HV History, Run 1999 - 2000
: M4, card 6 and M2 card 10 are replaced; M4 cards 0
and 1 has intermittent problems; M5 card 9 ch 0 has AV lower than DV.
1/20/00 : M3, card 0, ch 7 has
50 V AV less than DV.
1/24/00 : M3 controller
not working; two different replacement controllers from PREP are tried,
also not working. After checking that the controller from another mainframe
(M4) works fine, the original controller is reinstalled, and after touching
the potentiometer that sets the maximum HV output M3 controller starts
1/27/00 : M6, card 0 is replaced.
The 128 V bit is found to be always on in M2 cards. M2 controller
3/15/00 : M3, card 12, ch 2,3,4,12
has DV=AV-60V. The card is replaced. M1 card 0 ch 0 (H1-1) has AV <
DV by 72 V; this discrepancy disappears after power cycling the mainframes.
3/14/00 : M4, card 6, ch 12
has AV=DV+200V. Card replaced.
4/4/00 : M5 turns itself off
during run 5406.
4/15/00 : reported problems
with M2; affected
run 5491, which is stopped
because of this. After power cycling the mainframes the problem disappears
and run 5492 is started.
5/1/00 : during the last 20-30
min. of run 5581 M2 turns off all cards. The
controller keeps turning off the cards after 5-10 min. after turning on
the mainframe. After changing the controller the problem disappears.
5/4/00 : run
5608 is terminated because M6, card 11, sets off the
HV alarm; it is found delivering AV lower than DV by 700 V to 900 V.
The last 15 min of run 5608 are affected by
this problem. There is no apparent pattern in the difference between AV
and DV, or AV alone, so the card alone is checked first, but this doesn't
solve the problem. Changing the controller puts things back in place.
M = mainframe
AV = Actual Voltage; it is the voltage read by the ADC
on the HV card for each channel.
DV = Demand Voltage; it is the requested voltage set
using the HV control program.
BV = Backup Voltage; voltage value loaded into the backup
buffer with the HV control program.
modified: Tue Apr 18 15:27:16 CDT 2000