HV = -3.5kV.
The efficiency of U2 Plane is much worse than the others.
For V1 Plane, wire 336-352 (V2_lower card) is perhaps bad.
For V2 Plane, wire 48-64 (V20_upper card), wire 128 -144 (V15_upper card) are perhaps bad.
The history of replaced Mad cards can be found on entry 386876.
Figure 1
Figure 2
Figure 3