Hi I hope that someone can guide me in the right direction to solve this fault. I have an LG RZ-20LA70 TV wich will only intermitently turn on. when in standby if you press the power switch the led always changes from red to green. Sometimes it will power up ok but normally all that can be seen is a white screen (backlights of the lcd turn on) but no video, audio or on screen menus. under fault conditions a soft pulsing sound can be heard from the speakers. I would appreciate any feedback regarding this. Thanks
It sounds like the power is pulsing - that would explain your speakers. Speakers wouldn't make that sound if they were getting power at a steady rate. Look for a bad capacitor. It's possible you have one or more capacitors that have gone bad. They charge to a certain point, then somehow complete a circut momentarily and discharge, giving a pulsing flow of electricity. You can look for visible signs (leaking capacitors, or capacitors that are leaning over), or you can just start testing them with a voltmeter. If you find a bad one, you'll have to get a replacement and solder it in place.
Hi, this description usually indicates power supply failure, you can verify this by checking the output voltage of power supply. Cause of the error can be electrolyte capacitors. You can identify them by swelling at the top of the condenser. If you have the technical ability? so there are a few more options for testing. In any case always possible to replace all power supply. Good luck! Let me know if everything worked out, or if you need further guidanc
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