LIGO Document D1600122-v3
- The main circuit board containing the drive electronics, filtering, and switching functions for the ITM ESD drive system.
- Version 2 of this is a schematic change. The version 1 PCB is still unchanged (although it needs changes for future orders). A summary of schematic changes and jumpers added is as follows:
1. Found a miswiring between the Pole-zero DC outputs and the individual quadrants. Corrected by jumpers on board. Schematic is now correct, but future revisions of the PCB must be changed.
2. Found the relays on the Pole-zero stage are miswired. Corrected with jumpers on the board. Schematic now correct, but PCB must be updated for future revisions.
3. Corrected typos on page numbers and sheet titles
4. The miswiring on the LF DC relays produces an unfortunate readback logic situation. The normal state of the relay is reported as 0V which might lead to confusion if the cable were not connected.
5. Saw a slight microphonic tendency in the HV circuitry while at 400V out. Cause as yet unknown.
1. Changed C27 from 4.7pF to 33pF in response to a 230kHz oscillation found on the HV bias amplifier
2. It is possible that some of the microphonic tendency was due to the oscillation seen in the HV bias amplifier.
DCC Version 3.4.0, contact