Double Dragon Problem

ThunderBunny

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Picked up a Double Dragon the other day, all in all it's in good shape. I have one little problem that I can't figure out. Player 1 joystick doesn't work, it will let me go up and down but not left or right. As soon as I unhooked all the connections to the controller player 1 started walking to the right. If I put the ground to it he stops. Thinking there was a short somewhere between the joystick and the board I desoldered the player 1 right pin altogether. He still walks to the right by himself. Any ideas?
 
Ok, completely disconnected the stick. I have the 1st player right unhooked from the JAMMA harness. Doing a continuity test between down, up and left, I get about .500. I get nothing when I test the right. Hook the right back up to the pin and now I get a .001 with it connected back to the board. The guy I got it from said he talked to somebody that said the "resistor pack" was bad and that it was fairly common with Taito stuff. He pointed out IC107 on the board. Does that make sense to anyone?
 
Pull out the PCB tray on the bottom of the cab. The resistor pack is located behind the pcb. The JAMMA harness exits the PCB, goes to this pack, then continues to the cab.

If that's your issue, you'll need to meter those resistors. If one is causing problems, then you'll need to fix it.

Do you have another JAMMA game you can test your board in?
 
Looks like my DD was put into a Dynamo can but anyway I dont see a pack. Harness goes right to the board. I dont have another JAMMA to try it in. uploadfromtaptalk1327585113013.jpg
 
Sounds like a board level problem. Figure out which pin on the JAMMA connector controls the right movement, and follow the trace coming off that pin. Something's got to be either bridged or shorted to ground for that input.
 
I have a couple of DD boards I can look at tomorrow if you can identify the issue.
Controller I/O usually have a fairly basic resistor pack that is still readily available.
 
I think I traced it back to an IC. Not at home to say which one it is but it is one of the many SN74F244N's. I pulled(broke) it and hooked the board back up and the walking on his own wasn't happening anymore. Now my question is, where do I find one of those? I ordered one from Mouser that has the same number that was a Texas Instruments though.
 
as long as you get the same type of IC you shoudl be fine.

that is if the circuit is a 74LS244,
any generic 74LS244 should work. The other letters before and after the part number are just specific to the manufacturer and other random properties (like whether it in a plastic casing or a ceramic etc)
 
Yay! Nice work. I have TWO DD boards on my bench that I would like to troubleshoot this winter, and this is giving me some motivation to bust out the logic probe :)
 
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