Why not video AGC in the TRK12?

[dtvmcdonald]

I've got a question about the TRK-12!

Why did they apparently remove the video AGC system from the sets
in later production? My chassis obviously had at one time had AGC but it
was chopped out. (This chassis was used as some sort of engineering test bed.)

Was it impulse noise? I note that VRAT in England has been having
a discussion about that for the British 405 line (white is higher modulation,
reverse of ours) system. I understand the difficulties of AGC in the 405 line
system, but not in ours ... the original TRK12 schematic is exactly as I would expect
a non-gated AGC to be, that is, first the video detector which is an averaging
detector (for the RF) followed by a second diode used as a capacitive input
rectifier with long time constant, acting as a peak detector on the video.

Why drop AGC?