The following readback channels of the CLF and OPO ISS servos are saturated: SQZ-OPO_ISS_ERR_OUT, SQZ-OPO_ISS_CTRL_OUT, and SQZ-CLF_ISS_ERR_OUT. The only one working is SQZ-CLF_ISS_CTRL_OUT. However, comparing this channel with the corresponding slow readacks, it looks like this is actually the OPO readback.
The working CTRL output shows roughly twice what the slow monitor indicates, so this may explain what the other one saturates.
The ERR readbacks may saturate because none of the boost filters are engaged.
The DAQ readback cables were swapped at the remote rack. Fixed now.
The discrepancy in the DAQ control readbacks was traced to a missing 18.7K resistor, R197, in D1900049.
The fixed spare unit, S1900202, has been installed at the CLF ISS location.
The fixed CLF ISS units, S1900203, was then installed at the OPO ISS location.
Finally, the fixed OPO ISS, S2100110, has now become our spare.
Transfer function of whitening filter in fixed DAQ readback.