I bought one used cti CB6580 amp board and some 6230 motors of ebay recently. I want to build a pair of scan amps to drive my 6230's using the CB6580 as a starting point. I am trying to wrap my head around the AGC circuit. Is it totally necessary for projection use? It would seem that an adjustable current source driving the PD led would do the same thing but with less accuracy. Also, looking at the schematic R19 is not labeled but is 10ohms on the board. This seems odd because if transistor Q1 fails or the opamp driving it fails it would burn out the PD led.
thanks for any input.