Teledyne LeCroy DXC100A - Manual (Page 18)

DXC100A Differential Probe Pair
16 922259-00 Rev A
When the +probe has been properly adjusted it should be used as a reference.
CMRR adjustments made to the probe in the future should be done to the –
probe.
At this point, do not change any of the +Input X10 or +Input X100 Adjustments,
as doing so may require repeating the entire probe calibration procedure.
Figure 1, The DXC100A Board Layout