For sale are reprints of Jackson 648 Tube Tester User Manual and Tube Test Data.
User Manual is 2 pages long, manual was retyped as original was in very bad condition . 70 pages of additional tube data is included. 17 page Special Tube Test Data form SP648/11 dated 5/64, 6 page Data Supplement SP648-2, 18 page Tube Tester Data dated March 1975, 9 page Special Tube Data with 1 page August 1975 supplement. This manual includes many tubes not on tester’s roll chart.