Thanks Dann36 for taking an interest in my dilemma. I have attached a couple of shots of the homemade cabling. Btw I just buzzed for continuity from the chassis pins to the amplifier connections and all good. Also buzzed the frame to ground on the chassis connector and to a earth braid and all good. Tested 5vdc and get about 4.9vdc. Finally the 5vdc wire seems ok as I did remove it from the amplifier and got no graphics at all.

Hope this can help with a possible solution. The crt does have a sync jumper but I can't see its location easily or its setting. Thanks again