Thanks Bob. A great deal of my career as an electrical engineer was spent using various drawing editors to generate schematics and PCB layouts and fun simulations, so this was familiar territory. The program I used was from a PCB fabrication company, ExpressPCB (
http://www.expresspcb.com/). They supply free software to drew schematics and lay out 2-sided PC boards. The software runs on a PC, or in my case , on a MAC running PC emulation software. I used this software a few years back to design my 'personal color wheel viewer' that I displayed at the ETF.
Steve McVoy used the same software to generate the schematic of Nick's prototype color TV, and Steve was kind enough to let me use his library of components he had created (tubes etc). This made my job a bit easier.
The software is easy to learn, and easy to use, so if any of you want to draw a schematic and/or lay out a PC board, check them out. They have a pretty extensive library of pre mace components, both analog and digital, and it is easy to create custom symbols and shapes in the schematic editor.
PS I noticed a bunch of errors in the reference designators on my posted schematic. Fixed 'em, will update them the next time I make my next update.