A little help with S-Video?

Shield

Member
Hey Guys,

I looked at the sprocket64 by Mario http://forums.modretro.com/viewtopic.php?f=33&t=442&start=10, he found a way to use the s-video driver chip pins to get his 7" LCD to use the S-video input, and I want to make s-video work on my n64 portable.

I got a 7" Car LCD with 800x480 resolution and even VGA on it through ebay, below is the datasheet, from what I can see it looks like it says s-video is on pins 16, 17, 18 and 19, (see Picture) any advice on how to try and hook up the chroma, luma and ground pins of the n64 to the LCD chip pins without frying anything, like grounding something, I don't want to hook up a wire somewhere and fry it.

PDF File of Datasheet, Page 4 of the PDF shows the pin-out and page 5 shows Analog interface pins.
http://www.datasheet4u.com/datasheet/M/S/T/MST703_Master.pdf.html

bcrJ8xD.jpg

NZYnKaS.jpg

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I marked and highlighted the pins and traces.
UPG2pxd.jpg



Basically I want the best quality image the n64 can put out, I have seen people do a RGB mod but it looks like you need a 50$ board from the UK or a n64 with a serial number starting with NS1 to make that happen, maybe in the future.
 
I want to make sure I have this understood.

I have made progress in my attempt to use S-Video on my 7" LCD,
the thing is, I'm not sure about this, I thought I would have to connect the Chroma (C) and Luma (Y) to the driver board for it to work, but I am surprised to find that it really only needs Chroma (C), when I add Luma (Y) it turns to a black and white image, Is that normal?

The driver chip says it works with both Composite and S-Video and has 2 sets of pins for both, only the 1st set seems to be set up to work.

I have not taken my n64 apart yet, but I purchased one of those S-Video ONLY cables and put some clips on the pins of the s-video connector and attached them to probes, both Chroma and Luma Grounds to the ground on the LCD, then rigged up probes for Chroma and Luma and start probing the S-video lines.

It looks like an increase in sharpness.


Chroma only
gHkYTfT.jpg


Composite
6zorGAo.jpg


Chroma and Luma
iYMCqDL.jpg
 
You need to open your N64 and check the continuity between the SVideo cable and the N64 AV header pins. It took me a long time to find an SVideo cable that was actually SVideo for my personal use. I may have ended up making my own. If my memory serves me well it seemed like all the cables I bought used the Composite Video line for half the video signal (either Chroma or Luma). So you may not be actually getting an SVideo signal at all. Also I know that if you plug Composite Video into the Green (Y/luma/sync) line on a Component Video Input you will get a black and white image.

Also, don't waste your time with RGB. You'll probably end up adding more PCB's to your portable that increase size, weight, and power consumption. I've spent alot of time messing with RGB and I can tell you it doesn't look much better than SVideo. At least with the method I was using. I was using a GBS8200 CGA/EGA/YUV TO VGA video converter (which is very useful because there's not much out there that handles 31K signals) and a video amplifier on the RGB lines coming from the N64 (there's a guide out there by a dude by the name of mmmonkey). And I could never make it look better than SVideo. I use a V2V PRO to go from SVideo to VGA and its the best video quality I've managed to get out of an N64 to a modern HDTV/Monitor.
 
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