RGB modded N64 - LCD Television issue...

[paulpsomiadis]

Okay, this has been bugging me for a while now, so I FINALLY decided to do something about it.

I have a nicely modded USA N64 with the following done to it...

1) RGB lines output directly from the VDC to the AV out.
[Kynar wire routed through the mainboard VIAs to avoid having to cut/mod any case parts]

2) 1.5X speed overclock (and a nice custom CPU heatsink too)

3) Swapped the USA lockout chip for a UK lockout chip so I could play all of my PAL N64 carts at 60Hz

4) Custom SNES RGB cable [see below for the additions made]

Got the RGB & OC info from GameSX:

http://www.gamesx.com/rgbadd/rgbn64.htm
http://www.gamesx.com/misctech/n64oc.htm

Built an American SNES RGB cable as according to THIS site:

http://members.optusnet.com.au/eviltim/ ... escart.htm

The only two differences are that:

1) Pin 3 (Comp Synch) and Pin 9 are linked
[U.K. SCART sockets expect these signals on the SAME pin]

2) There is a signal booster built-in for each RGB line so the N64 picture isn't SUPER dark.

(note that the signal booster is NOT the source of my issues, as I initially tried the lead without the booster)

Anyhow - FINALLY, onto the "problem"...

Everything was GREAT with my old CRT Television...

Then I went LCD and my N64 decided to play foul!

(bearing in mind that my PSX, Saturn and G.C. ALL work fine through the SCART socket of my LCD Television...just not the N64)

Basically I tested ALL my N64 carts and got the following results on my LCD telly.

TUROK 2 (using exp. pak) - FLAWLESS!
Resi 2 (using exp. pak) - works 1/2 the time
Star Wars Ep. 1 Racer (using exp. pak) - works 1/2 the time

ALL other carts - e.g. Zelda, Waverace, Goldeneye, etc...

These "low res" GFX carts are the ones that don't want to behave.

I get a picture all right - but the top half of the video is horizontally unstable. It shifts from left to right flickering VERY fast.

I'm SURE it's something to do with composite synch, but I can't seem to get an idea of exactly WHAT is causing the issue.

Some questions I'd like to ask are...

What are the low / high res modes of the Saturn / PSX and N64?

If my LCD telly supports all the modes of the PSX and Saturn (which it does with EASE) - should this mean it will also support an RGB modded N64?

I thought about building a homebrew synch stripper and making a VGA cable MOD with it...

http://www.avforums.com/forums/showthread.php?t=199751

Unfortunately my T.V. only supports 30kHz on it's VGA input - so a PRO scan-doubler would be my only option...BUGGER!

Anyhow...enough for now...

Your thoughts people?

[marshallh]

Sounds like the C-sync line might be too weak for the TV's tastes. You might have to try amplifying it.

[paulpsomiadis]

Hmm...so instead of a three line signal amp...

I just add another amp for the c-synch signal as well.

...problem is that the amp "barely" fits inside the SCART plug hood as it is!

Hmm, I guess I'll have to internalize the AMP in the N64.

Although in hindsight - this is probably safer anyhow!

For others who need a signal amp, there's a simple GOOD amp here:

http://www.gamesx.com/grafx/pce_rgb.jpg