Sometimes the scalers get in a bad state and return -1 in some channels. You can figure out which crate has the problem by looking for -1 (or otherwise bogus) data in the xscalers displays, or watch the HALOG for a new entry titled "SCALER = -1". See which crate has the for red highlighted '-1's in that entry.
This state (-1) in the scalers is cleared by power cycling either
- TS12 crate for the BigBite scaler (use hareboot30), and/or
- TS11 crate for the L-HRS scalers (use crate reset screen from top-right corner of HallA Tools window).
Sometimes they need to be power cycled twice to really clear all the scalers from bad(-1) state.