WHAT IT WILL DO No. 1—The Dyna-Quik Model 675 automatic punched card Tube Tester will check more than 99% of the TV tubes in general use. Tubes can be tested in an incredibly short time since only a minimum number of controls need be set. No. 2—The Model 675 will provide accurate results because it checks tubes for their Dynamic Mutual Conductance (Gm) in a true transconductance bridge. Diodes are checked for emission only, since they possess no mutual conductance. No. 3—Each tube is automatically checked for short circuits and leakage up to 1 megohm. These tests are made between the various elements of the tube and furthermore this test is made before the Gm measurement. No. -1—The Model 675 Tester will provide an indication of the probable useful life remaining in a tube by means of a special LIFE TEST. No. 5—Gas, grid contamination, or even obscure grid-to-cathode leakage are all disclosed by an exceptionally sensitive grid current check. This test will reveal as little as 2 or 3 microamperes of current in the grid circuit. No. 6—Each section of a multisection tube is checked separately. Therefore tubes can be checked and selected for balance between sections. This is convenient for selecting dual section tubes to be used in push pull circuits. No. 7—Semiconductors (rectifiers, diodes, and transistors) can be tested. Rectifiers cheeked for Forward-to-Reverse Conduction Ratio. Diodes for For-ward-to-Reverse Ratio. Transistors for Leakage and Gain.