Create a GAL for Bally SOUNDS DELUXE audioboard
Replacement of the PAL
Repair of an Bally SOUNDS DELUXE audioboard and replacement of the defective PAL (protected).
Create a substitute GAL by reverse-engeenering.
Presentation
The SOUNDS DELUXE board in installed in the Bally pinballs : Party Animal, Special Force, Heavy Metal Meltdown, Dungeons & Dragons, Escape from the lost world and Blackwater 100.
Built on the basis of a 68000 CPU, it uses a PAL 16L8 for the decoding of the addresses which makes it possible to reduce the number of components.
It often happens that this board is faulty because of the GAL, because over time, this programmable component ends up being erased.
Replace the PAL
We are going to replace the PAL 16L8 by a GAL 16V8, a component compatible with pin to pin and above all still available.
Because the original PAL 16L8 is protected and cannot be replayed, a performance analysis must be performed to determine the logic equations. We use a functional circuit, which we mount on our universal test bench.
One of the functions of this bench is to allow the individual control of the pins and to quickly visualize the state of the outputs.
With a little experience, the GENERIC DIP tool is perfect for this kind of analysis. We can thus quickly establish the behavior of the circuit according to the state of the inputs. All that remains then is to transcribe all this in the form of logical equations.
These will be entered into software such as WINCUPL or similar, and compiled to generate the JEDEC file suitable for PAL.
It only remains to install the new GAL in place of the PAL on the board.
Distribution
This achievement is available in our shop.
