HV History, Run 1999 - 2000

• 12/14/99 :   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 working fine.

• 1/27/00 : M6, card 0 is replaced. The 128 V bit is found to be always on in M2 cards.  M2 controller is replaced.

• 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.