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Need advice/pics for 800XL video improvement

800xl s-video upgrade

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#1 suspicious_milk OFFLINE  

suspicious_milk

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Posted Mon Apr 8, 2019 7:34 PM

I picked up an 800XL in fantastic condition and added an Antonia CPU/RAM upgrade.  Sold it to a friend of mine, and then ended up getting it back :-)

 

It has pretty fuzzy video though.  According to this post:

 

https://atariage.com...-mod-for-800xl/

 

I'm going to

 

 

  • REMOVE C56 capacitor (if present). This will dramatically improve sharpness and "edge"-definition.
  • Lift C54 right-hand side, preferably by inserting an on-off switch (if you want to preserve composite out). This will almost COMPLETELY remove vertical banding (present on Luminance-Y signal).
  • Solder Chroma-signal wire from R67/R68 junction, to chroma pin in video port. This will enable the missing chroma-signal on the 800XL (the majority DO NOT have it enabled). No need for pick-up resistor (of any kind).

 

 

 

I'm skipping step 2, as no banding is present; it's just REALLY fuzzy and currently s-video outputs black and white only.

 

My soldering skill are improving, and I've a shiny new solder station arriving on my day off.   I guess I could easily do this with just schematics, but ...

It would be greatly appreciated if someone has pics of these simple finished steps  (I like pictorial verification, because I'm pretty new at this stuff still).   Any other advice on what to do while I'm in there?   Besides the Antonia, all my other work has been on XE models.  I put a UAV in my 130XE and if this doesn't work out, I'll probably buy another for the 800XL.

 

Thanks,

Thomas



#2 xrbrevin ONLINE  

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Posted Tue Apr 9, 2019 3:21 AM

you should only fit a switch if you want to choose between both s-video and composite. if youre happy with s-video, just desolder and lift the right-hand side of C54 and leave it disconnected

a drawing is here for reference - to show the locations of the capacitors. NOTE: not all 800XLs have C56

 

hope this helps!

 

 

Attached Thumbnails

  • 800xl svideo mod c56 c54 reference.jpg
  • 800xl svideo mod.jpg


#3 suspicious_milk OFFLINE  

suspicious_milk

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Posted Wed Apr 10, 2019 3:24 PM

Thanks for the pics ...

 

I've done

 

  • REMOVE C56 capacitor (if present). This will dramatically improve sharpness and "edge"-definition.
  • Solder Chroma-signal wire from R67/R68 junction, to chroma pin in video port. This will enable the missing chroma-signal on the 800XL (the majority DO NOT have it enabled). No need for pick-up resistor (of any kind).

The composite video is still horrible, no improvement at all.   The S-Video (now color!) Loookss spectacular.  The color pallete is very wonky though (lots of magenta's)... grrr

This 800xl was/is my experiment machine, but still frustrating.   I'll do some digging.   Maybe I'll just pull out the Antonia and put it an XE if I can make it fit.

 

Edit:  adjusted pot, the color palette is fine now


Edited by suspicious_milk, Wed Apr 10, 2019 3:33 PM.


#4 DrVenkman OFFLINE  

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Posted Wed Apr 10, 2019 3:36 PM

Until I put a UAV board into the machine, here's what I did for m daily-driver 800XL a few years ago:

 

Bryan's Quck & Easy Video Upgrade for 800XL

 

For the minimal level of effort, the results were very good.  



#5 suspicious_milk OFFLINE  

suspicious_milk

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Posted Wed Apr 10, 2019 5:57 PM

Thanks.  Since the S-Video looks so good, and I don't use composite much, I think I'm going to leave well enough alone for now. 

 

I had good results with a UAV board in my 130XE so may go that route with this 800XL later.  As it stands, I'd say the 800XL's s-video is superior to the 130XE with UAV.







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