Power tv on and then it clicks and turns off
Most of the time there are one or more 5 amp pico fuses open on the power supply. The cause of them opening is the +/- 30 volt line shorting from the convergence circuit. If you take this repair on yourself and are familiar with a ohm meter, you can check the small green pico fuses in the power supply. Remove the power from the set, take the back off. The board in the center is the power supply and convergence circuit. In the center of the you will a transformer. Just to the left of the transformer you will small green fuses that look like resisters. They are marked on the board but are sometimes hard to see. If one is open for the 30 volt line, the convergence IC's need to be replaced. They are mounted on the back of the large heat sink and the board must be removed to replace them. When you remove the board, be sure to remove all the screws not only around the edges of the board but also in the center too. There are also screws on each end of the heat sink and on the blind side center foot securing a ground wire. On each side of the board there are plug clips that must be lifted. At the front of the board there are plug connectors that need to be unplugged. Once the board is removed the IC's are easy to replace. Remove them from the heat sink, Unsolder them from the board using solderwik. The Convergence IC's should be STK392-570. If there is only one, it is a STK393-110. When replacing them, I recommend using heat sink compound on the back of the IC's where they contact the heat sink. solder in the new IC's then attach the heat sink to them.
Replace the small pico fuse or fuses, they should be rated at 5 amps. Once all the parts are replaced, remount the board making sure the heat sink holes align with the board holes. Reconnect the plug connectors, Plug clips, and reinstall all the board screws.
I hope this helps,
Dec 12, 2010 |
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