Subject: ERP problems on SM3
Nicola.Zaccheo@lngs.infn.it
Date: Fri Sep 29 2000 - 05:23:03 EDT
Ciao a tutti,
during run19971 the +/-12V VME power supply on ERP SM3 broke.
After its replacing with the (last) spare (that has a bad AC ripple
on -12V -> 120mV, ~2KHz), there were still problems because the S/H modules
lost power (with all the voltages present on the VME crate!) when a
operation occured between the VME crate and the ERP supervisor via the
ribbon cable. We replaced the ERP supervisor with the only spare available
(labelled as good!) but the problems was persisting.
After a lot of work, I discovered that the spare module was broken too!!!
In fact, using the one working on the SM4 everything went fine.
So, the SM3 ERP supervisor modules and the spare one had similar problems.
Note that nothing of trivial (broken ufuses, etc..) was present on these
modules..
We decided to use the North face supervisor module on ERP SM3..So, starting
from run 19978, there are nolonger ERP triggers on the North face!!!
With the new hardware, ther are *NO* problems on ERP-mu trigger rates,
but there is a *high* ERP-GC rates, expecially for 3E13 and 3E14:
during the last run, there were ~ 14700 counts/hrs instead of
previous 5293 counts/hrs on SM3 ERP-GC..the last run duration was 8.94 hrs.
instead of previus ~ 9.18hrs (maybe there is the need of a new LUT iteration)
A presto,
Nicola
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