1 goes to RCA signal input
2 goes to RCA ground
3 goes to the negative fused B- rail (all the negative output collectors are attached to this Q108 to Q117C watch out, the PL schematic has errors)
4 goes to the negative side current limit resistor junction of R127 and Q110E (appears to be a yellow wire in your picture)
5 goes to bus bar ground between the 2 bulk caps
PNP goes to the base of Q108
6 goes to the output (junction of all the 0.33 ohm emitter resistors)
7 goes to the positive fused B+ rail (all the positive output collectors are attached to this Q107 to Q116C watch out, the PL schematic has errors)
8 goes to the positive side current limit resistor junction of R110 and Q109E
9 goes to the base of Q107
10 goes to the emitter of Q107
11 goes to unfused B+
12 goes to unfused B-