Ah ha. (GREAT job on the readings, I was able to jump right in!!)
the awr-031 board is performing correctly. Feeding the raw voltages to the awr-032 regulators.
AWR-032
1) 0V this is ok
2) 898mV bad, should be -16v but can be ok if -42v is fixed AND the -24v is working.
3) 430mV bad, should be -24v but can be ok if -42v is fixed
4) -1.74V bad, should be -13v but can be ok if -42v is fixed
5) -3.22V bad, should be -42v here is the start of the problem,
but this problem masks whether the rest of the negative regulators are working
(pin 4 = -13v, pin 5 = -42v, pin 3 =-24v, pin 2 = -16v)
6) -60.1V this is ok, the negative regulators are being fed properly
7) 59.2V this is ok, the positive regulators are being fed properly
8) 43.4V this is ok
9) 36V this is ok
10) 25.6V this is ok
11) 17V this is ok
Thus Q2 2sb507 and Q4 2sa720 are suspect and one or both is falling down on the job.
Q2 "makes" the master -42v, that feeds the -13, -24 and -16v regulators.
So the other regulators can't be checked until the -42v is present again.
We can go a step further and read / post the three each (e,c,b) Q2 and Q4 voltages, or replace just q2 and q4.
R4 is part of a low current power feed to operate the regulator. IF it looks crispy the regulator failure took it out and it should be replaced.
HERE'S the catch: WHY is the -42v busted? did a problem with one of the OTHER voltages take it out with an overload? pins 2 and 3 with POSITIVE millivolts makes me a wee bit suspicious.
we could fix it, only to have it fail again. just preparing you...
This is for educational purposes for the "gallery".
R2 / C2 form a ripple rejection filter, to power the regulator with CLEAN dc - ANY AC will go right through the regulator - that's why the JFET constant current source (and the EchoWars constant current source for the higher voltage on the SX-1980) is used, instead of relying on brute force filtering with a HONKING BIG CAP to get the hum out like this typical Pioneer regulator does, the circuits supplying the constant current reject the hum. In another high end Pioneer amp (class a power amp?) I saw a full blown current source circuit implemented with a transistor and resistors.