Manual for the Systron Donner TPDZ6-8 OV. Includes large 44"x34" schematic foldout. Schematics state "Trygon Electronics. Roosevelt, New York". Size: E, Code Ident No. 09206, 10403, Rev. J. Drawn: R. Cancel 2-16-70, Checked Greg D'???? (can't read the signature) 4-15-70. The revision notes are dates from 5-15-70 on revision A, through 6-28-74 on revision J.