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Ask HN: Tips for hacking a TV?

76 points fewgrehrehre | 1 comments | 16 Oct 24 03:44 UTC | HN request time: 0.205s | source

I've got a spare television lying around (specifically, a Samsung UN24H4500), and I thought it'd be fun to take a crack at seeing what I can do with it. The only hitch is that I've never really done any hardware hacking before, so I don't really know where to start!

Any tips and pointers would be much appreciated, in terms of common ways to search for and exploit vulnerabilities, or the exploitation of other televisions. Alternatively, if this is an absolute fool's errand, and the whole thing is locked down tighter than Fort Knox, a firm warning that this is not a good thing to dick around with over a weekend would also be appreciated.

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purple-leafy ◴[16 Oct 24 05:30 UTC] No.41855906[source]▶
Whatever you do, don’t touch the capacitors, especially if it’s an old TV, even if it’s unplugged. Could kill you. Old TV caps pack a serious punch (even when unplugged)
replies(6): >>41862027 #>>41866933 #>>41871123 #>>41877332 #>>41877889 #>>41878329 #
1. hagbard_c ◴[18 Oct 24 10:11 UTC] No.41877889[source]▶
That may have been true a long time ago in the age of CRT (picture tube) televisions but anything with a flat screen contains a bog-standard switching power supply with a bunch of 450V-or-so capacitors which will give you a nasty bite but not much more than that. In CRT sets it typically [1] wasn't the discrete capacitors which posed a problem but the CRT itself which was used as a smoothing capacitor for the HT power supply. The in- and outside of the back of the tube were (are) covered with a conducting paint (e.g. 'Aquadag' [2], a colloidal graphite coating) with the inside connected to the HT power supply and the outside connected to ground. That 'internal capacitor' can keep its charge for a long time. As to whether it 'can kill you' that seems to depend on a lot of factors ranging from the discharge path, physical condition of the subject and more. There are many reports on people getting zapped who describe it as 'a nasty jolt' but survivor bias means this is not what you should go by - just avoid getting zapped by discharging the tube.

[1] there are exceptions, e.g. older vacuum tube sets which used a mains-driven EHT circuit with discrete capacitors

[2] https://en.wikipedia.org/wiki/Aquadag