I don't have a 465 but I briefly looked at the power supply schematic on sheet <12>.
Started trying to determine the possible issue and determined that I had noIf this is the +22V at pin 8, it is needed for both 55V and 15V regulators.
So continued on going thru the +55 regulator andThis would disconnect +55V regulator feedback loop, without the feedback loop I expect +55V to rise to an out of spec voltage (not safe). I don't recommend disconnecting pin 1. I can't easily explain why +22V would show up, may be R1524 now supplies more current (see below).
So then re-socketed the pin 1 along with all others and it would dropWhat was the voltage at +22V when you disconnected pin 7? If it recovered to +22V you have either a short in +15V supply or a bad transistor Q1548. This is the theory of what is happening: If output of U1524B is pulled to ground it takes current from its supply (pin 8) which comes from +22V. This voltage is generated by R1524/VR1526 shunt regulator. It can't supply current above (55V-22V)/4.7k=7mA without going out of regulation.
Traced it down to the Q1544 transistor when it was removed the U1524 amplifier voltagesRemoving Q1544 cuts the current to +15V and also turns off Q1548. The issue still points to either a shorted +15V or bad Q1548. Lead 6 of U1524B is +15V supply, without Q1544 +15V can't regulate so it is normal to have lead 6 ~ 0V in this condition.
Swapped it out the Q1544 with no change. So now if II assume in this state +15V TP is ~ 0V
Thinking that the Q1546 isI also think you are looking at the correct area.
When everything is connected, what voltages do you see:
At 15V TP
At the emitter of Q1546
At the base of Q1546
pin 7 of U1524B
base of Q1548B
Voltage across R1549 (this tells us how much current is pulled from Q1546).
We are looking for a possible high current out of U1524B pin 7 (~ 10mA).