Contra PCB (possible boot) - 2P controls don't work

MmSadda

Well-known member
Joined
Mar 28, 2009
Messages
1,162
Reaction score
42
Location
Columbus, Ohio
Contra PCB (possible boot) - 2P controls don't work

I got a Contra PCB recently, and aside from some minor possible graphic issues (maybe a loose socketed chip?) and a hiss in the sound (bad cap?), it seemed all right in 1p mode. Upon starting a 2 player game, the 2p start button worked fine, but the 2p controls just don't seem to register at all.

Any idea what might cause this? I tried cleaning the JAMMA edge just in case the side with the 2p controls was dirty, with no luck. I know the controls in my cab work fine, as I've used it for several other games recently with no issues whatsoever.

Does anyone have any idea where my problem may lie?

Thanks

Collin
 
If you have a logic probe check the pins for the player 2 inputs and see if they are at logic level 'high' when no controls are being moved.

If they aren't, look for a bad resistor pack. If they are, follow the pins back to the chips and replace the bad chip.
 
Gotcha, so the board is broken then?

From a conversation being had on neo-geo.com, I'm becoming pretty certain this is a bootleg, which makes me think it's likely not worth repairing...
 
First check and make sure your P2 joystick has a good ground. If so, see above. Input problems are usually pretty simple to fix. Once you verify your wiring you can use a logic probe on each input and watch it go low when you activate the switch. Like CM said, if any inputs are not being pulled high then you probably have a bad/broken pullup resistor(usually done with sip resistor network) or a shorted cap.
Nothing wrong with a bootleg boards. Alot of them you cant tell the difference when your playing it. Anyways, sounds like a simple problem so I would say its worth fixing.
 
Back
Top Bottom