Re: Issue with picture using Scart to Component Converter w/
Posted: Mon Feb 04, 2013 6:34 pm
Yeah, it gets a little confusing with the Nintendo SCART cables. If the info on GameSX is correct, then RGB SCART cables intended for NTSC SNES will have 220uF caps in series on R, G and B while RGB SCART cables intended for PAL SNES will have 75ohm resistors to ground on R, G, B and composite. I have no idea why, but pin 7 on the multi out is sync on NTSC consoles and 12v on PAL consoles. PAL apparently uses composite video for sync. My transcoder didn't like this though, so I had to tap sync from the video encoder.
Interestingly though, I was playing around a little with my RGB outputs, and created a situation where I got "distortion" at the top of the screen. Only mine wasn't wavy gravy like seen in the above pics, I got a bright horizontal bar at the top of the screen. What I was doing was trying to figure out if I should use a cap or a resistor. If I understand correctly, the caps are there to kill off voltage on the lines while the resistors are used to dim the lines (they'd be too bright otherwise). My RGB lines have 75ohm resistors to ground, are about half a volt, and appear to look correct on my TV. But since I needed sync, which the PAL SNES does not provide at the mulit out, my sync line has about 1.5v on it. That's why I played around with the 220uF cap. Adding the cap on sync, without the resistor, brought the voltage down but gave me that bright horizontal bar at the top of the screen. Adding the 75ohm resistor to ground, while still leaving the cap, dimmed the bar but it was still there and very apparent.
I didn't read the entire thread, but that's my recent experience with SNES RGB and transcoding to YPbPr.
Yes, that sounds very likely. I've been lucky with my HDTVs, but from what I've heard, the problem can vary between TVs. Some will just give you the "no input" message. Others, you'll see the picture but it'll be bouncing all around like crazy. I guess everything in between is possible, including what we see here in the OP.
Interestingly though, I was playing around a little with my RGB outputs, and created a situation where I got "distortion" at the top of the screen. Only mine wasn't wavy gravy like seen in the above pics, I got a bright horizontal bar at the top of the screen. What I was doing was trying to figure out if I should use a cap or a resistor. If I understand correctly, the caps are there to kill off voltage on the lines while the resistors are used to dim the lines (they'd be too bright otherwise). My RGB lines have 75ohm resistors to ground, are about half a volt, and appear to look correct on my TV. But since I needed sync, which the PAL SNES does not provide at the mulit out, my sync line has about 1.5v on it. That's why I played around with the 220uF cap. Adding the cap on sync, without the resistor, brought the voltage down but gave me that bright horizontal bar at the top of the screen. Adding the 75ohm resistor to ground, while still leaving the cap, dimmed the bar but it was still there and very apparent.
I didn't read the entire thread, but that's my recent experience with SNES RGB and transcoding to YPbPr.
theclaw wrote:Some TVs are incompatible with 240p from component input. If all else fails, resolution could be the problem.
Yes, that sounds very likely. I've been lucky with my HDTVs, but from what I've heard, the problem can vary between TVs. Some will just give you the "no input" message. Others, you'll see the picture but it'll be bouncing all around like crazy. I guess everything in between is possible, including what we see here in the OP.