Re: 120 and 180 line viewing
Posted: Mon Jul 28, 2014 10:12 pm
Steve Anderson wrote:*With head in hands* Here we go...first, the two versions you've posted in this tread are different, not just in layout, but electrically. They are both different to the original PT version (which is expected)...and the scrap view on the VRAT forum is different again to all. Or am I all confuzzled again?
Think you may be - can't blame you though. My own two circuits should be electrically identical. I've just checked again. One likely point of confusion could be a 22K on the earlier diagram that (from its position) looks like an anode load resistor but actually is part of the frame pulse network! Thus the dire need for a re-draw...
Steve Anderson wrote:Now the one that looks the most sane to me is 'redrawn_current.gif', your previous post. The one on VRAT looks OK too.
These are very similar. The only differences to the sync separator: a grid leak resistor I added to V14 and some changed component values.
Steve Anderson wrote:However, from what has gone before you don't appear to have a sync separator problem, just a flyback one. It's taking too long to get back to the top of the screen, the triggering seems OK. So I suggest leave the separator alone and try the time-constant mod I suggested earlier, VR5,R49 & C43. i.e. leave VR5 as is, return C43 back to original and increase R49 to 5M6, possibly 4M7 or 6M8.
Will do!
Steve O