will i get an elecric shock????

Discussion in 'Macintosh Computers' started by Souljas, Jun 20, 2004.

  1. Souljas macrumors regular

    Feb 4, 2004

    im soon going to be taking apart my old Performer 5320, however I was a bit worried that I would get a shock from the stored charge in the CTR. Can anyone tell me how to dicharge this charge, or how long i have to leave it for unpugged, or anything else I can do.

    thanks, Soul
  2. rainman::|:| macrumors 603


    Feb 2, 2002
    Well you're correct in that the capacitor on a CRT (cathode-ray tube) can hold a lethal charge, even after being unplugged. This can make for tricky work on one-piece computers. I've personally owned a Mac Plus, SE, and two iMacs, all of which have integrated displays... whenever I've worked on one of these (or a client's computer) i just avoided touching the CRT. If there's a proper way to discharge it, I don't know it. But as long as you don't touch it, you'll be fine. Hopefully someone else can give a more proper assessment.

  3. ephramz macrumors member

    Jan 14, 2004
    Screwdriver lifesaver

    Capacitors and other parts of the monitor too I believe can hold around 10,000 V even a long time after being unplugged. You can discharge a capacitor by holding a screwdriver with a plastic handle across the two leads. Hold one end on one contact and then tilt the other end of the screwdriver towards the other lead on the capacitor till you see a spark. If there is no charge it may not spark.

    Other good ideas for working near high voltage stuff:
    - always work with one hand behind your back. This way if you get a shock it won't go through one hand, across your heart, and down the other hand and possibly kill you. If only one hand touches something high voltage, you will just get a jolt in that hand, but it won't run through your vital organs!
    - also I believe the connectors at the end of the CRT can be quite fragile, so try to avoid bumping them at all costs.

    Good luck.
  4. KingSleaze macrumors 6502

    Feb 24, 2004
    So. Cal
    A method drawing less of a current (and consequently, no spark) is to use about a 10,000 ohm resistor. Hold it with insulated needle nose pliers, and touch both leads on resistor to both leads on the capacitor at the same time. This could be difficult to accomplish.

    Alternately, take your voltmeter (on a high scale, DC) and measure the voltage across the capacitor. You can watch as the stored charge is disipated.
  5. Souljas thread starter macrumors regular

    Feb 4, 2004
    thanks guys, i might have to post up a few pictures ( if im still alive :eek: ) of the crt so you guys can help me using pictures, ( if you dont mind)


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