I have not had any exposure to the newer ACI module but have heard good comments from system techs that have used them. They were using them in Gainmaker and some GI gear.
The SA II and SAIII amplifiers have historically had poor grounding problems and the AGC was not very good for this reason. That is one of the main reasons that SA went to a metalic cover to isolate the components. This metalic cover also had its problems since technicians would either remove it, strip out the screw inserts and leave the screws either missing or loose. Any of these issues would cause a severe RF isolation problem that was directly related to a bad response and cause intermittent suckouts and unstable pilot frequency carrier reference. This in turn would not keep the AGC stable in a quick explaination. With the housing cover open you would get a different response compared to it closed.
Bottom line, no matter whose AGC module you use, if the RF grounding for this module is poor and the metalic cover is loose or missing, do not expect it to operate correctly to the manufacturer specifications. The SA/Cisco Gainmaker is a totally different beast as it has superior RF grounding and the AGC is not effected as were the SAII and SAIII units.
Another issue with the SAII and SAIII is CONFIRMING that you have correct interstage attenuation that matches the internal 9dB required insertion loss. Example: If you use an SA AGC module (9dB insertion loss) you need a 0Db (zero dB insertion loss) attenuation pad for the interstage. If you are using a SA Thermal Interstage Equalizer (4dB insertion loss) you would instal a 5dB attenuator pad to equal the 9dB interstage insertion loss. Keeping the 9dB interstage loss constant does two things. First, it maintains the amplifiers designed GAIN and second, it allows the AGC pilot to have a correct window to operate from. *NOTE* - It is up to the system technicians to keep the frequency response "flat" within specifications to correctly operate with unity gain through a system SWEEP.
If you have any questions about that old SA gear please ask. I was an Applications Engineer for Scientific-Atlanta in the "Good 'ol Days"!
Good luck!
