Check continuity between LSPC2-A2 pin 23 and both RAM5 & RAM6 pins 10.
If the self-tests pass, that should be good.
More plausible: check between LSPC2-A2 pin 112 and cart slot CHA A3 (bottom connector, top row of pins, third pin from the left).
If the self-tests pass, that should be good.
More plausible: check between LSPC2-A2 pin 112 and cart slot CHA A3 (bottom connector, top row of pins, third pin from the left).