Watch history qod for any sudden increase in DC or PC hit multiplicity. History qod of these is here
As twistonl, go to ~/online_anal directory and run the script: plotsplitrun.csh 17828, where for 17828 you put the run number which has this high multiplicity.
Look at the first page of histograms that the above script gives you from the directory ~/online_anal/ps/*17828*.ps.gz. On this first page look at the wire number vs plane wire hit distributions. If all of the planes look normal (no plane which is all lit up) then there is some other problem. Otherwise make a note of which plane you need to stop from oscillating. An example of what oscillation in plane 24 looked like on this page of histograms is posted as an elog here.
From the status bar open the postamp Tcl panel, then click on the detector button to get the post amps by plane. Then for the plane that you want to stop from oscillating, click on the bottom postamp box, then click on the "dth" number, then set this value to 500mV. Do this for every other postamp box on this plane. Then to set the thresholds, click on set hardware, then select set changed.
Take a run and check that the oscillation problem is gone, then reset the threshold to 150mV following the instructions in the previous paragraph.
Take a run again and verify that the problem is still gone. If the problem persists, we may have to follow the above procedure, but only lower the threshold to 175mV.
When you are done with the postamp panel, click Exit button. Do not push the window's cross since this will leave a process running in the background.