For sale is reprint of TM 11-1209, Precision 920P tube tester. Dated November 1944. Enlarged to 8.5×11″ from original 6×9″. Includes 2 11×17 Circuit Diagrams.
Description taken from manual: “Precision model 920P tube and set tester ( Test Set I-157-A) is a push-button-operated radio tube tester combined with a rotary range-selector system for obtaining measurements of a-c and d-c voltages, resistance, decibels and d-c currents on 33 ranges. The instrument also provides a direct-reading test for batteries, a test for pilot lights, and a system for obtaining qualitative analysis of mica, paper and electrolytic capacitors. The tube-analyzer circuit of this instrument makes use of a special testing system to check in one operation the two most important electrical characteristics of a radio tube, namely, mutual conductance and cathode emission. An automatic, interlocking, push-button element selector, incorporated in the analyzer, provides for simplicity of operation, visible filament-continuity testers, quick interelement short checks, cathode leakage checks, and rapid location of all tube elements for the application of the individual test voltages.”