osiweb.org

Ok, soon I'll go look at this again but the way I remember what I saw: Looking at the middle of sheet 4, VAS/ needs to go low to create the 3us pulse from U4B. I had thought that was what created the "front porch" part of the horiz sync. VAS/ won't be generated unless the address bus A11-15 hits the...

Thanks for the reply Steve. I've worked on this a little since the original post. Managed to pick up a TI 465 o-scope on craigslist :) The issue is more fundamental than I had first thought. I backed out the changes I had made back in the '70's and still not getting proper front porch or sync on the...

First hey, it great to find this group! So I'm trying to get my old C8P DF running and having video problems. It seems that someone (me) modified the video board around 1978 or so to get the V and H sync and video to tap into a B/W tv so I could skip the modulator. But now I'm trying to use the comp...