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LG 55LW5600 problem Symptoms: no audio, no video, no backlight.

Symptoms: no audio, no video, no backlight. Diagnostics performed so far: Power light goes blue/blue white from the standard solid red/orange when powered on with remote control. audible click is heard during the power on cycle, no blink code noted. Flashlight test fails to show anything have disassembled and put light behind the panel as well still no image seen on power up cycle. When powering up after power indicator led has turned blue/blue white TV with back off of unit I press the single black button on the mainboard and i get a momentary flash of the backlights then TV powers down. I i do previous test with allowing tv to power up and stay in blue power indicator status for 1 min or so the button push yields no led backlight flash. Power on TV do or do not not press button on mainboard plug in lan cable to switch or laptop and activity is seen in both cases. Power on and plug hdmi 1 (only port I checked) in to laptop windows recognizes the tv as a second monitor. Voltage through to main board from power supply is 3.46 if i recall correctly on 2 leads into the mainboard from power supply/backlight driver combo board. Voltage out to led cables from powersupply/led backlight driver board is 56+ VDC if i recall correctly on multiple pins / leads. Can I verify with you that this would likely be a failure in what I am seeing referred to as a t-con board?

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The main power supply regulator section circuit fault. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts.
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.

Posted on May 12, 2017

  • Chris Taggart
    Chris Taggart May 20, 2017

    Thank you knight for the response. Can you clarify by main board power circuit are you meaning the main power supply board or the main / mother board? Note my LG has 3 boards 1 power supply with integrated backlight driver 2 main board / mother board 3 tcon board. Another article I read me specified the tcon as the issue on a similar model when backlight flashed momentarily after pressing the single button on the main / mother board. Thank you for your help and note I replaced the tcon because of the other article and the tv still has exact same symptoms

  • Chris Taggart
    Chris Taggart May 20, 2017

    I will add I reviewed the link and the LG diagram which seems to be the power supply board but it's been a while since I've used my Weller station to do board level repair so complete board replace us preferred method of fix.



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Posted on Jan 02, 2017


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Tv problems lg and vizeo

Power Issues Troubleshooting
*NOTE* LG & Vizio TVs must be plugged in for 5 minutes before it will turn on*
1. Inspect ALL Ribbons and connectors. Any tears or bad connections between boards must be replaced FIRST
2. If you have any of these boards, it should be the first board to be replaced
A) T-Con Board - Video Problems (No Video with standby light on, audio but no video, grainy, distorted, or color problems in screen)
B) X or Y Buffer Board (Plasma TVs only) - Standby light is on but no power
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3. Main Video Board
- Standby light is on but no power
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Try a "REBOOT"

Reset, Initialization &
Option Menu
Front Panel Reset & Initialization
Many customer generated symptoms, intermittent symptoms
or symptoms that cannot be duplicated can be resolved
by performing resets or initialization from the front
panel. To avoid making nuisance service calls that may
not be covered under the warranty, ask the customer to
perform the following functions before going to their
The most common are:
• System Reset (Re-boot)
• A/V Reset (Resets Customer Audio/Video
• Initialization (Resets all customer options,
settings and menu items)
Use the Front Panel Guide as a reference to quickly
perform the desired function. Note: Button location may
differ by model.
The Reset - Initialization Guide details all resets and initialization
Front Panel Guide
1) SYSTEM RESET1 - Reboots Set
(Same as Cycling AC Power)
Power LED will flash for about
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Resets all Customer Menu and
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In case of failure, a 2 digit error code will
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1 Perform while the set is either On or Off. (See section on LED Diagnostics)
2 Perform while the set is On.
3 Perform while the set is Off.

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if you look at the Power Supply Board you will see the one been damage it cost about 0,50 pence only

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