Doug and Tavi on shift.
Noticed that the CODA event sizes were too large (~4500). Looked at
xcefdmp and determined it was right WC TDC slots 14, 16, 18 which were
generating 256 hits (limit) per event. Usually this means that the
thresholds to the amp/disc cards is not on. However, access to south hall
showed power was on. Cycled power just for fun anyway.
Problem still present, strange that it affected only TDC slots 14, 16, and
18, and not 20, 22, or 24. Possible problem with TDC's? Fastbus? Cycled
power to Fastbus crates.
Problem still present. Phoned Karen for advice. No other ideas.
Hall access to measure voltages on output and on WC. All okay. Decided to
reboot EPICS crate which controls thresholds. Crate did not reboot
successfully. One of the 4514A (DAC's) indicated a fault. Noticed that
the fans were not working and that the cards were very hot. This 4514A unit
controls the thresholds and the pressure readout of the chamber gas system.
Gas system went into alarm and closed valves.
Louis from CCR found spare 4514A so we replaced this. Unfortunately I was
too stupid to realise that one needed to set the slot address on the 4514A
using jumpers on the inside of the unit so it didn't work.
Gave up and turned the beam over to CCR for tuning.
In morning Adam set the jumpers properly and the 4514A worked and
everything came back.
Townsend replaced the fans in the crate but also noticed that the fans in
the rack are blowing into the rack rather than out of the rack which should
be fixed at some point.
I replaced the amp/disc cards in R11 and R29 to see if this is the problem
with missing data from these two boxes. Need beam to verify.
Runs 1242 - 1250 junk as these were all tests with high event rates.
Cheers,
Douglas
26-415 M.I.T. Tel: +1 617 258 7199
77 Massachusetts Avenue Fax: +1 617 258 5440
Cambridge, MA 02139, USA E-mail: hasell@mit.edu
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