Atari 800XL, no color from composite output

[cyco130]

Hi everyone,

 

I've got a PAL 800XL with the (AFAIK) newer XLF board. I can't get any color from the composite output with an LG flat screen. The cable itself that I made seems to work. I tried adjusting the color trim pot but it didn't help (except changing the pattern of the vertical lines I'm seeing).

 

I can't try the RF output because I don't have a cable for it.

 

I would appreciate any ideas on where I should start looking.

[cyco130]

Hmm, I dug up an old PCI Tuner card and installed it in my computer. Color works as expected. Maybe it's a problem with my TV.

[flashjazzcat]

Hmm, I dug up an old PCI Tuner card and installed it in my computer. Color works as expected. Maybe it's a problem with my TV.

 

Is the TV from PAL-land? My PAL 1084-S monitors will not sync to NTSC Atari colour.

[spookt]

Not sure about the XLF boards but aren't PAL 800XLs missing the chroma signal on the monitor port? I've always had to add a resistor and a wire to get colour on mine.

[cyco130]

Thanks everyone!

 

I don't know what the problem was but resetting the TV settings to factory defaults brought the color back. (Yes, the TV is from PAL land and I was using the composite output, not separate luma and chroma).

 

By the way the XLF boards do have the chroma output connected (at least the one that I own does). That brings me to my second question:

 

I made a cable that connects the Atari's monitor outputs to audio, composite and s-video (luma + chroma) inputs of my TV. The composite output is fine, it's a bit blurry but I think that's to be expected and I'm not too picky. S-video output seems to be sharper but I'm seeing these jiggly vertical lines with all my Ataris (including the ones with no chroma) as you can see in the attached photo.

 

I've completely disconnected the RF box and later removed the C56 cap hoping for a quick and dirty fix but I didn't notice any improvement. Any ideas?

 

Edited February 7, 2014 by cyco130

[cyco130]

Bump!

 

Sorry to do that but does anyone have any suggestions about my issue in the previous post?

[Rybags]

You also get that on CRT, it's just that it's much less noticable because the pixel definition is usually nowhere as sharp as LCD.

[cyco130]

Thanks Rybags.

Hmm, the lines are barely noticeable with composite output too. How much would it help if I try one of the SuperVideo type mods? And which one is the "state of the art" for PAL 800XLs currently?

[flashjazzcat]

I used to spend a lot of time fiddling with these kinds of "vertical banding" issues before I stuck VBXEs in all my frequently used machines and stopped worrying about it... but way back when I first dug my 65XE out of storage, a reasonable solution was a (then) readily available s-video cable on eBay which had (IIRC) a diode in-line on the chroma pin. For reasons unknown, this really reduced the banding effect and (without much electrical know-how), I ended up experimenting with diodes and caps inside the machine. Unfortunately I can offer little insight on the whys and the hows, but I can say that the effect can be reduced or eliminated if you're prepared to mess with the video circuit.

Quite a good thread on it here, and there are many others if you do a search for "s-video" or "vertical banding".

[cyco130]

Thanks FJC!

 

I thought I've done enough searching in the forums but I couldn't come up with the magic words "vertical banding"