Some of the ARS channels had the first sample to zero, creating TDC histograms at zero for every event.
This may be solved by reseting the ARS (after stopping the current run, do abort, download, start run in the CODA run control).
In any case this is not a big problem. I modified the gui to show TDC spectra between 5 and 123 ns. If this run is reanalized, it should now show correct TDCs.