eli5: How does smacking a TV make it work again?

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Sometimes when TVs show nothing but fuzzy static, in the correct channel, people can hit them and it ‘fixes’ it and displays the correct image, how does that work? What’s initially wrong and then what gets fixed?

I’m not sure if it happens with new TVs though.

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Feom whag i’ve been told, the problem is usually a short circuit somewhere in the device or somethign aling those lines.hitting it has a chance of reconnecting the wires, so it wouldnt fix permanently it, but be a temporary job.

Absolutely still does it on modern stuff, just the other week i had to smack my sister’s phone because it had a purple screen of death, instantly worked again after 3 osh hits. Probably does it for all devices tbh

Generally a bad solder joint, for example on a cap. Whacking the set makes the connection, then expansion due to heat generally keeps said connection i till you switch it off and it all cools down.

It doesnt. It was pure matter of chance in the old electronics that had vastly different manufacturing processes than it has now. In the old days you had bulkier components and much more movable parts, and sometimes, they would slide a bit out of their positions over the time or some connection would get loose. Smashing it would sometimes, way less than it is shown in TV shows/cartoons, put it back to place and re-eastablish the connection.

A television used to be made with tubes in them. Now everything is on a motherboard.

So smacking a television would even make the tube connect or start up.

You could take a tube out of the television yourself and go to the store and there was tube testers you could put them in to tell if they still worked.

It is called “Percussive Maintenance”

Before the mass availability of integrated circuits, electronics used many more components, much bigger components with much pigger solder points.

As time goes forward those connections can oxidate and stop conducting. Smacking something can scrape off some of the oxidations and make the conduct again. HOWEVER over time the repetitive scraping can eat away the contact as a whole and dislodge conponents, broking the thing itself

If you have to smack your TV to fix it, consider it broken, smacking is just a bandaid… The more you hit it the more it is going to broke, until it is broken permanently

Todays technology uses ever so smaller and more integrated chips, if something breaks it is most probably inside a chip, hitting it doesn’t help it is burned out…

Sweet! Thanks!

dust and grease can cause micro shorts that interfere with the electrical signals.

a good smack can shake some of that loose and allow better images without the noise.

Thanks for the answers everyone!