Williams Sys 4 question

brypten

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Eprom question here. I have read that you can put a 2716 at IC location IC14 with no jumper changes. I have a sys 4 board that was supposedly working, yet it has a 2732 at IC14. The board is really clean, no cuts or jumpers.

Whats weird is that on the Eprom it says "Tri-Zone U4 2732" and it is a AMD 2732DC.

Any insight? I can't believe it was working but maybe it's a 2716 image?
 
maybe it's a 2716 image?

Probably a doubled 2716 image. That would work.

If you look at the pinout of both EPROMs you'll notice that there is only one pin that's different. Pin 21. It's A11 on a 2732 and VPP on a 2716. Assuming pin 21 is pulled either high or low in the game a 2732 will run fine in place of a 2716. You just have to double up the ROM.

This command will double the ROM in DOS:

copy /b original.rom+original.rom doubled.rom

Where original.rom is the name of the original ROM file and doubled.rom is the name of the new file to be created.

In this case it might look more like this:

copy /b tri_zone.716+tri_zone.716 tri_zone.732

If you're going to do any serious troubleshooting of the MPU I suggest Leon's test ROM:

http://www.pinrepair.com/sys37/index2.htm#leon
 
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Probably a doubled 2716 image. That would work.

If you look at the pinout of both EPROMs you'll notice that there is only one pin that's different. Pin 21. It's A11 on a 2732 and VPP on a 2716. Assuming pin 21 is pulled either high or low in the game a 2732 will run fine in place of a 2716. You just have to double up the ROM.

This command will double the ROM in DOS:

copy /b original.rom+original.rom doubled.rom

Where original.rom is the name of the original ROM file and doubled.rom is the name of the new file to be created.

In this case it might look more like this:

copy /b tri_zone.716+tri_zone.716 tri_zone.732

If you're going to do any serious troubleshooting of the MPU I suggest Leon's test ROM:

http://www.pinrepair.com/sys37/index2.htm#leon


I wasn't sure if Leon's test ROM would work since it's IC14 on this board. Never worked on a System 4 board before, all my others ones are sys 6 and 7.
 
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