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I have a CRT monitor which I was looking to open to acquire CRT for a project I am working on. I know its probably not the best idea but I have taken some safety measures. They are as follows:

1) Switched off and unplugged the monitor and made it sit for 3 months.

2) Read about high voltage circuits and the dangers they pose.

3) Ordered a good pair of Rubber Gloves

4) Watched some videos on Dismantling.

I wanted to know is 3 months enough time and How can I make sure if I have discharged everything that needs to be discharged? Is there any specific components which is considered dangerous?

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  • \$\begingroup\$ After 3 months the high voltages will have leaked away for sure. As an extra measure you could also deliberately discharge the high voltage by using (isolated) pliers and taking out the plug that is on top or side of the CRT tube, see that RED thing in this picture: pc-schoonmaken.nl/images/content/crt-monitor/open%20crt.jpg and connect the metal pin inside to the metal chassis of the monitor. Then for sure there will be no high voltage left. Using a screwdriver you could also short the pins of large capacitors to discharge them. Most dangerous is the CRT if dropped on your toes:-) \$\endgroup\$ May 23, 2016 at 19:36
  • \$\begingroup\$ The procedure I used, recommended by the manufacturers, was to leave the red plug attached, and slide a tool underneath the red insulator and probe around to find the clip/plug. Safety first: Other hand in your pocket, no grounding strap, touch or lean on nothing. The tool has a jumper lead, which you clip to a steel bolt at a corner of the CRT. This can be an insulated screwdriver and an alligator clip test lead (when you hit it, you'll know it)... or a proper CRT discharge tool, which is that plus a megaohm resistor. (makes a quiet "hiss"). \$\endgroup\$ May 23, 2016 at 20:37
  • \$\begingroup\$ @Harper Why do you add that as a comment, after answering? This looks to me like a thing to add to your answer rather than add as a comment. \$\endgroup\$
    – Asmyldof
    May 23, 2016 at 20:39
  • \$\begingroup\$ I just did, partially. For liability reasons I don't feel comfortable reciting the discharge procedure as an answer. It's readily available online. \$\endgroup\$ May 23, 2016 at 20:43

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Three months is not long enough. I used to service several brands of CRT monitor. I did the discharge procedure even on CRTs known to have been stored for months. Indeed, quite a few still had a charge.

Just do the discharge procedure. It's not that hard... and it's fun.

Safety first. You are dealing with several thousand volts with enough current to potentially kill (or knock you out, which can cause secondary injuries). Make sure it has no possible path through your body. You should have nothing tying you to ground (no grounding strap), don't lean on anything or touch anything, one hand in your pocket. Don't be tempted to grab the CRT to steady it, that's how you get shocked.

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  • \$\begingroup\$ I have another question tho, I was thinking of constructing a discharge screwdriver tool. I was thinking of soldering a 12 gauge insulated wire and 1 Mega Ohm resistor to the screwdriver. Should I make and use this tool or simply the screw driver and wire will work? \$\endgroup\$ May 24, 2016 at 8:20
  • \$\begingroup\$ I think most people would view the megaohm resistor method as safer. The advantage of the no-resistor method is you certainly know when it has discharged! \$\endgroup\$ May 24, 2016 at 8:22
  • \$\begingroup\$ That is what I was thinking, Both have a pro and con. Isnt there a way maybe use a DMM to measure the current coming out of the resistor to ensure that it has discharged. Can I do something like that to be on the safe side since I would know that it is discharged when current stops travelling \$\endgroup\$ May 24, 2016 at 8:24
  • \$\begingroup\$ Darn right, definitely discharge the CRT.. I did that once, I forgot about the 1 Megohm resistor and woke up across the room. 26Kv will do that to you.....Don't remember going from point A to Point B...Woke up at Point B \$\endgroup\$
    – Old_Fossil
    Apr 11, 2018 at 6:52

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