Subject: still problems on SM4
Nicola.Zaccheo@lngs.infn.it
Date: Thu Aug 31 2000 - 11:31:42 EDT
Ciao a tutti,
this night run 19883 stalled. Yiannis restarted a PHRASE run only
from the USA. This morning I again found the Kinetic 1500 power
supply on B:2,C:4 (SM4) w/o all the positive voltages. Checking
the positive voltage regulator card, I found a 10Ohm resistor (R9
in the schematic) fused(!). I replaced it, I tested the power supply
(with 3A and 4A load) and it was O.K., then I put back it on the crate.
When I turned it on, after loading the CAMAC list, the West/East TOHM
attico module had all the red and green LEDs (act-0, act-1 and trigger)
of channels 7 and 11 stuck, even if I unplugged the input signals (note
that no signals were present from the trigger output and that the power
supply continued to work fine). Furthermore, it was impossible to select
channels from the key on the front-panel of the module. I removed this
module, I checked it w/o finding anything of trivial, then I put it back
on the crate...no red lights lighted (the channel select still didn't work).
I performed a mini-acq for more than 1hr (1000 events) and, analysing
the data, all the SM4 TOHM attico west channels were died while all the
SM4 TOHM attico east ones had the same high trigger rate (~80mHz)..
At this point I touched the TOHM module and then *all* the LEDs lighted...
I don't know if the power supply breaking caused the module breaking or
'viceversa'...there is something of strange on the electrical power on
the SM4 (problems for the streamer tubes there, fire-alarm Saturday night,
the uVax2 VT420 terminal found broken yesterday...)
at this point I prepared a CAMAC list in which I excluded the TOHM West/East
attico and, after testing it, I started a new run (I tried to contact Sophia
to hask her suggestions w/o success) that is, for the moment, w/o TOHM
West/East Attico on SM4..
(It's better to run w/o TOHM W/E on SM4 that w/o the full uVax2)
Let me know your suggestions.
Nicola
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