I also done the ground mods for system 80s boards, i found some of clays documents a little confusing, do you have to run a
ground wire from the power supply metal plate to the ground bus in the bottom of the cabinet, and also do you have to run a ground wire
from the power supply metal plate to the key lock in the machine head.

cheers Ian

some pics.

hey guys do i need to run a ground wire from the power supply bracket/board in the head to the ground bus in the cabinet.

Ian