: How does slapping an old tv make it work again?
In: Technology
Old TVs have old electronics. Some of those old parts are decaying. With that decay, there’s cracks in their wires and the things that connect the wires. If something (like oxidation/rust, or even just air) gets between those cracks, the wires stop working; hitting the tv can move things enough to get the something out of the way (or reconnect the wire over the cracks), which will let things work again.
Just like the filaments of a light bulb when it breaks and you hit it and they filaments pieces it touch each other and light again just the same way when you hit the side of the TV the valves that used to be the transistors used to and used to break and by hitting it they used to touch together again and work for a while until eventually I had to change the tube
Misalignment of parts and loose connections can be the source of issues. Sometimes hitting it realigns it (temporarily).
It doesn’t, other than through the means of confirmation bias. We don’t notice the myriad times that slapping it made no difference, just the ones where it appeard to magically start working again (masking that the slap had probably made the underlying problem worse).
In the early days of electronics, the solder used would grow tin “whiskers”. These whiskers would sometimes touch other components causing all sorts of problems. A hard smack would usually break these whiskers restoring normal operation.
https://nepp.nasa.gov/whisker/background/
Sometimes when the components heat up they just dont sit right in the various housings. A good slap can cause a vibration effect and they resit 🙂 . Blame heat
Hot-running components (such as resistors) gradually develop ‘dry’ solder joints due to thermal cycling (on-off, hot-cold). Sometimes, the dry joint will fail to make an electrical connection. Slapping the TV gives everything a mechanical jolt, and if you’re lucky, the dry solder joints will temporarily make a good connection again.
The primitive machine spirits found in older machines have a rite called “The Percussive correction ritual” which will cause the machine spirit to correct a mistake upon the application of a large physical force
Oh I’ve done that quite a few times.
On old CRT tvs there wss a pretty big coil that would generate high voltage to “draw” our the picture from a line at the center to take the full picture.
But making this voltage would be done with high frequency input to the coil.
And that would generate tiny vibrations. This over time would cause the soldering connections to the board to come loose and it would fail.
By smacking the cabinet you could shake it back in place for a while.
One dirty fix for this would be to take grandma’s big smelly hairspray and give it a good dose whwre the coil is connected to the board.
This would glue it back together for a few more years..
There’s lots of potential answers here… but I’m skeptical of most of them – at least for the cases that were happening often. Like, I’ve seen TVs and xboxes that turn on after a hit, and I think those may have the kinds of faults described in other comments (a shakey connection that was restored by hitting or heating, solder issues, etc..).. but I don’t think that was what was happening with CRTs, at least not usually.
I think that rather than “restoring a bad connection”, I think hitting the TV was temporarily causing something to lose power or connection, and thus we were effectively partially-rebooting it by hitting it. An old TV didn’t have a ton of “state” to reset, but it had some, and I think hitting it probably disconnected something that was important – like the electronics that maintained syncing to the vertical blank in the signal, or something in that kind of vein. Once the connection came back (because the disruptive shock had passed) that sync got a fresh new chance to match up right.
That’s fitting with the kind of issues I saw with TVs anyway. You could normally get some sense of the correct picture still being there; it wasn’t like the TV was blank or it felt like something had actually fully lost power or connection. Rather, it seemed like something had gone out of alignment, and that we were fixing it with kind of a “reset”.
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