Evening Shift, Monday, August 26, 2002 16:00 Shift begins. Mark Ito & Dan Dale finish discussion of how to log the run configuration. Mark heads to MCC to ask about beam possibilities. 16:25 Mark reports from MCC. They're testing software and don't project beam for the immediate future. 19:05 MCC calls and reports software failure. Apparently they'll be going back to what worked yesterday, but it'll be 2-3 more hours before the halls get beam. 20:05 Valery is looking on HyCal histograms. See multiple peaks. Turned off sparcification on HyCal ADCs. On Valery's request Yar went down to the hall to increase LMS frequency. 20:45 Valery and Yury went down the hall to check HyCal signals, gate timing and trigger circuit. 21:55 Dave came and went down the hall for HyCal troubleshooting. 22:38 D. Lawrence - Valery and Yury found that ADC gate timing was shifting around by 128ns. This was a constant shift that occurred on half of the events. The problem was traced to a conspiracy of the following: The threshold for all strips was lowered last week to 50 mV. The large pulses added from many detectors due to LMS were causing multiple pulses from the UVA125A discriminators. Often 2 and occasionally 3 pulses came from the UVA125A. The TS prescale factor for the HYCAL trigger was set to "1" which apparently means skip every other event. The gate timing was then set by the first UVA125A pulse, until it sent an odd number of pulses (either 1 or 3) which caused the timing to be set by the second pulse due to the prescaling. The threshold on the UVA125A modules was raisd to 106mV and the prescale factor set to "0". The second pulses from the UVA125A's are now gone and the gate timing is constant and occurring for every event. 23:08 MCC calls & informs us they'll attempt to give us beam. 23:20 Beam's here but at least 1 mm off in X Position. 24:00 Shift ends. Beam's still constant energy but >2 mm off.