I'm back from the bushwalk so I'm a bit stuffed but I did think of a few things.
The previous post is one solution to frustration (with a Class D O/P stage?), I hope we can find a less brutal option...
Firstly, in relation to turning on the power transformer:
I then tried activating the transistor Q2004 with 3.3v through a 1n4001 on the PRY pin. This pin says it takes 2.7, which itself comes from a diode at the 3.3v output of an IC on another board. I figure the 1n4001 would be ok as it has a drop of about 1.1v, but maybe 2.2 isn't quite high enough. I was hoping to hear an audible click from the relay that Q2004 is controlling, which activates the main power transformer, but got nothing.
You could put 3.3V or more (see below) on the Power (1) PRY pin (W2505) as long as the cable is disconnected from the connector (so it can't back feed to whatever is driving it). Q2004 base current is limited by R2050 (page 139) i.e. it's not critical although it's best not to go lower than the original 2.7V or higher than say 5.5V. The Power (1) board has got mains potential so please be careful.
To check that RL201 is operating, I can think of a couple of options:
1. You could measure Q2004's collector voltage which would also indirectly measure the relay coil voltage.
With PRY 0V, the Q2004 will be off & its collector voltage should be 5.5V (pulled up by the relay coil) & since both RL201's coil connections are at 5.5V, it will be de-energised (no current flowing through the coil). With PRY 3.3V or higher, it's collector voltage should drop to 0V i.e. one connection of RL201's coil will be at 5.5V and the other connection (Q2004's collector) will be 0V i.e. in theory, the relay will be energised.
2. Find a reasonably safe low voltage secondary and check it with a multimeter on the ACV range (must be on AC volts). The Video (2) board (page 142) has transformer secondaries on CB351, CB352 & Video (3) C351 (also on page 142).
Changing subjects, I assume the amplifier is still disassembled?
I had a think about this apparent loss of voltage to Q1096. In addition to R1009 (which frustratingly is OK & you confirmed it is definitely physically connected through to C1105), there's a couple of other possibilities:
1. R1280 - a 5K6 resistor on Q1096's collector, could you check if it's open circuit? If it's open, Q1096 won't get power & it also won't turn on Q1009.
2. Q1009 - check for the base - emitter diode (& might as well check for base - collector diode). If B-E open same story Q1096 won't get enough power.
Hopefully, Murphy will be kind... I'm off to bed.