What does AGC DIP switch on Kramer FC-400 do?
 

1. If using Kramer format converter fc-400 for its framesync properties should I turn dip switch three which is the agc on or off for best picture when using the device as s-video PAL in to s-video PAL out mode?

2. What does the so called automatic gain circuit (agc) do?

3. During what circumstances should agc be turned off or on?
I would like to speculate thoroughly if possible like format conversion utilized or PAL, NTSC, s-video or composite input/output benefits more/less, tape degradation capture equipment etc.