NNC No signal

J69

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Bit of an odd issue on my NNC

I’ve just bought an NBA JAM board. It works fine on my Jamma’d DinoKing but when I try it on my Jamma’d NNC I get no video signal. Yet all my other games work on my NNC?

Any suggestions please?
 

J69

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Yep. CPS1 games, MVS games no issue. NBA jam just won’t show a signal no matter how many times I take it out and plug it in?
 

FrancoB

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What monitor do you have in your NNC. Tosh PF?

I had a Sanwa PFX which was a bit picky with sync signals, Taito F3 games and some others (Outfoxies IIRC) would display fine on my other cabs but not on my PFX.

If you have got a Tri-sync monitor then the [Tri-Sync Helper] might....help.
 

J69

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Would a low +5v do it?

I’m using a Jamma extender and the psu is a crap non adjustable one. Seems to be pulling about 4.5v at the Jamma edge
 

J69

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Fixed my own issue. Removed the Jamma extender and it now measures 4.8v and works fine.

Next question, is it possible to get a Jamma extender that doesn’t drop voltage? The one I’m using is a cheap one off eBay
 

FrancoB

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I bet there are only one or two 5v / GND lines on the extension. If there is just add some additional wires.

I used to wire every available 5v and GND connections with 24/0.2 wire.

i-TchXXn9-L.jpg
 
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Fantazia2

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If its one of those Chinese extensions off eBay you will probably find the thicker looking power cables only have thin copper wires inside and have thicker insulation to make them look heavier duty than they are.
 

TheDaddy

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Yeh usual jap crap, Well documented. Same as above i either make my own or replace the cable of the Jap one with the correct gauge & quantity. This is very very common and there have been so many posts that turn out to be that.

some (Not all) Jap stuff is like B&M stuff, false economy - Looks great so you buy it , 12 months later its broke and you have to buy another. We all fall into the " Looks good and great price !!" louring bracket.

Purchased some door latches and within 16 months it broke and it cost me a door as I could not open it so had to smash it in. I replaced 3 at the same time so replaced them all with more expensive ones now, Currently replacing the handles i purchased from them that are falling bits as well. Monkey metal - You can file this metal with your fingers !

Still low at 4.8v though.

Dave.

TheDaddy2020-08-26 20:19:00
 

J69

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FrancoB said:
I bet there are only one or two 5v / GND lines on the extension. If there is just add some additional wires.

I used to wire every available 5v and GND connections with 24/0.2 wire.

i-TchXXn9-L.jpg

I’ll need it up this weekend and see if it makes a difference thanks
 

Retroman839

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not sure if this helps but
i seem to remember somone having difficulty with mortal combat.. recently
and i think it has custom mode line in calamitys crt driver video mode line

because it has a specific to midway 15khz vertical.. 53.2khz horizontal

obviously its the 54khz thats a bit off but yeh midway stuff of nba/mortal kombat era had

a scan frequancy a little bit diffrent... i think..

400x254@53.2hz refresh mortal combat .. i think nba is same?

maybe its a bit to far out there for some monitors
 

J69

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Quick update.

I added extra wires to GND & +5V with the worst soldering job known to man. The Jamma extension isn’t dropping voltage anymore and the game is working fine :D
 
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