With Yasui-san and Hirata-san.
We finished assessing the health of the in-vacuum cables. The errors we found are the following:
- BF picomotors:
- Place: flange 1, connector 7.
- Pins: 1, 6.
- Symptom: The capacitance of the picomotor was 40 pF instead of the expected value of around 190 nF.
- Consequence: This is not expected to be a problem. None of these picomotors controls the orientation of the IM. Actually, we never use them.
- BF GAS LVDT:
- Place: flange 4, connector 3.
- Pins: 5 and chamber.
- Symptom: A resistance value of 12.4 Ω was measured where no connection was expected.
- Consequence: This is not expected to be a problem because pin 5 is the shield of the cable which is connected to ground when the in-air cable is connected. This symptom does not necessarily imply that the cable is damaged because the shield is exposed at the connectors and it might be simply touching the security structure.
- TM-H4 (coil in RM):
- Place: flange 4, connector 4.
- Pins: 3, 5.
- Symptom: A resistance value of 2.2 Ω was measured where no connection was expected.
- Consequence: This is not expected to be a problem. The actuation coil is connected to pins 2 and 7, not to 3 or 5. There is nothing connected to pin 3 and pin 5 is connected to the shield of the cable.
In the spreadsheet there are some entries with the acronym NC, which stands for no connection, and other entries with NC* with an asterisk. The astrisk indicates that we measured the resistance with LCR-9183 and not with the multimeter CD772. The multimeter can measure resistances up to 40 MΩ whereas the LCR meter can measure up to 200 MΩ. Additionally, NC* means that the measured resistances were above 100 MΩ, tyically closer to 200 MΩ, but were not stable and were always varying. This situation is not expected to be a problem because the reistances are very high.
The only discrepancy we found in the usage of the LCR meter and the multimeter was in the measurement of the resitance between pin 2 (actuation coil) and the chamber in IM-V OSEM (flange 4, connector 1, entry shown in blue in the spreadsheet). The multimeter measured no connection, whereas the LCR meter measured 1.6 MΩ. The OSEM has been working fine, so we tend to trust the multimeter in this case. Later on the LCR meteter ran out of battery but I'm not sure it is related.