As most of you know, starting from the end of January, we had a serious
jitter problem in LED/TDC calibration for SM4.
Looking at today's laser calibration data, we noticed a similar jitter
on ERP-ADC vs Ref-ADC plots in the same SM. This suggested us to check
out something around ERP stuff.
In fact, we found a 50Hz AC component (+6V line) in ERP trigger crate
power supply. After having replaced it, the problem DISAPPEARED!!
In addition, during the operation, we replaced a broken LEMO connector
from the fakebox fan-out channel on the same SM.
A presto,
Nicola, Massimo & Roberto