Joust: Game Won't Start

Fatsquatch

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My Joust was working perfectly the last time I fired it up, but today, it's being a lil biatch.

She powers up fine and coins up just fine, but pressing the 1p or 2p start buttons does NOTHING. I've cleaned the wiring connector to the control panel, checked the switch connections on the control panel, and did a reset of the boards, but still nothing.

Any ideas as to what the likely culprit may be?
 
My Joust was working perfectly the last time I fired it up, but today, it's being a lil biatch.

She powers up fine and coins up just fine, but pressing the 1p or 2p start buttons does NOTHING. I've cleaned the wiring connector to the control panel, checked the switch connections on the control panel, and did a reset of the boards, but still nothing.

Any ideas as to what the likely culprit may be?

Press the test button, in the coin door, and step through the test screens to the input test screen. See if any of the other inputs are working.

Also unplug the I/O board from the main CPU board and plug it back in just to make sure the connection is good. Also unplug the 10 pin molex connectors on the I/O and plug back in, just in case.

Check the ground connection on the harness, use a meter and check there that the ground connection on the buttons, the side that's grounded should be tied to a ground on the board.

If you've got a logic probe, stick it onto the molex connector of the I/O board for the start pins and press the 1P + 2P start buttons you should see them pulse when you press the buttons down.

Best case, problem with the wiring harness, probably ground to the buttons problem. Worst case the 6821 I/O controller on the I/O board has passed-away.

- James
 
UPDATE:

I went through the test screens, and discovered that NO inputs were working. I then pulled and cleaned (with contact cleaner) every connector on the boards. When I fired the game back up, it worked perfectly, and I spent about 15 minutes or so playing.

I stepped away for about half an hour, and when I came back, it was back to its old problems -- with none of the inputs on the control panel working.
 
It sounds like 1 or more of the following:

1) connectors that need to be reflowed at the boards.
2) ribbon cable issues
3) I/O card issues
4) Ground strapping issues at the switches

When you did the switch test did any of the buttons work? If not, then look for a ground issue to the control panel. I would start at the molex connector that mates the control panel cable with the cable to the I/O board.

While doing the switch test (a second person helps here) try flexing the ribbon cable to the I/O board. This is a common I/O issue.

ken
 
If you have a set of jumper cables (the little ones not the car type), jumper between the ground line and the metal braid. That hshould let you know real wuic if you have a bad connection to gound in the control panel.

ken
 
Where can I get some new (I/O & ROM board) ribbon cables?

Supposedly Bob Roberts has some. I have not found any from the usual electronics suppliers because the PCB connectors are staggered in an odd pattern.

Usually it's not the connectors, it's the connections to the wires that needs pushing back down. Normally that is at the end that connects to the MPU board because that is where most of the flexing occurs. If you have a vise you can carefully squeeze the cable connector which will often fix the issues for a long while, especially if you use a small flat bladed screwdriver to pry the cables loose at the sides (where the $0.29 cams should be).

Most people just pull the connectors loose by grabbing the cable and tugging. If you look closely at the connector, you will see why this is a bad idea. The locking clamp on the top of the connector will eventually give way slightly allowing the cable to pull away from the IDC blades. By recompressing the connector, you can re-establish the connection without replacing the cable or the connector.

ken
 
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