A800 S-Video output: Is it known for being overbright and washed out?

[iainjh]

Hi

 

I have a few 800 XL's and even on unmodded composite they look pretty good on my LCD TV. Blacks are generally blacks and the composite pic isn't too bad. However, my original 800, using S-video, looks way too over bright and the colours consequently look washed out as well. Blacks are too bright, and look grey.

 

I can 'address' that by turning down the brightness on my TV about 15% but then every other bit of kit I have is way too dark.

 

My questions are then -

 

a) is this a common issue? I've searched and googled atariage without result

 

b) if so, is there a known /and easy(!) fix than can please be recommended? If there is, if I have to take it apart to fix it, are there any other video mods that can be recommended at the same time?

 

c) surely its not my leads..I got it from atarivintagecomputers on ebay and with my C64 lead had every reason to be happy about those..

 

TIA for any help!

 

Iain

[+bob1200xl]

I think the video is designed to drive a 75 ohm load at the monitor end - most TVs don't have terminators. My Teknika monitor has switchable termination, which was probably the norm back when Atari was doing this. Without the resistors, the input is overdriven - 130Xes are even worse than 800s. I just wire in a 75 ohm resistor to ground on the LUMA and CHROMA signals in my s-video cable. Works much better. (don't really need to terminate CHROMA, probably) Of course, some monitors don't like the added resistor so it's best to use a switch.

 

The reality is that the Atari video is non-standard for the most part. The 'porch' levels are wrong and it isn't interlaced at all. Digital TVs and monitors have to normalize and decode the video before they digitize it - a tough job with the Atari format. If we can digitize internally and correct these problems, we'll see a much better graphic on the new displays. The LUMA is trivial... it's the CHROMA that's a challenge.

 

It can be done.

 

Bob

 

 

 

Hi

 

I have a few 800 XL's and even on unmodded composite they look pretty good on my LCD TV. Blacks are generally blacks and the composite pic isn't too bad. However, my original 800, using S-video, looks way too over bright and the colours consequently look washed out as well. Blacks are too bright, and look grey.

 

I can 'address' that by turning down the brightness on my TV about 15% but then every other bit of kit I have is way too dark.

 

My questions are then -

 

a) is this a common issue? I've searched and googled atariage without result

 

b) if so, is there a known /and easy(!) fix than can please be recommended? If there is, if I have to take it apart to fix it, are there any other video mods that can be recommended at the same time?

 

c) surely its not my leads..I got it from atarivintagecomputers on ebay and with my C64 lead had every reason to be happy about those..

 

TIA for any help!

 

Iain

[iainjh]

thanks for the info! now to decide what to do and when..

 

-iain

 

 

 

I think the video is designed to drive a 75 ohm load at the monitor end - most TVs don't have terminators. My Teknika monitor has switchable termination, which was probably the norm back when Atari was doing this. Without the resistors, the input is overdriven - 130Xes are even worse than 800s. I just wire in a 75 ohm resistor to ground on the LUMA and CHROMA signals in my s-video cable. Works much better. (don't really need to terminate CHROMA, probably) Of course, some monitors don't like the added resistor so it's best to use a switch.

 

The reality is that the Atari video is non-standard for the most part. The 'porch' levels are wrong and it isn't interlaced at all. Digital TVs and monitors have to normalize and decode the video before they digitize it - a tough job with the Atari format. If we can digitize internally and correct these problems, we'll see a much better graphic on the new displays. The LUMA is trivial... it's the CHROMA that's a challenge.

 

It can be done.

 

Bob

 

 

 

Hi

 

I have a few 800 XL's and even on unmodded composite they look pretty good on my LCD TV. Blacks are generally blacks and the composite pic isn't too bad. However, my original 800, using S-video, looks way too over bright and the colours consequently look washed out as well. Blacks are too bright, and look grey.

 

I can 'address' that by turning down the brightness on my TV about 15% but then every other bit of kit I have is way too dark.

 

My questions are then -

 

a) is this a common issue? I've searched and googled atariage without result

 

b) if so, is there a known /and easy(!) fix than can please be recommended? If there is, if I have to take it apart to fix it, are there any other video mods that can be recommended at the same time?

 

c) surely its not my leads..I got it from atarivintagecomputers on ebay and with my C64 lead had every reason to be happy about those..

 

TIA for any help!

 

Iain