GameSX hereby and officially recommends the rather excellent free schematic making program BschV3. Check it out here (http://www.suigyodo.com/online/e/),
To go along with this app, I created a BschV3 PC Engine component library (http://gamesx.com/grafx/NFGlib.LB3).
(http://gamesx.com/grafx/PCE-lib.png)
Updates and additions to thie library will be posted in this thread.