GCC Super Missile Attack Boards

tb lilley

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I've got two Super Missile Attack Boards - the type that you plug into a Missile Command PCB.

One of the boards is for sure a GCC board - it is clearly marked as such.

The other one is a bit different - no GCC markings on it anywhere. The non-GCC board seems to have had some sort of replacement chip fitted in the middle of the board. This replacement chip is 16-pin and sits on a daughterboard with various jumpers ... The chip on the GCC board is 20 pin ....

Anyone care to speculate what this board is? Could be that GCC changed something in the middle of the production run (but seems unlikley). Or could it be a bootleg of the GCC board (which is itself is a bootleg)?

Neither board works - but probably won't take much to get up & running. Pics attached.

First 2 pics are GCC board - component and solder side. Second 2 pics are the other board.
 

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How did I miss this thread??? :p

After reading up a bit, it sounds like the center chip might have been a rudimentary attempt at code encryption? Check out mowerman's notes on ionpool:

http://www.ionpool.net/arcade/sma/sma.html

What intrigues me is how did he determine that the code was encrypted in the first place? Without having a schematic or SMA here it's difficult to get the full picture. Perhaps the second board uses a replacement cipher chip that GCC suddenly couldn't get? It would be interesting to compare the checksums of the two PROMs on both boardsets.

The cipher chip on the first board looks bigger / more pins than the second. The second is a 16-pin'er. Maybe it's just a bipolar PROM where the other is a PLA.

Also, on one board there's a patch (?) socket that is offset. Wonder what that's about?
 
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