram it runs to the power ground.

So the negative side of the first 20uf and the negative side of the last 70uf are connected together at the power amp ground point.

In the Fender schematic it indicates three black to ground, one on each side of the board about mid way, with the other runs to the common ground where the red and yellow wires are a twisted pair to ground.

[sluckey]

See if this helps. Start looking at 8:00.

[2deaf]

Your picture looks a lot like the doghouse in a '71 Super Reverb.

[NotWesYet]

Your picture looks a lot like the doghouse in a '71 Super Reverb.

This really helps. It not only confirms the previous wiring had not been modified by the tech, it confirms the wire locations. And it also leads (no pun intended) me to understand what the reoccurring problem was and the source of the problem.

The tech had worked on it again and again with hum occurring when you came within proximity of the normal channel inputs. You didn't have to even touch them, just placing your hand near as if you were plugging in would cause hum.

The orange wire to the normal channel ground plate was in a blob of solder which is suspect was a cold solder as well. When I pull the brass plate out to clean off as well as remove all the old solder I found I could not get it back in correctly.

There was solder residue underneath the plate keeping the brass ground plate from making full contact to the chassis. I chipped those off, and cleaned the chassis using an abrasive.

I had to use a heat paint gun to get the solder off the brass and a chisel and hammer on parts of the chassis.

Hopefully, this solve the issues!

Thanks for everyone's help. It is truly appreciated!