Well guys i have to eat some crow it appears that the crapy sound that i thought was a fault is actually the right sound for this machine.
Having never heard the sound work on the machine before i thought that i should see if there was any video of it on the web and there it was that same repetitive sound that i thought was a fault.
So thanks again to everyone who helped sort this out.
If you guys want to listen to the machine here is the site.

http://houstonpinball.shutterfly.com/pictures#


Cheers
Wally