I tried to run L1.1 trigger and look on RS TDC DYC light to find about patterns of errors. I suspect that this problem is not DYC or TDC specific. George, I'm not sure if I've chosen the right combinations of triggers + SSP, but anyway: 1. Reference combo (supposed to work and did work) kp21 + all_v2 2. Testing combination (where RS TDC hung the system): kp22 + cs1_noCCD Next I represent a table of LED states when DI got stuck, or sometimes when DAQ was running but something clearly went wrong. All the lights combinations are either between spills or when DAQ got stuck. It usually takes about 10 spills to hung the system with kp22 trigger. DYC1 DYC2 DYC3 DYC4 DYC5 DYC6 .............................................................. Normal work prmt empty empty prmt empty empty between spills empty empty .............................................................. Got stuck prmt empty empty empty prmt empty kp22 empty empty .............................................................. Got stuck prmt empty empty prmt empty empty kp22 empty empty .............................................................. Got stuck prmt empty empty empty empty prmt kp22 empty empty .............................................................. Got stuck prmt NONE NONE datain prmt datain kp22 empty empty full .............................................................. Got stuck prmt NONE NONE prmt empty empty kp22 empty empty .............................................................. Got stuck prmt empty empty prmt empty empty kp22 empty empty .............................................................. DURING run prmt empty empty empty prmt empty kp22 empty empty this combo flashed 3 times while taking data and after that recovered into normal one .............................................................. Got stuck prmt empty empty prmt empty empty kp22 empty empty .............................................................. DURING run prmt NONE NONE prmt NONE NONE kp22 empty empty this combo flashed 4 times while taking data and after that got stuck with the same pattern .............................................................. Got stuck prmt NONE NONE prmt empty empty kp22 empty empty When taking kp21 LED patterns were alway right, though sometimes DAQ got stuck with the error message about not being able to readout cable segment-1. 1. There is a whole variety of errors. 2. It does not seem to be a particular DYC or DYC chain. Sasha.