Hickok Model 540 Dynamic Mutual Conductance Tube Tester Manual Sorry, this product cannot be purchased. $8.99 Category: Hickok Description Description For sale is reprint of Hickok 540 Tube Tester manual. Manual 7 pages long and includes Circuit Diagram. Manual comes with 4 pages of Ballast Tube Data, Part list and Operating Instructions. Manual is dated 1944. Related products Hickok 388 388X CD In-Line Tester Manual $11.99 Read more Hickok PS-503 Solid State Regulated Power Supply Operating Manual $8.99 Read more Hickok Model 677 Oscilloscope Operating Manual $9.99 Read more Hickok Model 691 Heterodyned Marker Adder Operating Manual $9.99 Read more