Atari 800 RF Good, Composite Bad

[+fimbulvetr]

I just picked up an Atari 800 in very nice condition. We used to have them at my school in the early 80’s, and I’ve wanted to get one for years. Anyways, I have a video issue with it ... the RF output is nice and clear, but the colour is off and there is ghosting in the composite output. I’ve tried three different screens... an LCD and two different CRTs, and I know they all work fine on composite with all my other 8 bits. Anything I should start looking at? I’ve disassembled the machine, and everything looks pristine inside. 

 

Composite:

 

 

RF:

 

[+Nezgar]

Looks like you've connected the luminance signal, not the composite signal to your monitor. Check the pinout of your cable. How many connectors come off of the monitor DIN jack? A stock 800XL has Luma, Composite, Audio, Ground, with chroma not connected.

[+fimbulvetr]

It is an original 800, no XL

[+Nezgar]

14 hours ago, fimbulvetr said:

It is an original 800, no XL

Right. So chroma should be available, along with composite. It depends which pins your cable connects to then.

 

[+fimbulvetr]

And that would explain it! My cable has pin 1, 3, and 5 connected to the three RCA connectors.

[+fimbulvetr]

In my feeble defence, the cable came with the yellow lead “helpfully” hand-labelled as “composite”.

[+fimbulvetr]

Cable rebuilt, now it works perfectly. Thanks!

[+Nezgar]

If your monitor has S-Video in by chance, you can get an even better picture by adapting the luma+chroma pins to an s-video mini DIN connector / cable.

[Mclaneinc]

No feeble defences in here, we can all get caught out with pre built cables.....Watch out for cables made for the C64 being given with Atari's, cables that are meant for a Commodore monitor with Chroma and Luma on..

[+slx]

...and cables made before the "yellow is composite" standard was established. 

[+fimbulvetr]

2 hours ago, Nezgar said:

If your monitor has S-Video in by chance, you can get an even better picture by adapting the luma+chroma pins to an s-video mini DIN connector / cable.

Good idea, I may give that a try.

 

49 minutes ago, slx said:

...and cables made before the "yellow is composite" standard was established.

I ran into that issue with my ti99... I didn't realize that the ti has +12v on pin one of the video socket, and used an aftermarket "universal" cable... good thing I didn't plug the hot wire into my monitor, but I had been using that cable for a number of years and wasn't always that careful about plugging it in as the colors weren't standard so I would play guess which wire is composite.  

[+slx]

10 hours ago, fimbulvetr said:

I ran into that issue with my ti99... I didn't realize that the ti has +12v on pin one of the video socket, and used an aftermarket "universal" cable... good thing I didn't plug the hot wire into my monitor, but I had been using that cable for a number of years and wasn't always that careful about plugging it in as the colors weren't standard so I would play guess which wire is composite.  

Scary. I usually rely on that buzzing sound when plugging video into an audio socket but then I only use Ataris (and occasionally Commodores). Probably a good idea to put some tape or P-touch labels or a drop of paint on the cable before it's too late. 

[Mclaneinc]

4 hours ago, slx said:

Scary. I usually rely on that buzzing sound when plugging video into an audio socket but then I only use Ataris (and occasionally Commodores). Probably a good idea to put some tape or P-touch labels or a drop of paint on the cable before it's too late. 

 

I must admit I've done the same thing but as stress and age started to muck up my memory a little I did indeed start to label everything..Thankfully my late old friend Bob was a fan of Dymo stuff so saved me some time and effort (and wrongly plugged in cables  ) 

 

Paul.

[+fimbulvetr]

6 hours ago, slx said:

Probably a good idea to put some tape or P-touch labels or a drop of paint on the cable before it's too late. 

Yep. As soon as I found that out it was dealt with.