Heads up, I was looking over the comments at FSB, and it seems C4 may also be 2u2, not 10u. (cap from Bias 3 to ground).
Both the schematic and Johnk had C4 as 10u, but the circuit designer Brian mentioned on FSB he thought c4 was 2u2 and the very first gut shot post listed it as 2u2.
You may want to socket both caps (c4 & c7) and try both 2u2 and 10u.
Mike
I've updated the layout accordingly.
1978 Gibson Les Paul Standard, Cherry Sunburst