J. Kissel, H. Radkins, R. McCarthy

We tried a few things in order to debug STS B (GND_ITMY), which had been revealed to have a factor-of-2 too low gain after an event at Tuesday, 8:30a Dec 23 2014 (see LHO aLOG 16237). Nothing was successful at fixing the problem. However, we have ruled out the STS Distribution Chassis, the STS Interface Chassis, and the ADC that reads in the STS by swapping a few cables around at the rack: 
- The factor of two followed the field cabling, i.e. when STSB / ITMY was plugged into STSA / HAM2's readout, the factor-of-two moved to STSA / HAM2 readout. 
- Richard also made sure that cables were secure both going in and out of the satellite amplifier. 
- Finally, he injected (differential) +10 [V_{DC}] into the appropriate STS Interface Chassis channel, and found the readout displaying +16384 [ct], as expected (see T1100538). 
This implies that the fault is either in the STS itself, the orange cable from the STS to its satellite amplifier, the satellite amplifier itself, or in the long cable run from the satellite box to the racks. 

Richard suspects that the custom D50 connection at the STS Interface Chassis, but will continue to investigate tomorrow.

Attached is evidence of the mornings activities, but more importantly that the gain factor is *exactly* what is was before after restoring everything, so we'll continue to use the matched gains determined in LHO aLOG 16208.