Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!ittvax!bunker!chuck From: chuck@bunker.UUCP (Chuck Heaton) Newsgroups: net.micro.apple Subject: hires_question Message-ID: <494@bunker.UUCP> Date: Thu, 9-Aug-84 10:31:29 EDT Article-I.D.: bunker.494 Posted: Thu Aug 9 10:31:29 1984 Date-Received: Fri, 10-Aug-84 08:18:34 EDT Lines: 24 Hi. Somewhere, I read about a simple modification to the Apple II (maybe also II+, IIe, or IIc) that effectively doubled the horizontal screen resolution for Hi-res graphics. The general idea was somehow tying the vertical (or horizontal ???) retrace signal to the 'bit' that selects page 1 / page 2. After making this modification, which I vaguely recall involved a single jumper and perhaps a single trace cut, the two 'pages' would automatically flip upon each vertical (I think) retrace. Although other effects are also possible, the particular effect that I was interested in was the above-mentioned doubling of the horizontal resolution for graphics. All pixels on one page are done with bit 7 low, and on the other page with bit 7 high (thus causing the half/pixel horizontal shift. I am not particularly hardware oriented, although I'm not a complete idiot either. If anyone knows how or can figure out how to perform this (possibly warrenty voiding - horrors) modification, could you please post it to the net or mail it to me directly. In return, I would be glad to submit (once working) source to replacement 6502 routines to allow Applesoft (or whatever) to take advantage or this capability (these routines are fairly easy to write). Thanks. Chuck Heaton