NBA Jam not displaying on supergun

I made a supergun a month or so ago and have been buying boards for it and haven't had any sort of problem with it. my friend just bought nba jam for his cabinet and it displays no problem. when i went to hook it up to my supergun, i wasnt getting any sort of signal.

I've searched to see if anyone had this sort of problem and found that it needs a -5v. I have a JAMMA extender that i bought that has a -5v. The sound board on his PCB doesnt work properly, but it still displays a picture. Anyone know what the problem could be?

Here's what I'm using:

-vogatek MKII encoder (has S-Video and composite outputs)
-ATX power supply
-JAMMA extender with a -5v line

Im outputting this on an HDTV... could that be the problem? I'm also not too sure if the encoder is able to handle a -5v.

Any help would be greatly appreciated

Since it's a midway board and I hear they have funky refresh rates, maybe the TV just doesn't like the signal.

It's a pretty common problem with midway games, especially Mortal Kombat.

buaku said:

Since it's a midway board and I hear they have funky refresh rates, maybe the TV just doesn't like the signal.

It's a pretty common problem with midway games, especially Mortal Kombat.

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provided that is the problem, is there a workaround for it, or is it a lost cause?

If that is the problem there's not much you can do, except try another TV.
Some say service menu adjustments may work, but not always, plus you run the risk of royally screwing up the TV.

What brand of TV is it? Sony's appear to have the most issues from what I've read on this board.

I would think an upscaler like the XRGB should work. I would try to confirm this first because they are expensive. My HD TV doesn't work with most of my games through the supergun. I haven't tried the upscaler approach because I use a projection TV for running my boards.

-5v should only affect sound for most boards from what I have read about it. I'm pretty sure the Vogatek has no problem with -5v.

Is the power supply providing enough amperage? Check the volage at the edge connector. I had a PC power supply that would dip down to 4.6 volts when I hooked large PCBs to it :cough: Ninja Spirit :cough:

Even though you are probably gonna have a way off center picture, you should still have a picture.

Make sure the +5v line is reading good, just like what was said check it from the edge with the board plugged in. You should see a drop in voltage. When adjusting it make sure you don't go passed 5.25v. I usually set my SGs to 5.15v.

If it's a refresh rate problem, you would at least get a picture, not just a blank screen. I used to have NBA Jam hooked up to a home made supergun and didn't use -5v. It was, however, very picky about the voltage so double check that as mentioned above.

turns out that the power supply i bought for my supergun wasnt even putting out -5v. so it doesnt seem to be the encoder at all, but hopefully the power supply itself.

apparently i need to fina an "ATX 1.0" power supply

I don't think NBA Jam uses a -5v
http://www.crazykong.com/pins/NBAjam.pin.txt

It does for the sound. But for some reason it won't boot properly with out it.

what brand tv?
I have 3 sony tv's that no midway boards work on,
but found a crappy rca tv, hooked it up, and no problems

FOMOCO&CO said:

what brand tv?
I have 3 sony tv's that no midway boards work on,
but found a crappy rca tv, hooked it up, and no problems

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How's the picture on it, perfectly centered? What's the model number of the TV?

FOMOCO&CO said:

what brand tv?
I have 3 sony tv's that no midway boards work on,
but found a crappy rca tv, hooked it up, and no problems

Click to expand...

You got absolutely no picture on the Sony TVs? It's very common to have a rolling picture but I've never heard of Sony TVs not giving any picture.