THANK YOU !
All sorted.
Firstly, my -5v was all to cock, ripped out the power supply and put in a new one. That cured the horrible hum from the speaker, but not the graphics.
On the two board stack were smaller chips that could be reseated. Originally I just did the larger eproms and overlooked these,mistake!.
Anyway, these three smaller chips were reseated, and one of them had two bent pins. I should really name them but I've just put the game back against the wall.
Straightened the pins out oh so very gently, my god they are fragile..., reseated these ones very very carefully.
Job's a good'un
Here's the result.
http://youtu.be/mAFRLqebZUAThanks a lot guys, might seem like basic stuff to you both, but for me this was new territory.
It was fun, especially since it worked.
Thank you.