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the first thing you can do is to unplug the tv unit not to used for an hour to discharge excessive voltage at the power supply board to reset the dc supply at the main board. then after an hour try to plug and turn it on. if still doesn't work at this time you will need to make a voltage checking if you know a basic electronics trouble shooting or you want a DIY just follow some of my steps by steps repair instructions.first you must need to check the output dc voltage at the power supply section, if their is an output which supply the whole circuit just be careful since you are dealing with some high voltage. the supply at the indicator light at the front is just only the stand by voltage. you will need to check the B+ voltage which around 110vdc at the horizontal section which turn on the whole circuit. you can used a digital tester to make a voltage checking just set to dc voltage. if their is no presence of 110v dc at the horizontal the vertical and the tuner section will not turn on. usually the cause problem like this is bad horizontal output transistor and an open resistance circuit going to transistor.check also for an open or defective resistor replaced it with same value.hope this can be helped just let me know if it works feel free to ask further solution thanks for using the fixya service good luck.
Replace its Horizontal output Transistor. If the base-emitter junction has a leak inside it, this type of fault will occur. Before replacing it, check the main DC voltage to LOT [Line Output Transformer]. It should come around 102VDC. If there is not this much voltage, check the electrolytic filter capacitor connected across thie supply line to main negative for open or value developed. Replace the same is good. Till there is low voltage found, check the retifier diode that rectifies this 102 volt DC. If all the above are OK and still you get a stamp like raster, check the heat of the Horizontal Output Transistor described above. if it overheats, LOT is defective and should be replaced with same type and number. OK.
As sound output is ok, main board is correct with respect to sound output, video IF and ther stages. The fault lies on the horizontal output section. It may be LOT fault. Check it further for horizontal oscillator stage, and horizontal output stage. Check the collector voltage at the horizontal driver transistor. If you have a frequency meter, check the frequency of that point. It should be somewhere near 15625Hz. If the frequency there is Ok, then proceed to horizontal output stage. Check the horizontal output transistor. If it seems to be faulty, replace it with similar type and number. If the replaced horizontal output transistor heats abnormally within seconds after swich on the set, surely LOT has troubel. Replace it also with same model mumber and type.
first check dc voltages of smps output,that is 110v,18v,12v and5v,.If it is all right then check horizontal output transistor collector voltage(180dc) and basc voltages (1.5dc).if it is all correct ,then check osc .if it is also correct please check LOT AND vertical ic . brepklace ment methode.
Flyback is a step-up transformer multifly the voltage depends on the size of the tube and supplied high voltage to cathode ray tube.The minimum output voltage of this is 14000v DC for 14 inches crt monitor what if your crt is 17 inches 17000v DC very dangerous if you are not electronics repairman.
The horizontal output transitor is always connected to the primary winding of the flyback transformer (via collector) and also to the horizontal deflection coil via an electrolytic capacitor.
The most likely suspect for damaging the transistor is the fylback transformer. In some countries there are electronic stores that test flyback transformer by winding a few turns on the ferrite core and applying a test voltage. This test will only test the secondary.
The primary winding is difficult to test for turn to turn short because the resistance is quite low and you do not know the 'good' resistance.