Saturday, November 03, 2012

HOW TO DISCHARGE THE FINAL ANODE OF A PICTURE TUBE.


     If you are working on a CRT type projection TV set, you have three picture tubes that should be discharged to prevent accidental shock. You can discharge the picture tube’s anode at any of the R, G, or B outputs on the High Voltage distribution block only by:

     First connecting one end of an insulated clip lead to the ground on the back of the picture tube, or the mounting plate of the picture tube. Then touch the other end of the insulated clip lead to the wire coming out of the High voltage distribution block, or by using a long handled screwdriver, with the clip lead attached and slid up underneath the rubber boot on the picture tube High Voltage connection.

     All TV sets that have a picture tube will have a high voltage transformer with a heavy red wire that runs up and connects to the picture tube with a suction cup. Under there is an average of 32,000 volts when the sets on.

      Even when the set is off, it can hold a large electrical charge. If it zaps or bites you, it can make a grown man cry, and not only that, can stop your heart! Therefore, the point is to never ever stick a screwdriver under the High Voltage cap even if it is unplugged.

     If the cap has to be removed, attach one end of a clip lead to the metal exposed strap that is around the picture tube, and the other end to the screwdriver. Without the metal blade of the screwdriver being exposed to you, slide the screwdriver under the cap slowly. There should be a little pop if there is any voltage left. Wait for a second or two, remove the screwdriver, and pinch the top of the cap perpendicular to the wire while pulling up on it. Never pull on the wire. With the cap off, clip the clip lead to the anode connection on the tube while the other end stays on the grounding strap. You can watch a youtube video here on how this is done.


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