THE GREAT MULLARD MAGIC BLOG — women valve testing

After passing the knock test, valves were passed to the main test bench and plugged into a test board where a specially designed  eight position switch  applied successively, appropriate voltages such that values were obtained for the following parameters: - Heater current Cathode current Control grid current Screen current Anode current Total emission Mutual conductance ( at 4 - 7 points on the characteristic curve dependant on valve type) Inter electrode insulation for all electrode combinations Only those valves whose performance fell within specified limits were then passed into "Factory Stock."  In the photograph below we see Enid Barribal testing...