• spankysalmon@fedinsfw.app
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      4 days ago

      That’s just basic electronics stuff. It doesn’t take a terribly large charged capacitor to zap you dead. IIRC, there are some high voltages in CRTs, but if you know how to discharge caps and to never ever work on electronics while plugged in (especially anything AC or DC over even 12v running), you’ll be fine.

      Making them, however, is a whole additional technical and mathematical set of skills.

      • over_clox@lemmy.world
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        4 days ago

        The outer envelope layer of a CRT itself is a capacitor, and depending on the tube size, can hold ~13,000 to ~25,000 volts. What makes it worse is that you can properly discharge the tube, completely remove it and put it on a storage shelf somewhere for months, then come back to it and the motherfucker done managed to recharge itself from the fucking atmosphere!

        • vorpuni@tarte.nuage-libre.fr
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          4 days ago

          Any sufficiently big capacitor does this and that’s why you short them out for storage unless you want to die.

          The biggest ones I worked with were 75 kg slices of stinkiness when they leaked and had to have two separate loops of wire on the terminals for safe disposal.

    • adjectivenoun@lemmy.world
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      4 days ago

      It’s really not that dangerous. There’s a big capacitor called the flyback capacitor which can store a deadly amount of energy. You disconnect the power (obviously) and then discharge that cap and everything else is relatively safe. To discharge a capacitor, bridge the leads with an electricians screwdriver. If you don’t like sparks, hold a resistor with pliers between the two leads. (It will go slower but also get hot AF.)

      • f4f4f4f4f4f4f4f4@sopuli.xyz
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        3 days ago

        The capacitors are the same ones that are in every desktop PC power supply.

        The flyback is a complex transformer with the thick cable sending the high voltage to the tube’s second anode.

        The CRT itself can act like a giant capacitor. Eventually they figured out how to bleed the charge out when the TV is off.

        1990s-2000s tubes: I discharge but don’t worry too much. 1980s-1990s tubes: I discharge several times, over the course of an hour or two. Those Sanyos that Nintendo used hold a nasty charge that comes out with a big SNAP!

        • adjectivenoun@lemmy.world
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          3 days ago

          The way they bleed the charge off when the TV is powered off is through a very high resistance resistor. This works perfectly well most of the time, but those resistors can and do fail. The same is true for microwaves, which also have flyback circuits. Always treat these things like the bleedoff resistor has failed.