Create a GAL for Bally SOUNDS DELUXE audioboard

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Sounds Deluxe

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.

Sounds Deluxe

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.

PAL16L8 GAL16V8 GAL16V8

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.

Sounds Deluxe Sounds Deluxe

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.

Sounds Deluxe

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.

Sounds Deluxe

Distribution

This achievement is available in our shop.

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Last update of this page: June 21th, 2021

French Tech

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