I want to buy a midi kit and instasll a phone jack. Could you please tell me exactly which spot on the 2600 and 2600A boards are the ground?
This is a common question. (When installing an audio output on the Atari console, the sleeve of the connector should be connected to console ground.)
Ground traces are found all over the Atari circuit board. Pin #8 of each joystick port is also connected to ground. So, if you power off the console, you should be able to identify the ground traces with a continuity tester.
Hope this helps.