Galaga restarts

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Have a Galaga with midway CPU. With Dip Switches set to free play, it will auto restart a 2 player game instead of going into attract mode. I have checked Switch circuits and believe it is CPU. Kinda a noob with Arcades but have been messing with pins for years. Short of swapping my CPU into another machine to test any advise? Thanks
 
Disconnect the edge connector but leave the two molexes connected. This will allow power and video, but remove sound and controls. You'll see it boot up on the screen. If it still starts a 2-player game, then you are correct that it is an issue with the pcb. If it doesn't, then the issue is in the connectors, wiring, or switches...
 
Disconnect the edge connector but leave the two molexes connected. This will allow power and video, but remove sound and controls. You'll see it boot up on the screen. If it still starts a 2-player game, then you are correct that it is an issue with the pcb. If it doesn't, then the issue is in the connectors, wiring, or switches...

Ooh that's good stuff I will try that tonight. So that 44 socket edge connector can be off and CPU will boot up? Again I'm noob sorry if that's super basic.
 
Ooh that's good stuff I will try that tonight. So that 44 socket edge connector can be off and CPU will boot up? Again I'm noob sorry if that's super basic.

Yes. I know that might seem strange, but Galaga is a little different than most boards in that the power and video signals are connected via two extra molex connectors, rather than only through the edge connector. So you can disconnect the edge connector and the game will still function, minus sound and controls as modessitt indicated.
 
Have a Galaga with midway CPU. With Dip Switches set to free play, it will auto restart a 2 player game instead of going into attract mode.

I don't think Galaga will go into attract mode with freeplay enabled. I think it should go to the "press start" screen...
It shouldn't actually START the game, IIRC, but it should sit on the screen that shows when you get an extra ship etc.
Try it in MAME to verify expected behavior.
 
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I don't think Galaga will go into attract mode with freeplay enabled. I think it should go to the "press start" screen...
It shouldn't actually START the game, IIRC, but it should sit on the screen that shows when you get an extra ship etc.
Try it in MAME to verify expected behavior.

That is correct, unless there is some "high score save/free play with attract mode kit" installed...
 
Update.....took edge connector off as suggested. Turned game on and yes after a minute or so it auto starts 2 player game. After game over it goes thru same thing ....after a minute or so auto restart 2 player. There is not a high score save card installed. Any suggestions on what to check or shot gun? I have done boardboard level repairs toto my pins inluding chip/socket. Thanks
 
Attached is the schematic for the inputs on Galaga.

"2nd PLAY START" in pin 10 on the edge connector.
If it's starting with the edge connector removed, then it's not a wiring or CP switch issue.
See the resistor networks (RM6 and RM7) that "pull up" the voltage to +5V? Check them, especially the one connected to the 2nd player start line, of course. If it's not "pulled up" it's said to be "floating" and it can float low, which is "active", and it'll think the button was pressed.

Similarly, I suppose the capacitor between that line and GND (C6) could be shorting, and pulling it low, but that seems less likely.

We hope that the problem is NOT the 51xx custom @ 4H...
 

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Could also be dirty pins on that custom IC... or a bad socket connection.

RJ
 
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