Try this...turn machine off- disconnect connector A3-J4 (on driver board-down/left corner )

Turn power - on (left bank should not be activated)

power -off

Put connector A3-J4 at the "place", but disconnect A3-J1 (between driver board and MPU )

power - on

A) If left bank IS activated you have problem with Q62 (on driver board, one of three "big/metal"
transistors -right one, or (and ?) with Q61 which "drives" Q61

B) If left bank is NOT activated you have problem on MPU board

Greetings from Croatia