Philco rescued in Minnesota

[miniman82]

Update on this set.

It's been working pretty well for some time now, I gave all the pots a good cleaning and deoxit'ing so they aren't scratchy anymore. The pots up front are pretty cheap looking parts, it's easy to understand why these sets were 'price leaders'.

I got bored with it pretty fast though, and it had terrible 3.58 dot crawl in the Y line anyway. The dot crawl could probably be fixed with a few tweaks, but in the end I decided to go a different route- component video! Turns out the circuit is easy to change to accept component video, I repurposed the R-Y and B-Y demods so the pentode section acts to amplify the incoming signal. They don't provide enough voltage output though (or more accurately the incoming signal is far too weak), so an additional stage of gain will be required. Also the red info is getting to the pix tube too soon, so a short delay will be required to make everything line up. I'll probably unwind a Y delay from another set, till I end up with the right amount of delay.

So far I got it to display a color image with the mods I've made, so it's definitely possible to get working correctly. Only question at this point is to add a tube stage for R/B gain or use transistors? I figure varying the gain of the R/B signals will form a 'tint' control of sorts, and that would be easier to do with transistors.