TV out (svideo) question

[ChrisBardon]

So I ran into a strange problem when I was trying to put the arcade cabinet together. I have an old PC with a radeon 9200 that I'm using to drive a signal over svideo to a 27" samsung CRT, but I noticed two problems last night. First, there were these static diagonal lines all over the screen, which were really visible when there was a dark background up. If I cranked the brightness I couldn't really see them as prominently, but at any level where the output from the computer looked decent, there were these thin greenish lines visible (probably about 1" apart, running at about a 15 degree angle up to the right). The other problem was a much louder than usual high pitched whine from the TV.

 

Anyone have any idea what's up with either of these problems? I did notice that if I plugged the TV in with no input on the svideo jack and turned to that input (or any of the other composite inputs actually) the lines would be visible with the adjustments I'd made to the TV, so I'm starting to think it's not the source.

[GreenMonkey]

I used to use s-video out for MAME all the time and never had any problems with my Radeon 8500.

 

Dunno. Got any more s-video sources around ?

[Magness]

Greenish lines sounds like video sync issues which could be the source, cable or the TV. To narrow it down, I`d check the cable first especially since standard S-Vid isn't a locking connector: make sure the cable is plugged in tightly on both sides and that the cable length isn't over 20ft (preferably less). If so, try replacing the cable and see if that helps - maybe with a better (plenum) shielded cable? If not that then, I'd agree with GM: try another S-Vid source and see if you have the same problem. If the TV has multiple S-Video inputs, try another one or try an S-Vid to composite breakout and see if you still get the green lines after converting.

 

Hope that helps...

[ChrisBardon]

So I think that the problem is the TV itself, since I'm still getting the lines showing up when there's nothing on the input. I spent a little time trying to get another svid source to work, but it turns out that for some reason my DVD player is refusing to output on anything but component (even after I switch the output to 4:3). Very strange. I did try the PC again though, and with some adjustments on the TV I managed to get the lines to an almost acceptable state. It meant bumping the brightness on the screen much higher than I would have liked (since I thought it looked pretty good at almost zero), but it means that I'm getting something that's at least partway decent. I might see if there's a way that I can adjust the image at the source as well to compensate perhaps. I'm also going to try another TV when I get a chance-there's another spare around that might be in better shape, so I'll give that a shot. In the meantime though, it's back to wiring buttons...

[Magness]

Good Luck man Hope it works out

[ChrisBardon]

OK, so it turns out that it was the TV's problem, since the second TV looks a whole lot better. No lines, so I can actually adjust it so that black shows up as black and not a washed out gray. Now the catch-the hole for the TV in the cabinet is 27" wide, but the case for the new TV is 27.5". Now the plan is to take the entire mame cabinet apart (again), and take a router to the sides to cut a 1/4" groove at the front so the front end of the case can fit. I took a look at the case, and there doesn't seem to be an easy way to take off some of the plastic and still keep it in the case. I'm also not really interested in taking the CRT out of the case, since those things carry a VERY high charge. All I'd need is to slip when putting it in, or worse, have someone reaching in back sometime and touch the wrong thing.

 

It'll be worth it when it's done though-I played around a bit with the old TV in the cabinet on the weekend, and it was pretty awesome.

[Magness]

Sounds awesome - post pics once its all completed, curious to see the finished product