486 case LED display jumpers

Teo Zenios wrote: There's a reverse-engineered partial circuit on VOGONS: http://vogons.zetafleet.com/viewtopic.php?t=10780&sid=f80bc89c785100a9d… If you could put a photo of the PCB on one of those photo-sharing sites (say, Photobucket?) and post the URL, I might have the paperwork kicking around in one of my folders. "TH99" (Total Hardware, 1999 edition) might also be worth a look, copies of that are kicking around on Google. Usually the jumpers are laid out in a tesselated "T" pattern, a bit like this: 1 2 3 4 Valid jumper positions are 1-2, 2-3, 2-4 or no jumper. If memory serves, 1-2 is "on with TURBO on", 2-3 is "on with TURBO off", 2-4 is "on all the time", no jumper is, well, segment not lit. Which segment is tied to which jumper cluster depends on the specific display in use. Of course, you get boards designed by folks who thought they were being clever, which end up with a layout like: 1 a 3 b 4 c 1 d 3 (or something like that, I've probably got it at least a little wrong) Letters = segments; 1,3,4 = supplies. You could probably reverse-engineer one with a multimeter in about 25 minutes. Remove all the jumpers, Set TURBO off, find all the lines that are high, repeat with TURBO on. From that you'll be able to figure out which pins are always-high, and which depend on the state of the TURBO input. Anything that stays low is a segment. If dealing with a common-anode display, reverse "high" and "low". -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/