#3 Atari 800XL New BASIC ROM + Video Mods

I dusted off my Atari 800XL restoration project to finally install a replacement BASIC ROM via an adapter from Retro Innovations. I also implement the video output mods covered in a very timely video by Adrian's Digital Basement.
Adrian's Digital Basement 800XL Video:
• Atari 800XL repair: Bl...
ROM Socket Adapter for BASIC ROM:
www.go4retro.com/products/23xx...
Atari 800XL BASIC ROM Images: (I used Rev. C)
atariwiki.org/wiki/Wiki.jsp?p...

[@christopherdavis5544]

C56 was fitted to early XL's to soften up the messy image from the RF modulator. It was removed in later revisions.
The colour pot needs adjusting to correct the too blue picture. There are utilities online to help.

[@prozacgodretro]

Protip! Wipe down the solder wick with some extra flux (I think they tend to have flux in them) really helps just suck the solder out of a via!

[@Adam_Lyskawa]

This capacitor was Atari's "hardware anti-aliasing" ;) It worked in horizontal direction only, but back in the days we played games on 8-bit computers - in the highest resolution the pixels were not (that) visible. So - people who know 8-bit graphics only from emulations or modern LCD displays - it's not how it looked back in the days. On a TV (most users had) a pixel was just a fuzzy dot.

[@blackterminal]

Using these computers on a lcd is not how it should be. Crt is the way.

[@kevin34ct]

When working with bare braided wires, tin the leads. It will save you a lot of aggravation. Also the best mod for video is the Sophia2DVI. With an 800XL it's just pop out the GTIA out of the socket and insert the mod. There is even a longer cable and cover to replace the parallel port cover with the DVI connector. I just took out my RF modulator and cut a hole in the case to put the DVI connector in.

[@fourthhorseman4531]

Just removed that cap on my 800XL and definitely saw improvement in the image as a result. Thanks for passing along the tip!

[@buriedbits6027]

14:00 In your video demonstrating the repair of an Atari 800XL, the removal of a capacitor resulted in a sharper image when connected to a flat screen using an RCA video plug (composite connection). Conversely, having the capacitor in circuit softened the image. I hypothesize that Atari deliberately invested in this additional part, despite it causing image blurriness on LCD screens, because CRT televisions dominated the market at the time. As a consumer computer designed for CRT displays, Atari might have opted for this capacitor in circuit, accepting the slight blurriness for better display quality on CRT tubes. This theory suggests a deliberate choice made by Atari to optimize display output for the prevalent technology of that era.

[@blackterminal]

I would not be removing parts.

[@buriedbits6027]

Great! What an improvement.

[@waltciii3]

Flip your luma chroma on the board so the cables match better.

[@gamedoutgamer]

Well done! Congrats! The comparison of resistor connected vs unconnected was great. Some editing of your video to quicken the pace will improve it's watchability if that's a word. =) Please do more A8 vids.

[@gregsgeekery]

Thanks for the feedback, Much appreciated. Still pretty novice at editing, but yeah a lot of the soldering and stuff could be cut or fast forward. I'm thinking to try to address the jail-bars (although they are pretty minor). As @adriansdigitalbasement mentioned, you can supposedly remove another capacitor, but it has a downside. I may experiment to see if I can overcome that.

[@gamedoutgamer]

@@gregsgeekery ​ For the amount of effort and cost (none) what you did is great and acceptable. There is however the Super Video 2.0 (or higher) community created guide to improve video but I think what you've done is ideal. Alternatively there is a post by Wilheim - "In my case, I replaced R56 with a small transistor circuit similar to the chroma signal extraction from the xe models. It improved the image a lot and I didn’t have to add a switch for composite video." So he probably also removed C54 because that's what improves video after removing C56 but disables composite. The topic on AtariAge is forums atariage c m topic/326587-800xl-s-video-fix/

[@blackterminal]

There is a risk of the old key plungers snapping when you remove keys.

[@GerardPinzone]

Is that Rev B Atari Basic (what came with the XL) or the newer Rev C?