Level translator card power supply voltages were also fine.
Kalyan checked the output of a level translator card on chamber 3: it showed a regular oscillation with a period of 125ns and a pulse width of 25ns. The equivalent output for a chamber 1 card was clean (as it should be).
Since raising the threshold voltage for chambers 2 and 3 gets rid of the oscillation the problem seems to originate at the A/D cards. However, the supplies voltages are all good -- damned if I know what to check next...
We will raise the thresholds on chambers 2 and 3 to get rid of the
symptom and continue with the program. Need more ideas from experts for
A copy of this log entry has been emailed to: xqian