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I've heard many times warnings about opening up CRT TVs on your own, because they contain scary old capacitors full of scary electricity, ready to zap your heart from you just looking at them.

But I asked around and there are no TV repair shops that deal with CRTs anymore here. Which is insane since these are the proper TVs that produce the dream-like, magical picture quality impossible to re-create on any modern TV regardless of price.

If I look with a flashlight inside the little gaps on the top and back of my big ol' 28" CRT from 1989, I can see that it's full of dust. This feels like a fire hazard, and just generally bothers me on a profound level. I just wish I could remove it somehow.

How dangerous would it really be for me to turn the TV off, unplug it, wait for a few hours, unscrew the plastic chassis and slide it off, and then, without touching any internal parts, use my can of compressed air to spray it all over to make the dust whirl all around and leave its resting place on the components inside, and then slide the chassis back and screw it back on?

Is this really such a dangerous operation, or is it exaggerated? Are the warnings only for insane people who keep it plugged in while operating? Or randomly go around poking with their fingers on the internal metallic parts?

I'd rather not die from getting zapped by an old TV, but I also don't want it to catch fire or cease working, and nobody will do professional service on it because they don't even know how these ancient artifacts of a forgotten era work.

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The warning is due to large capacitors that store a charge. Enough to kill if the zap gets you at the right, well wrong, time.

If you don’t stick your fingers in, or have a metal tube on the compressed air thing then you will be fine.

Opened several and been fine, but I also know how to recognize, and discharge, those capacitors using a 5k resistor.

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    $\begingroup$ "5k$\Omega$ resistor" heh. RealMen(TM) use a screwdriver :-) $\endgroup$ Jun 2, 2022 at 14:08
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    $\begingroup$ @CarlWitthoft have screwdrivers with certain marks on them… :) $\endgroup$
    – Solar Mike
    Jun 2, 2022 at 14:51
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I have a wet and dry vacuum. The advantage is that you can plug the hose into either the suction portion or the blowing portion of the air mover.

Old TVs generally don't have fans in them, while desktop computers (laptops) do.

I open up the computer and disconnect the fans (so I don't generate electricity by spinning the fan and forcing this into the computer's mother board) (or in this instance) the TV and blow the dust from the interior and redistribute it to the environment. (Note: don't do this while inside the house.)

Using hosing with plastic parts (that don't conduct electricity) would be safest. This way you don't have to touch any of the electrical components of the TV and the shock risk is lessened (just don't touch any of the electrical components).

Take it easy on long wires connecting various components as wildly moving them with air may damage their attachments.

You might consider wearing a face/breathing mask as many people can be allergic to breathing dust.

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Not very. The picture tube is one of the bigger concerns for holding charge. If I was in a hurry I would take a insulated wire and ground the the terminal on the CRT. Generally voltages had leaked down by the time one removed all screws with an ordinary screwdriver. Keep in mind the CRT sets, generally older than yours, required removing the tubes and taking them to the drugstore test console for testing by the user. Unusually at least once per year. With practice you learn the likely problem such as "horizontal stabilizer". A newer set like yours will have tubes with three functions in a single envelope. Also forgot, color used higher voltages, so more risk. The "flyback" diode also had high voltage. Be careful with air pressure some tubes and other components may not be very firmly anchored.

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  • $\begingroup$ No and no. There is at least one large cap that's used for filtering purposes and can remain charged for years. Not to mention that any CRT TV or monitor manufactured between about 1970 and the end of the line does not have a stack of 12Xkk tubes in the first place. $\endgroup$ Jun 2, 2022 at 14:10
  • $\begingroup$ I guess I am obsolete along with 12 AX 7. $\endgroup$ Jun 2, 2022 at 14:56

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