magnavox roundie

[Jeffhs]

Originally Posted by timmy

i found no switch but then again i never leave any of my vintage sets plugged in. the only thing is a push pull switch next to the tuner that says auto- push and i have it pushed in thinking that will stop the instant on.

One way to defeat the instant-on feature is to remove the diode across the TV power switch. This diode will be located on the back of the switch and connected directly in shunt with it. If it shorts due to, for example, lightning strikes, your TV will remain "on" permanently; the only way to shut it off will be to unplug the power cord from the AC outlet. Instant-on for televisions was popular in the 1970s, but later in the decade when energy conservation became the watchword in America, the feature was eliminated.

There could be a switch on the rear apron of the TV chassis to defeat the instant-on feature, if your set has it. If so, set the switch to "off" and the instant on feature will be disabled until or unless the switch is set to "on" again.

The previous poster could be correct as to the "auto" switch on your TV's control panel being the defeat switch for automatic fine tuning; in fact, if the switch is near the tuner, it may well be the AFT on/off control. I would try this: deliberately mistune the channel you use for your converter box or cable box output until you get colored "worms" on the screen, then pull out the switch near the tuner. If it is the AFT switch, the picture will clear immediately.

BTW, you are very wise not to leave your vintage TVs plugged in when they are not in use; even with the power switch set to "off", the power is not entirely disconnected from the set since most of these switches are single-pole single throw, meaning one side of the line will always be connected. Some AC/DC radios and televisions are even worse, as one side of the line is directly connected to the AC line -- meaning there is a 50/50 chance of inserting the line plug in the socket such that the chassis will be "hot" with the full line voltage.

Moreover, after 40 years or more (this is especially true of very old antique electronics), problems can and very often do develop, stemming from such things as leaky or dried-out capacitors (especially power supply filters), resistors drifting off value, and the like. Leaving a vintage TV or radio plugged in, even if it is not switched on, can be a potential fire hazard if a component should short and, for any reason, the fuse does not blow. Selenium rectifiers are particularly dangerous in this regard, especially very old ones; they can short without warning and release a gas that smells like rotten eggs. It is for this reason that it is recommended to replace old, obsolete selenium rectifiers with modern silicon diodes whenever possible. If you take this route, be sure to add a dropping resistor in series with the diode; this will ensure that the voltage at the output of the silicon will be equal to (or very close to) that of the original selenium stack.