Following HowardR 's help I managed to get the machines playfield powered up and all seemed ok, though it never went to game over correctly. The motor shut off, but the playfield was still live. However, today, as I'd not had time to touch it since, I switched it on again today so that I could fine tune it, etc and fix the game over issue. . But after some time the O relay began to stay locked in and out at times with the motor constantly running. I have tried to find the problem but no joy and it's now continually doing this:

From start, reels zero, credit reel decremenents, motor continues to run and the O relay pulses on and off and the 5 balls do not release. The playfield is live, I.e flippers, pops are ok. Manually releasing the balls and adding 10 points will energise the ball trap relay ok and the motor stays running. If i drain all five balls, it kicks the game over relay in, match light and game over light comes on in backglass and the O relay is always now energised and playfield is still live.
If i start the game again, the cycle stays the same.

To give you an idea of how bad it was when i first started work, take a look at the images, before and after ( ignore the earth cable, its left loose in case I have to pull the motor board out). Lots of stray cables, cut, coils missing ( I bought the machine as a project....)

Any ideas and suggestions welcome!

IMG-20211110-WA0002 (resized).jpegIMG-20211028-WA0008 (resized).jpegIMG-20211028-WA0001 (resized).jpeg

It was pulsing, along with the O relay.
What I've done today was to pull the board out of the machine so that I could look better at the D relay and O relay and the motor switches. I did find one shorted switch on the spin J relay and then checked and re-adjusted my D and O switches and the game now runs, will play 5 balls and go to game over and shut power off to the playfield. So thats good and thank you for your help for pointing me toward the problem.
I have however, noticed now another odd fault in that if the game is tilted, it wont start either using the coin door switch or credit button ( it's set for free play). The game is lit up with the tilt lamp showing as it should. But if I unplug the machine and start it from cold so to speak, it's ok and will play a game fine.

Any thought as to why this is happening please?

I'm scratching my head with this machine. Raising the playfield to check to see if the S relay trips and pressing the credit button, it promptly tripped and the machine fired up. Yet beforehand it would not start from tilt mode.

The only thing I've noticed is that there was tiny particle residue on the contacts from cleaning all the relays in the bank with a brand new flex-file thing that I bought along with all the other new spares for it. I've now carefully cleaned it all off with compressed air and vacuumed it and it's now fine after 10 or more plays. Must have had a contact bridged or something? I'm marking this resolved and thank you, Howard, for your help.