The TV starts ok, but then the screen goes blank, sound stays on and soon after the TV shuts down. The power light turns red and flashes once every 1.5 seconds. This indicates either an inverter or backlight fault. While the power light is flashing red, press the menu button on the remote (pointing it at the TV obviously!). If the OPC light does not come on then it indicates an inverter fault, however if the OPC light starts flashing at the same rate as the power light this indicates that it is a backlight fault and this fix may help you.
The complete LCD screen assembly needs to be taken apart for this fix which is a delicate job and if you are not careful you can severely damage the screen making the TV useless so be careful!! Also the inverter board that powers the CCFL (Cold Cathode Floresent Light) tubes puts out around 1500 volts so NEVER touch the inverter board when the TV is powered up unless you know what you are doing.
The backlight tubes can be replaced if needed, but its usually a fault with the backlight connectors that causes one or a few tubes not to light. If you own a CCFL tester that can test 1000mm tubes you can test the tubes without taking the screen assembly apart. Remove the inverter board, connect one side of your tester to the metal chassis, and then probe each of the 18 backlight connectors. You will probably find that all 18 tubes will light and test ok.
If all 18 tubes test ok, or you are unable to test them, you will need to take the screen apart to be able to take out the connectors to inspect/repair them.
The service manual can be found by searching for it in any search engine this will tell you how to take the screen assembly apart (i hope to add this data to the site sometime soon)
Once the screen assembly is taken apart you will see a plastic lens sheet on top of a diffusion plate. Take care at this point as you remove the sheets to notice on one corner of each sheet there will be a notch or the corner will be cut a little. Also note that one side of each sheet will be slightly rougher than the other side. Make a note of where the notch is and which direction the rough side is facing as if you put them back in wrong, you will have very bad picture quality as I found to my cost when I fitted them incorrectly at first.
When you have removed the lens sheet and diffusion plate you will see the backlight array with a plastic cover clipped on at each end. Gently ease each cover off.
At the opposite end to the inverter connectors you can do a continuity test with a standard multimeter. Test between the metal chassis and each backlight, they will all probably test ok. So you have to move onto the invertor connectors. To remove each of the 18 connectors, very carefully pull the end of the tube straight upwards, just enough to clear, then gently push it to the side of the connector and pop the connector out by pressing from the invertor side towards the backlight side. Always handle the backlight tubes very carefully when moving one end of it around as you dont wanna break it and give yourself more expense.
When you have all the backlight connectors removed you can inspect all of them. You will probably notice that one or more have corrosion or blackness where the inverter board plugs onto it. It is advisible to pull the metal out from the plastic, by gripping one side of the backlight clip with a pair of tweesers or small pliers, and taking some fine sand paper or emery paper and clean off the corrosion, next re-bend the metal slightly so that the two bits that connect to the invertor board are almost touching each other and it looks square (I hope to be able to upload pics of this sometime soon) and then slide the metal back into the plastic.
Look into the clip where the invertor plugs in and make sure that the top of the metal bit is completely up inside the plastic, if it is not, use a small screwdriver to push it up into place. This is important because if the metal is showing at the top, plugging in the inverter will bend it giving you more problems. The only metal you should see from that side is the 2 clips that connect to the invertor. It is time consuming, but advisable to take all 18 connectors apart and re-bend all of them to make sure they all grip the invertor tightly.
Next, look at the inverter board and each of the 18 connections, there may be blackness on some of them. Use switch cleaner spray or very fine sandpaper to clean them all up. Any that are looking in bad shape after cleaning will require you to coat them in a thin layer of solder.
When this is all done, put it all back together and hopefully you will now have a fully working TV! Good luck!