8CM7, General Electric, Medium-Mu Dual Triode Vacuum Tube - NOS - TESTED
The General Electric 8CM7 is a Medium-Mu Dual Triode vacuum tube of the 9-pin miniature type, featuring two dissimilar triode units within a single glass envelope. It was primarily designed for use in vintage television receivers that utilized a series heater-string arrangement. The 8CM7 is a controlled warm-up tube, which helps minimize voltage surges during the warm-up cycle in TV sets where multiple heaters are wired in series. In TV circuits, it was specifically intended for vertical deflection amplifier service, with one triode unit typically used as an oscillator and the other as an amplifier. Restorers of classic television sets and electronics hobbyists seek out these New Old Stock (NOS) tubes to maintain the authentic performance and reliability of their vintage equipment.
Part number: 8CM7
Brand: General Electric (GE)
Type: Medium-Mu Dual Triode (with dissimilar units)
Use: Vertical deflection amplifier/oscillator in television receivers, particularly those with a series heater string.
Condition: New Old Stock - NOS
Cross Reference: 6CM7 (identical except for heater ratings), Unknown
Tested - This tube has been tested with a B&K or Hickok tube tester. For NOS tubes we removed it from the packaging and tested it. Then returned it to its original box. The tube passed all tests that are applicable to this type of tube. The tube was allowed to warm for at least 30 seconds before testing.
This item is New Old Stock (NOS)
Vacuum tube in its original box
The box may be in rough shape and may have tape on it - PLEASE look at photo
May have re-labeled the box for clarity
The tube is in Excellent, New Old Stock (NOS) condition, appearing unused with a clean glass envelope and intact getter flash. The original GE box is in Fair condition, showing significant signs of age and wear, including tears, creases, and discoloration from storage.
8CM7, 6CM7, Dual Triode, Twin Triode, Miniature Tube, 9-Pin Tube, Vertical Deflection Amplifier, Vertical Oscillator, Vintage TV Tube, NOS Tube, General Electric, Series Heater String.
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