Yesterday I tinkered with this unit for most of the day to try understanding the problem.
I tried cleaning/re-seating the ribbon cable connector, re-soldered all the connections on the display board, and even one of the FPGAs.
It seemed the display was working better when I injected 15MHz (prior it was showing dollar signs), but noticed one segment on the far right digit was always on. It looked good for things like 3,4, etc... but when it displayed '1', the bottom right was still on. Eventually I noticed it began displaying dollar signs again, but didn't seem to be frequency dependent.
Also, when I decrease my input frequency to somewhere around 100Hz, the counter froze. I need to confirm my generator isn't the issue at low frequencies, but it's obvious my counter isn't functioning correctly.
To summarize: it has the far right bottom right (segment C if I am correct) always on, displays (what appears to be) dollar signs in some cases, doesn't measure low frequencies, and misspells AUTO TRIG (it shows AUTOOTRIG).
Is this a case where updating the firmware may solve the problem?