Thanks everyone!!

I couldnt get the schematic to download off marvins site. I didnt think they were 1n4004 as these are used throughout  the PF, but the coin door switches are glass type and so i wondered why the difference.
 You know after extensive searching on the web, i couldnt find these labelled as what type they were.

All i got was " if door switch diodes fail then replace" and other such generic statements.
VERY irritating non specific information!

Ive follopwed marvins guide to the earthing upgrades on this machine and also re earthed the whole cabinet etc - no  more shocks!

However, this has not stopped the faults..

Previously the zener had gone on the power board for the 8.2V, ive replaced this and done the upgrades as mentioned. Game does not boot ( it did sometimes previously). Testing voltages on power board reveals them all to be slightly too high.

5V - cant get below 5.5v
 8v - is 11.5v ( zener is good)
42v (?) - is a whopping 60v
60v is  something like 75v

Any clues?? all help appreciated as this will save me some time..

Thanks  gavin