Thanks for the reply, Chuck!
Here are the power supply voltages and ripples, as measured at J119:
-15 measures -15.001 V with 0.99 mV of ripple
+5 measures +4.991 V with 33.86 mV of ripple
-15 UNREG measures -18.293 V with 28.1 mV of ripple
+10 REF measures +10.009 V with 1.34 mV of ripple
-5 measures -2.899 V with 8.71 mV of ripple <<
+15 measures +15.010 V with 0.58 mV of ripple
+87 measures -+86.799 V with 1.08 mV of ripple
+42 measures +42.484 V with 1.10 mV of ripple
-8 measures -4.291 V with 30.4 mV of ripple <<
+5 measures +4.978 V with 0.96 mV of ripple
So clearly there is something wrong with the -5 and -8 supplies. I measured the unregulated output of the -8 supply at J232A Pin 5 (interconnect between the A3 and A2A1 boards), and it was -8.3. When I removed the interconnect, the voltage jumped up to -16.5.
Is it reasonable to assume that the problem may well be with the filter capacitors on the A2A1 board? I suspect that a shorted or leaky C1350 may be pulling down the -8 line, and thereby pulling down the -5 line through CR1334.
The next step is to remove the LVPS. I plan to do that later today.
Thanks,
Stan
