Reports until 15:20, Friday 10 March 2023
H1 SUS (CDS, SUS)
rahul.kumar@LIGO.ORG - posted 15:20, Friday 10 March 2023 - last comment - 14:50, Monday 20 March 2023(67899)
ETMX ESD low voltage interface chassis replaced

Fil, Camilla, Gabriele, Rahul

While investigating the ALS_DIFF issue (due to which we were unable to lock the IFO since Tuesday night - see alog 67875) Camilla and Gabriele found that the ETMX ESDLV MONs have been stuck at 24V since Tuesday. We tried toggling ON/OFF button for the Hi/Low voltage on each quadrant from the medm screen (SUS_CUST_QUAD_BIO) however nothing changed.

Fil and I then went to the End X station and power cycled the ESD drivers and IO chassis, without any luck. Fil spotted that the +15V light on the low voltage interface chassis was not ON (which was not a good sign). We power cycled that as well and it worked for a min and then went bad. We then decided to replace the faulty low voltage interface chassis with a new one after filing a work permit (11056), while SUS ETMX was put in SAFE state. We carefully re-connected all the cables in the new chassis, powered it ON and checked for grounding issues using multi meter and found no issues. On the ETMX medm screen we cross checked the ESD power supply by toggling it on/off and it worked fine.

Given below are the s/n of the old and new chassis

ESD low voltage interface chasiss 

s/n S15000730 (old)

S/N S1500070 (new)

WP 11056 closed.

We are now able to lock the IFO with 60W input power.

Comments related to this report
jeffrey.kissel@LIGO.ORG - 09:41, Monday 20 March 2023 (68064)CAL, DetChar
Link 

Tagging CAL.

Note there's a typo in the call out of serial numbers:
S/N S1500073 (old)

S/N S1500070 (new)

And it's also worth calling out here what was revealed in the S1500073 e-Traveler, that -- post-mortem -- the failure was found to be
    Bad crimp found on power switch connector on positive 18V rail.
rahul.kumar@LIGO.ORG - 14:50, Monday 20 March 2023 (68075)
Link

FRS ticket 27320 filed.