[Jeffhs]

Doug (drh4683),

That is exactly why I never liked the "instant-on" feature of many early '70s TVs. As you noted, it takes hours off the lives of the tube filaments and weakens the CRT a lot, once the set has been constantly on for a few years. Another reason I didn't care for instant-on is that it could be a fire hazard, as the tube filaments in sets with this feature are on around the clock--whether or not the main power switch is on (in other words, the set is never completely off unless one physically unplugs it from the wall socket). Yet another reason I did not like instant-on is the fact that lightning strikes near the power line to which the set is connected would often damage (short) the instant-on diode, which is connected directly across the main switch. With the diode shorted, it is now impossible to turn the set off with the power switch. The only way to turn off the set in this case would be to pull the plug. I heard of a lot of people who just left their sets in that condition when the diode shorted, or else if they knew how to do it, they would take the back off and cut the diode out of the circuit. The TV worked just as well without the diode as with it.