1976 Fender Twin Reverb Layout Diagram?

[keithb7]

Hi I am working on a 1976 Fender Twin Reverb. I have been able to locate a schematic, but not a layout diagram. Did Fender stop drawing layout diagrams after the AA270 circuit? That seems to be the latest layout I can locate on line.
If anyone has a 1976 Layout, I'd love a copy for reference. Thanks, Keith

[keithb7]

The background to this enquiry is a 1976 TR that I am working on. It was heavily modded. The owner asked me to remove all mods and create a stock circuit. We talked about a non-Master volume circuit. So I decided to go with the AA270 circuit. I have rewired the amp and I am about to recheck all my work against the AA270 schematic and layout. I would like to view the 1976 layout if possible, as this was how the amp started out. The pic is how the amp looks today, re-wired to an AA270. Thanks.

[Leo_Gnardo]

I would like to view the 1976 layout if possible, as this was how the amp started out. The pic is how the amp looks today, re-wired to an AA270. Thanks.

I have no '76 layout, but the main differences between 76 and earlier Twins is 1) pull boost circuit & MV, 2) power supply & bias board moved from the corner to where you show it, 3) hum balance control.

Also, mid 70's twins tended to use a 0.01 uF disc cap to feed the master volume. Earlier versions used a 0.001 uF then even earlier 500 pF. I like to use 0.001 uF 630V Mallory 150 film cap here.

I'd say what you have is plenty close enough for rock n roll. "If it sounds good it IS good."

[pdf64]

The MV pot looks to be a regular type rather than having the pull boost switch?
I guess i may have been replaced.
The 'pull-boosted' tone wasn't good, so not a bad thing.

[Leo_Gnardo]

The MV pot looks to be a regular type rather than having the pull boost switch?
I guess i may have been replaced.
The 'pull-boosted' tone wasn't good, so not a bad thing.

There was another pull boost Fender tried, on the vib channel volume control. Similarly, it was naff so just as well left out. It was done by 'borrowing' some signal from reverb drive, sounded like poop.