aLIGO LHO Logbook

H1 ISC

stefan.ballmer@LIGO.ORG - posted 17:11, Thursday 03 November 2016 - last comment - 11:01, Friday 04 November 2016(31181)

POPAIR_B_90 demodulator LO input broken

Over the last couple of days we noticed the POPAIR_B_90 was randonly jumping up and down.

Further investigating this, we found that just touching the SMA connector of the 90MHz LO of the POPAIR_B_90 demodulator box, the phase jumps by easily 90deg.

Smells like that LO input is broken - but we'd have to take the chassis out to fix it.

Comments related to this report

richard.mccarthy@LIGO.ORG - 11:01, Friday 04 November 2016 (31199)SYS

Link

Found the SMA connectors to be over tight.  I could not remove them with out pliers.   The SMA insulating sleeves were in bad shape.  The filter for 90MHz was not seated properly.  Re-seated the filter,  Change the rear panel with a new one.  Made sure all of the connector inside the chassis were torqued properly.  Re-installed chassis.
Fault report 6599
https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=6599

While in the LVE re-torqued all the SMA connections in the racks by the PSL.  There were a number of loose ones.  (AGAIN)

We have a torque wrench lets use it.