atari8warez Posted August 31, 2012 Share Posted August 31, 2012 (edited) Quick question. I've just got a 1200XL yesterday (my first and only one), just checked the SIO for +5v and it's there, I remember reading that (and even on this thread) 1200XL lacks the +5v on SIO pin 10. Mine doesn't and it's not modded in any way, so am I missing something? (or rather have a nice extra on mine). The mobo is a Revision A. And if it did lack the +5v how did it work with a 1050 drive? As far as i know 1050 needs the 5v coming from pin 10 (or was the 1050 introduced after 1200XL) Edited August 31, 2012 by atari8warez Quote Link to comment Share on other sites More sharing options...
+Stephen Posted August 31, 2012 Share Posted August 31, 2012 I believe the issue is that although the voltage is there, it is severely current limited. Inside the 1200XL, you will want to jumper R63. Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted August 31, 2012 Share Posted August 31, 2012 SIO devices need to see +5v on the Ready line. This tells them that the computer is turned on. Some devices are actually powered by the Ready line, which will work on all systems with the exception of the 1200XL. R63 in the 1200XL limits the current on the Ready line to just a few milliamps of current - enough to pull Ready high, not enough to power a circuit. If you will be using things like P:R Connection or MPP printer interfaces on a 1200XL, you need to replace R63. Yes, you will measure +5v on the Ready line, but you can't power anything useful with it. Bob Quote Link to comment Share on other sites More sharing options...
atari8warez Posted August 31, 2012 Share Posted August 31, 2012 (edited) SIO devices need to see +5v on the Ready line. This tells them that the computer is turned on. Some devices are actually powered by the Ready line, which will work on all systems with the exception of the 1200XL. R63 in the 1200XL limits the current on the Ready line to just a few milliamps of current - enough to pull Ready high, not enough to power a circuit. If you will be using things like P:R Connection or MPP printer interfaces on a 1200XL, you need to replace R63. Yes, you will measure +5v on the Ready line, but you can't power anything useful with it. Bob Thanks for the great info, so the article I've read was kind of misleading as it said "lacks the +5v on SIO 10", now everything makes more sense, so R63 has to go By the way Bob, i just did your 3 point video mod (plus the chroma) and the video looks much better now, not quite as good as the stock 130XE but good enough not to bother with the rest of the Clearpic (second edition) mod. Thank you for the very useful tip. Edited August 31, 2012 by atari8warez Quote Link to comment Share on other sites More sharing options...
atari8warez Posted August 31, 2012 Share Posted August 31, 2012 @Bob1200XL Oh I just realized your 3 jumper mod includes the R63, so it's gone already Quote Link to comment Share on other sites More sharing options...
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