Actually horizontal lines base on my own experience will cause of bad/faulty T-con board and the low screen light (back-light) cause of bad inverter board or weak cold cathode light when the 2 parts are both indicate faulty (inverter and T-con) the possible problems is on the power supply board..Because its very rare to LCD having 2 or more boards fault..
If that is the case..You need to check the power supply board (it is usually connected directly to the power cord)..Power supply is very hard working parts of all LCD TV so that this board is a commonly problem of all flat panel TV..This board is the one that responsible to supply DC voltage such as 5vdc,12vdc,24vdc to all the boards to function it properly..If the power supply board having voltage drop on there output all parts are not properly works until time comes that the TV will not turn at all..
Try to inspect the power supply first..Look at the power supply board (usually connected next directly to power cord).
Try this numerical steps.
- Open the back cover.
- Locate the power supply board.(usually connected next directly to power cord).
- Inspect the power supply board for any bulged/dome capacitors.
4. If you found any bulged capacitors like the picture above kindly replace it with the same value (example:1000uf/35v means 1000microfarad/35volts)..
5. When you replacing the capacitors make it sure that you memorized the exact position of it because capacitors having polarity.Wrong polarity can cause more damaged.To make it sure please take a picture of it to avoid mistakes..
6. After replacing bad caps if any..Try to power it on again..
Hope it helps..If not please let me know..
Just keep on touch to me to fix your TV..