Reports until 18:35, Tuesday 25 September 2012
H1 SEI
hugo.paris@LIGO.ORG - posted 18:35, Tuesday 25 September 2012 (4296)
HAM2-ISI - CPS-H1 railed readout

Dave, Hugo,

Sometime around 4.30pm today, HAM2-CPS-H1 showed ~ +32000cts. The Watchdogs were then tripped. We turned off the master switch on the medm screen and the coil-drivers electronics, the readouts remained the same.

Dave and I restarted the h1iopseih23 and the computer/frontend. No change.

Connecting the faulty channel on another sensor interface showed that the signal was following the channel.

I went upstream and checked the voltage outputted by the ADE box of the CPSs: 

-over 13V for this sensor.

-Within +/- 1V for the other ones

I tried connecting CPS-H1 on its neighboring ADE board. I also tried swapping the FeedThrough-to-ADE in-air cables between H1 and V1. 
The readout of CPS-H1 came back to normal during this process. It seems like the in-air FeedThrough-to-ADE cable of HAM2-CPS-H1 is faulty. I left it ON keeping in mind the symptoms we saw.