Run the display test. I see this from time to time, and it's often the 6264 RAM on the DMD controller. Cheap and easy fix! The display test will report the errors.
+1
Even re seat the RAM chip and look for any bent pins which can happen when you swap ICs from board to board.
Cheers guys,
I have run the display test and it reports Ram address errors.
This is unclear as to weather this is the 6264 on the CPU or on the display driver board,
But by being able to carry the fault across machines by swapping the Mpu board leads me to believe its that board.
Alas williams decided it was best to solder the 6264 directly to both boards so not able to swap easily..
Will have to be cut off and socketed with dip28s
Can you substitute a different speed 6264 to the original?
I think the original chip is 150ns and most available now are 70ns..
