Discharging a TV tube

Discussion in 'General Electronics Chat' started by Dave1971, May 30, 2007.

  1. Dave1971

    Thread Starter New Member

    May 17, 2007
    TV is starting going on the blink, suspect dry joints on the power side of the circuit, so can anybody please explain the correct procedure to discharge the tube.
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    Unless your removing the EHT lead from the tube, you shouldn't need too. I'd be more worried about getting a belt from a charged up PSU cap if your diving into the SMPSU.
    I never recommend anyone delve into TV's, VCRs, CD, DVD etc unless they have some sorta knowledge, or are supervised. Not only can it be hazardous, but it can turn what might have been an easy repair for a suitable tech, into an expensive nightmare.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    The method we used to discharge CRT's was to use a clip lead to grab the frame (check to see that it has a connection to circuit ground) and the shaft of a long, thin screwdriver. Using one hand only, slip the blade to the screwdriver under the silicone rubber anode cap and advance it slowly until it touches the metal contact pins. There will be a pop then the voltage jumps to the screwdiiver. Leave it in place for 20 minutes and the CRT will be discharged enough to poke around.

    The CRT does carry enough charge to deliver a potentially lethal shock. Never use two hands while discharging the CRT.

    We abandoned the repair of high voltage circuits because the specific parts weere generally hard to find, and if it was not the driver transistor, there was never a schematic to aid in further troubleshooting. And if the set is new enough to be using lead free solder, a good joint looks pretty bad.
  4. Dave1971

    Thread Starter New Member

    May 17, 2007
    Cheers, thanks for the replys