buttons on arcade machine have stopped responding

[trenal]

Hey,

Ive got a 6 slot neo geo cabinet which I had an intermittent problem with but it now appears permanent. In the past when the buttons stopped working (All buttons stop responding on the control panel but the test/service/volume knobs on the door all still work) I would jiggle around with the wiring a little bit to get it to work. Now it seems more permanent and this time around ive also lost response from the test and service buttons along with all the buttons on the control panel but at least the volume control still works. I fear if i jiggle the cabling around some more ill probably lose that as well.


Ive searched around and have been given the tip to check the grounding which sounds like it might be common to all these buttons, any tips for how exactly I go about doing this? Ive looked around at the wiring coming from the buttons (particulalry the black ground wires), through to some molex connectors and then through to the jamma harness but I see no visible signs of loose wires or anything.

Thanks
Alex.

[sosuke]

Get yourself a multimeter with continuity check (make sure it has that ability) and check to see where the breaks are. You put your ground probe on one end of the wire and the other probe on the other end of the wire. If the meter makes a beep (assuming you buy one that beeps, READ THE MANUAL) then you have continuity and that isn't where your break is. Once you test one that doesn't make any noise, that is where your problem is. Replace that wire. Of course you might just have a loose connector somewhere, make sure everything is actually plugged in before you do anything else

I would start by checking that molex connector (and jamma connector), unplug it and plug it back in. If that doesn't do anything. Unplug the molex connector and check your continuity from the buttons to the molex connector to make sure they are all good. And then check from the molex connector to the jamma connector.

[trenal]

thanks for the advice, ill get myself a multimeter and check some of the wiring.

One further question; could one bad wire be responsible for causing all the buttons to stop working or will it more then likely be a combination?

[shardian]

If the ground wire isn't looped, yes it can make all buttons stop working.

[trenal]

If the ground wire isn't looped, yes it can make all buttons stop working.

What do you look for to check if this is the case?

[shardian]

If you ground isn't looped, then you have to start at one end and work your way back until you find the break. However, since ALL of your controls aren't working, it is probably near the molex connector, or even farther back.

[SavannahLion]

I thought there was an illustration somewhere on here but I seems to have lost it. 

So here are my piss poor illustrations.

The first is if you don't have a ground loop.
The second is a break in the middle. The last two buttons are no longer functional.
The third is a break near the PCB. All the buttons no longer work.

The fourth is a ground loop.
The fifth with a break in the middle. Still functioning.
The sixth is a break on one lead back to the PCB.
The seventh is a break on one lead and in the middle. Two buttons dead.
The final indicates a problem with the PCB or connector. All buttons dead.

[trenal]

Im yet to get a multimeter to test for sure, but since all my buttons stopped functioning im thinking with the above info I should check first up the immediate ground connections coming from the jamma harness to the first molex connector then keep going from there.

I have been stretching this area as well when moving the jamma harness to other game boards while the other molex connectors up the chain along with there wiring are well fastened to the walls of the cabinet.

[sosuke]

Unfortunately the only real way to check those connections is with a continuity tester/multimeter. Unless it's a blatantly visible connection problem (a wire is cut in  half or something is physically busted in a very obvious way) you won't know until you test it. The wire could have a break somewhere in the middle under the insulation and everything will look fine to you, but there is a break in the circuit because the wire is busted and you can't see it.

[trenal]

I got a multimeter and was able to detect the dud wire - it was one of the grounds coming straight from the jamma connection to the first molex connector. Cheers for everybodies assistance.