I was able to get a much better image by injecting a composite signal into the grid of the 1st video amp.
Injecting an IF signal into each of the four IF stages seemed to produce a good image as well. I say seem because it's possibly my injected signal was larger in amplitude than a normal signal would be.
Also tried driving the AGC bus directly with a variable DC power supply but it really didn't do much. If I went slightly above or below 0 volts, the image would disappear. Schematic shows 0.1 volts on the AGC bus during normal operation. I'm really not sure what the normal range of this voltage should be.
Finally, went over the tuner again but didn't find any issues.
