Here is a Schematic I worked out and built a Clone Copied from my original Supro 6420
(http://i282.photobucket.com/albums/kk243/supro66/SUPRO6420-schamitic.jpg)
NOTE----SET---YOUR---PRINTER--TO---LANDSCAPE--TO--PRINT--THIS
MY TUBE AMP SITE
http://www.geocities.com/insp/SUPRO6420.html
Some place on this site I saw a Turret Board layout of this
I will post it here if someone finds it