Hi there,
Samsung tv, like new condition ( Aug 2019), plugged-in, power up (without pressing the power button) with backlight on but no start up sound, no image. Cannot be power off by the switch or remote. Removed screw-less back cover and inspected the power supply and main board…no suspected components… disconnected one or both LCD ribbon cables, same status. Voltages 13V and 3.3V are OK.
However, when is plug-in, the main board has a chirping sound for 3 to 5 sec before backlight is starting. At this point I want to confirm that it is a hardware or software issue. For a better access, removed the processor (huge) heatsink and checking for short to ground of capacitors and coils. The microprocessor is powered by TPS56C20 (12-A synchronous buck converter) and the output coil L324 show low resistance measured to ground 2.8 ohm. The coil output voltage is 0.80V stable. On the back site of board (same location) there is a capacitor C336 showing same resistance. Is that normal ?...
Samsung tv, like new condition ( Aug 2019), plugged-in, power up (without pressing the power button) with backlight on but no start up sound, no image. Cannot be power off by the switch or remote. Removed screw-less back cover and inspected the power supply and main board…no suspected components… disconnected one or both LCD ribbon cables, same status. Voltages 13V and 3.3V are OK.
However, when is plug-in, the main board has a chirping sound for 3 to 5 sec before backlight is starting. At this point I want to confirm that it is a hardware or software issue. For a better access, removed the processor (huge) heatsink and checking for short to ground of capacitors and coils. The microprocessor is powered by TPS56C20 (12-A synchronous buck converter) and the output coil L324 show low resistance measured to ground 2.8 ohm. The coil output voltage is 0.80V stable. On the back site of board (same location) there is a capacitor C336 showing same resistance. Is that normal ?...
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