OK, here are results for your reference:
200.1 - AD_IN = 0.044 mV, Pin.2 of U322 = -0.012mV, REF (pin.1 AD board) = -10.2893V
all othe 200.x tests about same voltages, so it's mostly internal test on A/D board using U80x registers and CPLD.
Check you voltage supplies (+15,-15,+5) to make sure they are not noisy. If I artifically cause shift on VREF even 0.1mV - test will fail.
201.1 = 0.137mV, SCOM = 3.491mV, pin2 u322 = -0.020mV, REF = -10.28967V, pin.6 U322 = -8.467mV
201.2 = 6.88303V, SCOM = 3.484mV, pin2 = 6.88364V, REF = -10.2897V, pin.6 U322 = +7.994V
201.3 = 1.72111V, SCOM = 3.489mV, 1.72094V, -10.2897V, pin.6 U322 = +1.9922V
All measurements taken relative to black wire LO terminal. I have about 8mV pk-pk noise on +15V, 3mV pk-pk on -15V, 12mV pk-pk on +5V going to A/D board, measured by other 2001 using VAC PEAK mode.