Small update
I've been trying to work out why the hold relay wasn't latching on.
After studying the schematics I decided to trace the wires, turns out that the hold wires loops to the coin lockout and one of the wires had fallen off.
I thought it strange that it would be done like that, anyone have a reason why?
Anyway now it is resetting, and I can start a 1,2,3 or 4 player game.
No chimes yet and some of the score reels are not carrying over to the next reel when they hit 9
I also have rebuilt the coin unit, it was really gummed up but it works smoothly now

The hold relay is energised from the moment the machine is turned on. In the home environment, owners bypass the hold relay to eliminate the hum, and the noise it produces. They may have removed the power to the coil and adjusted the leaf switches to be NC (normally closed) - thus bypassing the need for the coil.

Next phase of testing - Test the game in one player only. Adding more players will introduce new issues and add confusion. The player unit on these games is where most of the problems will reside. So you need to test game functionality - or at least having a working 5 ball game - with 1 player only.

If you want to be cheeky - tighten all the switch stacks on the player unit. Make sure the coil and sleeve work correctly. Don't dismantle the player unit YET. It is another stepper unit, but it is a lot more complicated !

All chimes not working ?