This is the compilation of the information of the four Type-B suspensions in a single worksheet.

I have been often confused on how a few people use the word summary, so I guess it's useful to say that a summary is "a short, clear description that gives the main facts or ideas about something" (Cambridge Dictionary).

The worksheet attached is a compilation only. A summary will follow after taking a look at the data.

With Yasui-san.

See SR2 notebook for notes: album SR2 Remedying work after O3.

Last week we finished assessing the health of the in-vacuum cables by measuring resistances, inductances and capacitances at the outer side of the flanges of the vacuum chambers. We had unexpected results and in this entry I report the reproducibility after a second (or third) measurement:

• SR2, IM-V3 OSEM, P3-3, pins 2-7:
  • Symptom: the measured resistance (24.5 Ohm)  is higher than the equivalent resistance in other OSEMs (~19 Ohm).
  • Reproducibility: we confirmed the initial assessment; during the measurement the value was not fluctuating.
  • Following steps: we should inspect inside of the chamber or try to find glitches in the actuation.
  • Difficulty: medium; the connecting points of the cable segments are accessible with relative ease.
• BS, F0 yaw stepper motor, P3-3, pins 2-7:
  • Symptom: the measured resistance (13.4 Ohm)  is higher than the equivalent resistance in SR3 (8.8 Ohm)
  • Reproducibility: we confirmed the assessment today in an initial measurement, but we found it's not stable.
  • Following step: open the chamber and check.
  • Difficulty: low; this motor and its cables are in the pre-isolator making them easily accessible.
  • Note: it seems SRM and SR2 F0 yaw stepper motors have a similar problem and we need to check.
• BS, F1 LVDT, P2-2:
  • Symptom: see klog entry 18191.
  • Reproducibility: we confimed by a third time there is a problem; some of the resistance values have changed since last week.
  • Following step: open the vacuum chamber and check.
  • Difficulty: possibly high becuase we don't have access to the F1 filter from the outside of the chamber.
• SRM, RM Coil TM-H1, P2-4:
  • Symptom: the coil has a connection to the chamber.
  • Reproducibility: reproducible and stable.
  • Following steps: medium; the connecting points of the cable segments are accessible with relative ease.
• SRM IP LVDTs: last week we also found that the primary and secondary coils are connected to each other's pins. We confirmed this situation today. These devices are at the pre-isolator and are easily accessible.

With Hirata-san.

We examined the in-vacuum cable for the F0 yaw stepper motor. The resistance of one of its coils was higher than expected (13.4 Ohm vs. 8.8 Ohm).

We identified the source of the problem: the pins connecting the stepper motor cables to the extension cable are not making good contact. We realized by moving them and seeing the resitance changing. The resistance value settled down to a good value (around 8 Ohm) but we need to check again.

With Hirata-san and Nakagaki-san.

After we changed the flip cable adapters in Type-B suspensions, we checked again the health of the cables by measuring capacitance, resistance and capacitance values. I compiled the results of the three suspensions in a single file to make comparison easy.

We found the following potential problems:

• BS F0 FR pins 2-7 (P2-5): the resistance value is 10.7 Ohm, which is  several Ohm higher than expected (e.g. 4.7 Ohm in SR2); the value was confirmed by Hirata-san and Nakagaki-san today.
• SR2 IM V3 OSEM pins 2-7 (P3-3): the resistance is 22.3 Ohm, which is higher than in others OSEMs (20.1 Ohm maximum); the value was confirmed by Hirata-san and Nakagaki-san today.

With Hirata-san.

In the BS F0 fishing rod in-vacuum cable, we checked the connections to pins 2 and 7, which had a larger resistance than expected (10.7 vs. 4.7 Ohm according to see klog 19503).

We shook the cable close to a connector on the IP table and the resistance varied a lot, even becoming an open circuit sometimes. After disconnecting and connecting the connector, the resistance became very stable. Then we realized a screw in the connector was loose. The role of such a screw is to push the pins of the connector into place, therefore, we assumed this was the problem. We tightened the screw and  measured the resistance again while shaking the cable. It was very stable at 5.2 Ohm.