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    User name R. Michaels

    Log entry time 11:43:21 on June11,2001

    Entry number 62871

    This entry is a followup to: 62444

    keyword=L-arm T1 scaling fixed

    It was noticed for a few days (halog 62444) that the L-arm copy
    of the trigger 1 (T1) signal was over-counting. In today's access
    it was found that a Phillips 757 logic fanout on R-arm produced an
    after-pulse of 135 mV 20 nsec after trailing edge; this was sent to L-arm
    and was apparently enough to fire logic modules there (with some
    probability). Solution was to avoid the 757 and instead use a LeCroy
    623B discriminator with 210 mV threshold as a logic fanout.

    I don't think there are any serious implications for experiment, as both
    the R-arm scaling and the R-arm trigger supervisor T1 signals looked ok.
    All other scaling and TS signals were checked on scope today. Ringing
    is less than 30 mV.