FID base signal has become lower and lower, so lit offset had to be set to 0. The flame ignites but the signal is in the negative values and teh baseline is totally flat: peaks are detected, but the baseline is cut off because in teh negative.
Could it be the FID board that needs to be changed, or is there some way to offset the basleine higher so it does not go into negative?
The instrument is a 7890A
