Quote:
Pin 53 of the Strongarm goes high and low as it should


I believe that (pin 53) is all that is necessary for this stuff to work.

The player s/w uses pin 53 to detect AC/DC. So if you see the player thinking "AC" when it's really on "DC" (or the other way round), and pin 53 has been verified to be getting the correct levels, then that input on the SA1100 is probably fried.

Just to recap: is that the actual problem here: player uses DC when on AC (or vice-versa)?

??