Hi,
With the Ind. ECS installed in my A500 I get some random mouse movement when the mouse is unplugged.
When the mouse is plugged in I can only move the mouse Up and Left.
I had already replaced the U15 multiplexer before I realized it was happening only when the Ind. ECS was installed.
I have tried installing a 1.2k resistor between Denise pins 9 &19 as I read on another thread.
This eliminates the random movement but I still cannot move Down or Right.
The voltages at the U15 multiplexer suggest that the Down & Right signals from the mouse do not go from 5V to 0V - the only reduce to 2.5V.
I saw a suggestion to replace the 74LS157 multiplexer with a HC or HCT type.
Could that change help with my direction issue, or is it really only for the random movement that is already eliminated by the pull up resistor?
Thanks!