Super Video 2.1XL
From the pen of AC's "occasional columnist" Ben Poehland comes the final, gutwrenching word on cleaning up video problems in all the XL-series computers, as The Alchemist brutally reveals the scandalous acts of the Sunnyvale Butchers. Clean video at last for the 600XL, 800XL and the 1200XL owners!
Monitors
For testing purposes throughout this project I used the following monitors: Apple A2M2010 green-screen monochrome (luma interface), Commodore 1902 and 1084 (luma-chroma and CV interfaces), Amdek Color 300 (luma-chroma and CV), Magnavox 1CM135 (luma-chroma and CV), and a Magnavox RD0510 5" portable color TV with direct video input (luma or CV interface). The Apple monochrome monitor of course gave the cleanest display: crystal clear and razor-sharp using the CV Disable switch. Performance among the various color displays varied tremendously. The Commodore monitors, with their fine dot-pitch, gave the sharpest color images, while I judged the Magnavox 1CM135 slightly less sharp than the Commodores. The coarse dot-pitch on the Amdek rendered poor resolution, but color saturation on the Amdek is superb even with the pallid color output of the upgraded 600XL and 800XL. Performance on the little Magnavox TV didn't compare to the monitors due to the tiny screen and really coarse dot-pitch. You could run color games on it for demo purposes. Using only the luma output and turning off the color controls, you could do 40-column AtariWriter word-processing on it if you don't mind the tiny letters.
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NOTE: The Magnavox Monitor listed above is most likely no longer available. However, there has been an ad in Nuts & Volts magazine for a 13 inch Composite/RGB/CGA/EGA monitor for $50.00 plus $12.00 shipping. These are used but listed in good condition. Might be worth taking a look at. Contact General Science & Engineering @ 716-338-7001 |
Coda
While I was writing up this article a long-awaited 1450XL finally arrived. With considerable excitement I connected it to my test monitors and fired it up. Horrors!! The display was as bad as a stock 1200XL! With no schematics, board diagrams, or manuals of any kind, and an opaque circuit board that you can't follow traces on by holding it up to strong light (the 1450XL employs a multilayered board), reverse-engineering the video circuits is a formidable task. I took time away from this article to hack it. I only got bits and pieces, but that was enough. The mono circuit has a 390-ohm output impedance (groan!), and there's a capacitor sucking away all the high frequency response from the mono output, the mono output is full of color clocking trash, I can't find the chroma... sheesh! The long arm of the Sunnyvale Butchers reached out to poison even the products that never made it to market.
Thanks for the tainted legacy, Atari.
Copyright © 1993
Atari Classics
1161 Bay St.
Alameda, CA 94501
