I have an HP LC3760n which uses sharp power supply LC504-4201cc. The power indicator flashes green. I replaced the power supply, same issue. I tried the procedure of remove power cord, hold power button 10 seconds, plug power cord, no change. Next procedure - remove power cord, hold vol + chan - at the same time while plugging power cord. Now TV powers on and shows channel in upper right screen, but no 'K' in middle of screen and pressing the remote chan + has no effect on displaying or clearing error codes. I now have volume, but no picture, and able to change channels & volume, and remote is active.

On sharp LCDs, that indicates some sort of power issue, or power supply issue

That sounds like the safety shut down for the power supply board kicking in.

You could shotgun repair it by replacing the board but without a manual it's a bit like shooting in the dark and I can't find the repair manual out there, but here's and idea of the component modular board costs.

http://www.shopjimmy.com/hp

Hello,
Power supply board just die.It can be dead at anytimes.Tries websites Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.

Do take care.....

Change the power supply board - LC504-4201CC 161WJQZ is the power supply board for the LC3760N TV

The power indicator light on the back of the Power Supply flashing when power cable plugged in, indicates a problem with the power supply. There is a short somewhere in the wiring. It will need to be replaced.

The Green LED light flashing indicates a bad Power Supply. Weak voltage power rail.

http://h10025.www1.hp.com/ewfrf/wc/product?product=404643&lc=en&cc=us&dlc=en&submit.y=7&submit.x=7&lang=en&cc=us

Troubleshooting Power Supply Issues HP Pavilion A520n,

http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph06788&tmp_task=solveCategory&lc=en&dlc=en&cc=us&site=null&lang=en&key=null&product=404643#N207

Click on > Power Supply light is on or flashes

"If the LED is still flashing (it should not flash with all connectors removed), plug the power cable into a different power outlet that is known to be good. If the LED still flashes, the power supply should be replaced."


Cause?
The leading cause is the computer is dirty inside, to include the Power Supply
The next cause is that Electrolytic Capacitors have failed inside the Power Supply.

Solution is to replace the Power Supply.

The Power Supply used is the ATX form factor. The type of Power Supply used in over 80 percent of PC computers out there, and very readily available.

Size of the power supply case is approximately 6 inches Wide, 5-1/2 inches long (5.5), and 3-1/2 inches Tall. (3.5)

It is a 250, or 300 Watt generic unit, probably made by Bestec, Delta, or HiPro.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00072236&tmp_task=prodinfoCategory&lc=en&dlc=en&cc=us&lang=en&product=404643

Scroll down to see the illustration and photo of the motherboard.

Power cables needed are;

A) 20-pin ATX main power cable,

http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain20

{ ATX power supply's today come with a 20 + 4-pin ATX main power cable.
The power cable can be used as a 20-pin, or a 24-pin.

Add the 4-pin connector to make it a 24-pin, or do not use it, and have a 20-pin }


B) Enough standard 4-pin Peripheral power cables for the IDE (PATA) harddive, {1}, and the optical drive/s.

http://www.playtool.com/pages/psuconnectors/connectors.html#peripheral

Today's power supply's come with either at least 4, or 6 of these power cables.

C) One Floppy Drive power cable.
Won't be used for a Floppy Disk Drive on your computer. It's power for the Memory Card Reader.

http://www.playtool.com/pages/psuconnectors/connectors.html#floppy


All of the above power cables are typical when purchasing an ATX power supply today.
Need guidance in choosing a Power Supply, please state in a Comment.

Regards,
joecoolvette

Try these suggestions:

<a href="http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph06788&cc=us&lc=en&dlc=en&product=427167&dlc=en&lang=en#bph06788_section_2" >Troubleshooting Power Supply Issues</a>

Replace the whole board,LCD usally the IC is dead,not like DLP the capacitors,burn most of the time.

I had the Same issue. on a 50PF9431D/37 set. Many Plasma Set's use a LJ44-00118A PS-505-PH Power supply from Samsung. Known to have this common problem. If you can, or have a friend that can Solder components?. Unplug your set remove the back panel & locate your power supply. It will be the PCB in the center of the set just above the Video/Audio connections. http://www.shopjimmy.com/power-supply-unit-lj44-00118a-from-philips-50mf231d-40.htm. Is a Link to a photo of the PCB. Make a note of the locations of all cable connections then unplug them all. Un-install PCB, Check all Fuse first. I believe their is 5 or 6 of them on the PCB. Then replace the two 3300uf 10v 105C Radial capacitors at C8060 & C8059. Look to see if the Caps are deformed and or split at the top. The location of the caps are in the Lower bottom edge of the PCB. A local shop may Carrie them if not, digi-key has them. Part # http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=493-1754-ND. Total cost was $7 with S/H.

Have you tried removing all cable connections on it and turning printer off and unplugging it from power supply and powercycle?