Precision 640 tube tester manual
with three sets of tube data, reprint.

This is a digitally copied and enhanced manual for the Precision model 640 cathode conductance tube tester.  It has been copied from an original and is clear, clean, and easy to read.  It is printed on premium 24# paper with heavy covers and bound with a plastic comb.  No more struggling with unreadable photocopies!

It measures 8 1/2" X 11" with about 60 pages. Topics include:  features, operating instructions, service data, and schematic.  Also included are three sets of  tube data for the models 640 & 660: Coletronics tube data TRC (H2B), Coletronics tube data TRC (6-1-74), and Precision supplementary tube data TRC (GK) including obsolete type, special applications, foreign tubes, and an addendum to the TRC data (3-61) which includes American equivalents of foreign types.