After many hours going over this board with the DMM checking continuity, i have finally found the problem, as i originally thought, it was a broken trace where the previous repairer had changed a chip and put in a socket.
There were 4 re socketed chips all up.
I went through the schematics with both sound boards, and compared the findings with the working board.
Hooray
![yippee #*#](http://www.aussiepinball.com.au/Smileys/classic/yippee.gif)
i have repaired the trace and the board works 100%
![Overjoyed $#$](http://www.aussiepinball.com.au/Smileys/classic/Content_27.gif)
thanks too those who offered help with this problem
![Clapping @@*](http://www.aussiepinball.com.au/Smileys/classic/clapping.gif)
Ian