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Naomi VGA cable

muell67

muell67

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So I'm having an unusual issue with my SVGA arcade monitor and my Naomi. The naomi is working fine it has been tested with several monitors and my monitor is working fine and has been tested with several vga and svga sources. The problem is when I plug the naomi to the monitor everything works but the vga cable starts to heat up. I have been told that the original naomi vga cables were missing a few pins and that having all the pins was causing my problem. Could someone with an official sega naomi vga cable please tell me if there cable does not have all 15 of the standard vga pins and which pins are missing. This seems crazy but worth a try.
 
Yes, it does not have all of the pins. It's weird. The original VGA cable for Naomi does not have them all. I bought a jamma harness on eBay from an arcade representative in s.carolina and it came with a long VGA cable (white exterior). The auction info stated it came from a Naomi setup. After looking at the cables one night. I too noticed that the VGA cable didn't have all of the pins when compared to the standard VGA cable used for PC monitors.

I will say, that I currently use a VGA cable with all of the pins on my setup. It goes from the Naomi 1 to a Capcom io board and bundled together and I have had not noticed any type of heat or warmth from the cable.

Doesn't that usually mean that your wires can't handle the voltage or amps coming through? I forget how that goes. High voltage and thin wires is when you see things heat up. Or is it high amps and thin wires?

Sorry for the long story. I'm bored at work.
 
Yeah I use a regular VGA cable without issue but KO might be onto something. Maybe you should get a high quality VGA cable and try again.
 
Ive used a regular vga with the naomi on my vewlix and its fine. I have also used a regular vga cable with the monitor and a pc. Its something about the combination of the two. Also I did try a higher quality larger gauge wire vga cable and I got the same result. Not as hot but still not normal. I would have never thought it could be the extra pins but I posted the problem on klov first and got a response saying "That is a common problem, I have had it happen before, the original naomi cables are missing some pins, I find removing that pin from the naomi end fixed the issue." I just need to know which pins to remove. The poster on klov hasnt responded back. I figured someone on here has to have a original cable they can check for me.
 
If wires are getting hot it means that too much current is being drawn across them for their size; in essence the wire is being used as a resistor...

A lot of cheap cables have 28awg wires, I try to shoot for 22 awg or larger... 24 awg at the thinnest. (same goes for USB cables, particularly if they're being used for power).


As for which pins to remove. you should only need, Red, Green, Blue, H-Sync, V-Sync and ground. VGA includes some 5V pins and other pins to specify modes and other data that you could theoretically remove without issue.

I have a few original NAOMI VGA cables I can check. I never noticed any of them missing pins, but I also never really looked that closely.

EDIT:
here's a complete VGA pinout
VGA-Pinout.jpg


looking at this pins 4, 9, 11, 12, and 15 could safely be removed.

chances are pin 9 is the one giving you grief. it looks like some older cables had this pin removed, and newer cables run +5V on this pin.
 
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That's not the official cable. the official cable has metallic housings on the plug ends. and the cable itself is light gray. They look like this:
maxresdefault.jpg


I just snapped a quick pick of mine... it's missing pin 9


naomi_vga_cable.jpg


sorry for the potato quality, my battery was so low it wouldn't let me use the flash :-/
 

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twistedsymphony said:
That's not the official cable. the official cable has metallic housings on the plug ends. and the cable itself is light gray. They look like this:
[pic]
Click to expand...
Naomi cabs from Europe have a black VGA cable similar to the one in darkstrider2's pic. I've only ever seen light gray cables on cabs imported from Japan.

(I don't have any US cabs.)
 
Interesting. I didn't realize Europe got different versioned cabs.

My Net city is from Japan, and at least one of the cable sets I have came from a USA Capcom Powerstone kit, which included the same VGA and JVS cables as my Net City.
 
I got a chance to try it with pin 9 removed. I only left it on for about 5 minutes but there was no heat. So it looks like removing pin 9 fixed the problem. I plan to leave it on a little longer before throwing it in a cab but I'm pretty certain that it fixed the issue. Thanks to all.
 
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Did a quick test as I have this stuff on my desk, the Naomi 1 outputs 5V on pin 9, and depending on cable or monitor, this could perhaps introduce a short or high current draw somewhere.
 
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