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Old 10-18-2007, 05:25 PM
Geoff Harrison Geoff Harrison is offline
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Join Date: Feb 2007
Posts: 104
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Good find.

It's certainly safe to leave the chip out since it's connected to nothing other than Vcc & gnd. I took mine out.

Looking at that close-up on Erik's site, it looks like the trace from 116.8 to 107.13 (the X4 signal) has been cut and redirected to pin 1 on IC99. That's one of the inputs of a nand gate, the other input is connected to a wire that wraps around to the top of the board that has been cut. The output of the nand seems to be routed to both inputs of another nand to invert the signal again and routed back to 107.13.

When X4 is true and location 377 (input) is being read, the K register will start shifting data in. I wonder if the wire that was cut allowed another input channel that bypassed the buttons.
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