N64 RGB Help pls

Started by 8ig80y, September 26, 2008, 08:57:01 PM

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8ig80y

Hi i think my vdc-nus is broken  ??? i think the green output is fried  ??? Im measuring a much smaller resistance between (pin 19) green output and ground compared to red output and blue output?  Anything thats supposed to be green is the wrong color, luminance red and blue are working fine. Is there anything i can do to repair it?

I think its likely im going to have to hunt down another n64, goin to be a pain and my n64 mb is a nus-cpu-03 too  :-[

viletim

No doubt, you've blown the output. What happened?

Link83

#2
Are you sure the RGB mod wires are still firmly connected, particularly to the VDC-NUS chip?  I would try resoldering all the connections first, or try another cable before buying another N64.

Out of curiosity did you use the 'internal link two points boost method' as it is known to make the VDC-NUS chip get very hot. If so i guess it could have possibly damaged the VDC-NUS chip, or the 110ohm resistors on the bottom of the board?

8ig80y

#3
Thanks for the advice link and viletim. I've found me another ns10 n64, hopefully when it arrives and i open it up its a version 3 mb.

I was fiddling around with my rgb to component transcoder kit and made a mistake in the connections which fried the green output on the vdc-nus chip. I've undid the mistake and it appears to be working fine with my saturn.

The reason I was fiddling with the transcoder was because the picture would lose stability randomly. Like once in 20 minutes either the picture would go out momentarily or it would bounce a little. This drives me crazy when im aiming for a highscore in an intense shooter.

The problem seems to vary from console to console.  n64 and saturn are really bad with this issue. Whereas the ps2 and the dreamcast seem to be just fine.

I've just recently noticed that when someone was using the blender in the kitchen, these symptons would occur and thered be no picture for a short moment or the picture would be jumpy. This also seems to happen sometimes when somebody turns off the light in the bathroom.

The saturn and even the dreamcast would get unstable when the blender was being used but surprisingly the ps2's picture was steady.

I'm really not sure how to go about fixing this. Is this something that can be fixed by modifyiing the transcoder or its power supply maybe? Or can it be fixed by somehow isolating it from other appliances by using another power point or ups maybe?

Im using the transcoder kit sold by Jaycar from http://www.siliconchip.com.au/cms/A_102648/article.html. To look at the circuit You can click on the small picture of the transcoder and out comes a popup and then you can keep clicking on "next image" until you see the schematics. And also includes the fix at http://www.siliconchip.com.au/cms/A_104857/article.html which uses an lm1881 and a 2n3906 to inject the sync signal in the Y output.



Meh, after typing so much i think i'll just go buy me a better transcoder and give up on this one..... :)




viletim

8ig80y,

You're right in suspecting the transcoder. The design is a silly joke which requires a user-submitted hack just to work at all! The author probably didn't test it on anything but his fox box. It's missing a clamper circuit so it'll only work reliably with DC cupled video. That discounts most game systems.

I noticed that jaycar no longer sell the kit, I wonder why...

Best get a proper one which is advertised to work with video games.