Guess what my NBA Jam trouble is?

demogo

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Anyone care to hazard a guess as to what my NBA Jam problem might be?

Getting weird intermittent problems.

Tonight when I fired up NBA Jam, the game made a weird buzzing noise and the image on the monitor looked distorted so I powered it off. This was maybe a minute after the game came on and booted okay.

When I powered it back on again the game didn't boot properly (got garbage on screen but I waited a moment and then it booted).

And the marquee light blinked out and back on again a few seconds later. I've seen it do this before and I don't believe it's an issue with the light itself.

I've also seen some weird bootup type behavior with the game in the past. And now that I mention it, Gauntlet Legends (which shares the cab) has acted up a few times right after the game has come up. Game has refused to boot a few times, other times it has booted but the hard drive started making clicking sounds that weren't normal so I rebooted and everything was well.

When the games don't act up, which is 80% of the time, everything seems to be good.

I'm thinking a power supply issue but it's a new power supply? Other than checking voltages to make sure they are right at 5v or slightly higher, does anyone have any other suggestions?
 
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for NBA Jam, 5.10-5.15 at the JAMMA edge might be suffice. I don't want to encourage you going too high, cause the Vegas board will get pissed. lol

outside of that I have no real world experiences equivalent to this to help you with. :/
 
for NBA Jam, 5.10-5.15 at the JAMMA edge might be suffice. I don't want to encourage you going too high, cause the Vegas board will get pissed. lol

outside of that I have no real world experiences equivalent to this to help you with. :/

Thanks.

I'm pretty sure I've checked the voltages on a rom before and it's been right where it needs to be, just slightly over 5 volts.

Because it's happening with the marquee, I'm really thinking it has to be wiring or power supply related with extra suspicion on the power supply. I'm just not sure what the next step is for tracking an intermittent problem like this.

Because it's happening with the GL and NBA Jam boardsets I'm thinking it's not a board related issue.

Incidentally, the shithead technician from Namco had the power supply turned up to near max so the 5v was pumping out over 6v for probably 10+ hours of game play to the Vegas boards when I got it. They don't seem to be the worse for wear from it though.
 
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for NBA Jam, 5.10-5.15 at the JAMMA edge might be suffice. I don't want to encourage you going too high, cause the Vegas board will get pissed. lol

outside of that I have no real world experiences equivalent to this to help you with. :/

NBA Showtime uses the Vegas board, not NBA Jam.
 
Anyone have any ideas how to troubleshoot this?

I can fire the game up and try to read the voltages on the board and jamma connector but whatever the issue is seems to disappear after about 2 minutes.

Can I unplug the jamma cable and just test the voltages w/o anything plugged in to it?
 
NBA Showtime uses the Vegas board, not NBA Jam.

I was referring to the Gauntlet, sir, since he's running both boards in the same cab and it would be impractical to keep adjusting the +5. that was Vegas, right? not Seattle?

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try unplugging the marquee first, see if that helps. never know if some asshole might've replaced it with a fixture that uses a ballast instead of a FS starter and maybe the ballast is quitting on it and interfering with the power supply. I don't know what kind of cab you have, if it's got an iso or not.

you can test the power supply without anything connected, but for a very short amount of time, because a switching power supply requires a load in order to work properly. some people say between 10-15 seconds without load, then get ready to shut it back off.

really the ideal thing to do would be to replace the PSU, I'm not sure it really matters if it was turned as high as it was, surprised your Gauntlet board didn't get cooked. lol but just to rule it out.
 
I agree that it may actually be the marquee light! I've had a few games that when the game first came on and the light was trying to come up, it would cause all kinds of trouble with the board booting up.


Over 6V, I'm really surprised you didn't fry something like said above. Anything over about 5.4 is reallllly way too high. No reason any board should have over about 5.15 at the chips.
 
OK, I'll try unplugging the marquee and see about testing the power supply with nothing plugged into the jamma cable.

The problem is intermittent so this may be a bugger to run down.
 
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