47LV5500 powers on but no display or sound

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices.
http://electronicshelponline.blogspot.com/
If blinks continue without any pause, the main board is faulty.
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picture board

Does the screen flash on briefly then go black when first switched on? See my posts in march for my answer to this fault.I traced the same fault on my own tv down to a faulty led in the backlight strip. Also my tv did the same thing,standby light flashed twice and then went out.Hope this helps

hi the tv has detected a fault with the back lighting, now it could be a problem with the voltage to the back light or some of the leds in the back light have failed, it will turn off the back light when it finds a fault. behind the screen there is rows of leds on strips and they all light up when the screen is in use. and the main board knows they are lighting up by the voltage its using. when to many leds go out the voltage is too high so it will turn the back lights off to save them. also the same if the power board is not supplying the right volts. say the volts need to light the back screen is 64 volts and its only giving 62 volts the power is not right so it shuts down. same for if the volts go up to 64.5 volts it will do the same. hope this helps you under stand.

It sounds that the main digital board to this TV is faulty. Contact any service technician.

When the following conditions, you need to replace the LCD screen:
No image on the screen, but the power indicator stays in
Dark display but still readable
Results - 1 of 1 / from by by 2 to a few seconds are of the the the the scintillator of the screen and Close for between the
The power indicator has been lit, but nothing display and sound
No image on the in the screen, but the LCD TV still comes with audio
Pictures cycle open and close the, as well as lamp closed for non high-power LED
http://www.lcdinverter.info/hp-pavilion-dv61247eo-lcd-inverter-p-11136.html

Replace it with a new LCD Inverter, you can address the following issues:
Screen image, but the power light stays in
Dark display, but still readable
Flashing on and off of the screen between 1/2 to several seconds
The power indicator stays on, but no display and sound
Screen images, but LCD TV still has sound
Picture cycle on and off, as well as high-power LED lights
More information in: http://lcdinverter.info

Definitely odd for sound to come through and not sound, especially via an HDMI connection.

I would contact LG for support, your TV could be defective.

Good luck

I had the same problem. all the service reset would only make the display come on for a few second with no "k" on the screen - only the channel would show up. I purchased a complete set of board for the lcd on ebay, and started swapping them one by one. The inverter boards were the culpret. Tele working 100% since that board swap.

Now,u plug in the tv u get a solid red standby power red LED light in the front of the LCD panel right?When u push the power button on the remote u hear a clicking sound?Only one clicking sound,not the power supply board problems.It the Tuner board problems.But u can make sure it the power board problems or not.By taking the tv aparts check the power board,that board where the a/c power cord goes into it.Look all around the power supply board check for these leakage capacitors,they alway bulges up it top or puff up it top.No bad leakage capacitors,then it not the power supply board problems.