I dove a bit further into the H1:TCS-ITMX_CO2_ISS_CTRL2_OUT_DQ channel correlating with our range drops on some days in May (alog78089). Robert and I also went onto the TCSX table and confirmed that the AOM is unplugged and that there were no other obvious culprits there on table. I added a 50 Ohm BNC terminator to the AOM as an excissive precaution and also moved some of the disconnected BNC cables on top of other cables to keep them from contacting the table directly. We also got Fil and had him look in the CER at the related chassis just in case.

Shown in the attached screen shot, the channel in question is ahead of an open switch (#1 & #2 are the CTRL2 outputs shown in medm and the electronics drawing - D1300015). #3&4 are the switch and #5&6 are the CTRL1 which doesn't see this same noise that CTRL2 sees during the range drops. The source of the extra noise must somehow be introduced somewhere from the open switch to the CTRL2 channel. In epics, I only see it in the CTRL2 channel. Interstingly, on May 17 the TCSX laser lost lock and the CTRL2 channel had an odd glitch 4 seonds before (2nd attachment).

Talking with Fil we might try disconnecting some of this at the AA chassis or swapping with TCSY to see if the problem moves with the chassis. In favor of not losing the one channel we have that connects some of our range loss, we might try swapping the chassis first.