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High voltage is needed to power the screen. Check the high voltage circuit. Take off the rear panel. The high voltage is need where the 120 volts. There is a high voltage transformer and on the output the volts should equal at least 390 volt DC - check it at the capacitor. If not, check the capacitor. The one in the TV is 100 uf rated at 450 volts. I put in a 370 uf rated at 400 volts.
Shotgunning works sometimes, but the effort spent is often not worth the time spent. Let me explain if your power supply is defective then shotgunning will produce results, however if the problem is elsewhere you will never know it. I would suggest troubleshooting the unit, to determine where the problem really is. For this task I would suggest that you get a schematic diagram of the unit, a multimeter, and an oscilloscope. use the schematic to find the various test points, use the multimeter to measure the voltages at the test points, and then use the oscilloscope to measure the signals at the test points. Troubleshooting in this fashion will produce better results than as with the shotgun method. I would suggest checking for ripple voltage in the DC path. This voltage is due to AC bleed over from poor regulation by malfunctioning filter capacitors. you will not see physical signs of the problem but a quick check of the capacitors will let you know if the is the problem. Also check to see if the DC voltage across the positive terminal of the capacitor is held at the level it should be at. Then check all points on the power supply and compare them to the schmatic.
You did everything that I would have done honestly, with the dvd drive not opening up and the fan not coming on, that would tell me the motherboard isn't regulating the voltage properly since neither is operating.
Either the CPU or the motherboard is bad at this point but I'm leaning toward the motherboard since a bad CPU would not cause a dvd drive not to open but a bad motherboard would especially if its not regulating the voltage properly cause of bad components on the motherboard. See if you can get the motherboard replaced if your machine is under warranty. If not then try to go thru Ebay since places there are less expensive.
This may be a problem in the HV section of your TV. My question is do you have raster, or is the screen totally black? If you have raster then this is a video problem, if the screen is totally black then it is a HV problem. In either case if you do not have a background in electronics I would suggest that you take your TV to a qualified TV technician. If you do have a background you will need the following items:
A schematic diagram of your TV set to know where the test points are and to see what voltages and or signals should be at what point in your TV set A multimeter to measure AC voltages. DC voltages, and Resistance when needed. An Oscilloscope to measure signals that should be present in various sections of the TV as shown by the schematic. A signal generator to create the proper input signal for testing.
These are the major tools needed, not to mention a soldering iron, and a de-soldering tool
This denotes a problem with the power supply either the low voltage power supply of the high voltage power supply. You will need the following documents and equipment if you plan on doing this yourself:
1) a schematic diagram
2) a Multimeter
3) an oscilloscope
4) a signal generator (color bar, cross hatch, and purity)
The schematic will let you know where the test points are and the level of voltage and signal are supposed o be at the test point.
The multimeter will allow you to trace and measure DC and AC voltages throughout the set.
The oscilloscope will allow you to view the waveforms generated by the signal generator, this is needed to tell if a component is not processing the signal in the proper fashion.
The signal generator creates a standard reference to measure by.
Since this prolem is in the power supply section you should determine if the problem is a blown fuse by visually inspecting the fuse. Than you will need to determine if the problem is in the high voltage power supply. You do this by checking the transistors in the horizontal section of the TV. you will find the problem either in the low or high voltage power supplies.
If all you have is a straight horizontal line across the middle of the screen, you have a vertical deflection problem. This may be caused by the opening of the vertical coupling capacitor, an open winding in the yoke transformer, the vertical drive transistor might be malfunctioning, or the vertical output IC chip might be defective. You will have to check all of these, make sure that you have a schematic, a multimeter, and an oscilloscope. Here is why:
1) schematic diagram to know where parts are and the voltages and signals present at test points.
2) multimeter to measure DC voltages on the pins of components
3) oscilloscope to measure signals at test points shown on the schematic.
If you do not have a background in electronics please take your set to a repair shop, however if you have a background in electronics your troubleshooting will be around the vertical section if the tv.