Ok pin 14 should be -16v and pin 12 should be +16v. They cannot swap. So check you had you black lead on pin 13 all the time you were testing. But looks like you are missing the +16v rail form the rack power supply.
So remove everything from your 500 rack and check at the edge connector inside the rack that you have +16v at pin 12 and -16v at pin 14 when measured from pin 13 PWR GND 0v. See attachment.
Empty rack power supply test.
black lead pin 13.
Red lead to
pin 12 = ?
pin 14 = ?
Hi Joe, I tested the edge connector again (several times). I get 0V on pin 12 and -16V on pin 14.
When I tested the rack power supply by itself I get +16V on pin 12 and -16V on pin 14