Quomonster
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- Joined
- Jan 19, 2025
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Clearly this is a "nice to have" working as opposed to game play critical. I did some testing and found that the LED in the switch is good and that it is not receiving the flash signal from the game board. I managed to find the 2 Player start signal coming off the board using the logic probe, but was unable to find the 1 Player start signal coming off the board. This brings up a couple of questions.
First, I see that Start LED 1 is referenced as "P" on the edge connector and should feed a W/R wire. Start LED 2 is referenced as "H" and should feed a W/B wire. I am having difficulty determining how the referenced numbers and letters correspond to the edge connector / socket plug connector positions. Is there a standard for how these are laid out? Do I start counting down one side and then in reverse down the other side? I am assuming that H would be 8 spaces away from P on the same side of the edge connector. It is difficult to see the colors of some of the wires in the harness, so I was looking for a "map" of some sort. On the schematic the wires are shown in a "random" order that is more suitable to the layout of the drawing. Any suggestions here?
The other thing is I can't find anything in the schematic that indicates which chips on the board are related to the Start LED outputs. I do see in the memory map that a D1 bit somewhere in the high 48xx region is responsible for 1 Player Start LED Output. So there is the possibility of bad RAM causing the problem, but this seems unlikely since the game is otherwise almost completely working. (it also has the missing Earth problem which I am pursuing here, btw):
Can anyone tell me how to determine which chip / pin should be feeding the 1 Player Start Led Output, so I can attempt to test the chip and possibly other related components on the board?
As always, any suggestions are greatly appreciated - please and thank you!
JC
First, I see that Start LED 1 is referenced as "P" on the edge connector and should feed a W/R wire. Start LED 2 is referenced as "H" and should feed a W/B wire. I am having difficulty determining how the referenced numbers and letters correspond to the edge connector / socket plug connector positions. Is there a standard for how these are laid out? Do I start counting down one side and then in reverse down the other side? I am assuming that H would be 8 spaces away from P on the same side of the edge connector. It is difficult to see the colors of some of the wires in the harness, so I was looking for a "map" of some sort. On the schematic the wires are shown in a "random" order that is more suitable to the layout of the drawing. Any suggestions here?
The other thing is I can't find anything in the schematic that indicates which chips on the board are related to the Start LED outputs. I do see in the memory map that a D1 bit somewhere in the high 48xx region is responsible for 1 Player Start LED Output. So there is the possibility of bad RAM causing the problem, but this seems unlikely since the game is otherwise almost completely working. (it also has the missing Earth problem which I am pursuing here, btw):
Earth missing from Missile Command playfield
A friend and I have been working to restore functionality to his Missile Command cabaret. We have worked through several issues already and the final issue seems to be: The Earth (ground) is missing from the Missile Command playfield. On the first level the ground should appear as yellow, so...
forums.arcade-museum.com
Can anyone tell me how to determine which chip / pin should be feeding the 1 Player Start Led Output, so I can attempt to test the chip and possibly other related components on the board?
As always, any suggestions are greatly appreciated - please and thank you!
JC

