A question about when a projector is turned ON but there is no video signal, i.e. the screen is blank(black) Does this damage the CRT's or reduce their life?Does it stress any other components within the projector in this state?
In general, no. Tubes wear a fraction of the rate in the standby mode (when no light is emitted from the tubes), and I have had many projectors in with 30K + hours with the original tubes still being in good shape.
the G2 is the second grid that the electrons meet after have left the cathode and the first grid (G1).
The cathode (kept continously warm), has a continous, steady voltage level (let's say 140V). A first grid is mounted immediatly after the cathode, and biased very close to 0 V (ground).
If the voltage drops on the cathode, the difference in voltage between it and the anode voltage (34 KV), allow the electrons to win the first barrier (G1) and start their path, oriented toward the anode zone (close to the frontal surface). The G2, biased with some 800-1.2 Kv, regulates the electrons flow in a very fine way, allowing the tuning of the color balancing and level (at the low brightness levels) and the black "threshold".
You could find other 1 or two grids, on the tube, after them... it depends on the tube drawn project, and the usage of the electrostatic focus.
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