Hi...please help me. My samsung 21" tv got no picture and sound at all, even standby LED also not light on...I already do some troubleshooting and found that power supply for the biggest capasitor got 350v...also at horizontal transistor B+ got 158v (is that too big supply for horizontal B+..?).... and another thing got a strange sound came out from flyback transformer..it sounds like "tick..tick..tick.....frequently" .....then, i check where the 158v came from and found it was came from 1 diode that link to horizontal B+....before diode got about 100v and after diode got 158v that link direcyly to horizontal B+. So, what in the world happened to my tv? what should i check and do?
This is like a car running without a driver,the horizonatl output transistor has the voltage it needs but it does not have horizontal drive signal applied to the base of the horizonatl driver transistor,the driver transistor should have a signal coming from the signal processor where the signal is generated just to get give it to the driver this driver then it gives it to the output to energize the flyback and light up the picture tube and generate a few other supplies,158 volts are there because the output is not turn on,try measuring voltage somewere else in the set and not at the collector of the output,there is a b+supply that goes to the signal processor(8 to 12 volts),check to see if you have this voltage,I couldn't tell you the pins in the siganl processor IC without squematic,It seems you know your way around tv service but be careful when checking voltages.Let Us know if you need more information.
Posted on Oct 10, 2006
Anothe thing....The power supply generates the voltage for the signal processor but the 5 volt supply for the micro(brain)branches off of that supply.If you are missing the 5 volats the brain will be dead too.
If the 8 volts is missing it will be better since you can back track to were is generated and see were you loose it,it has to be there to start the horizontal oscilator,this one exits the processor to be base of the horizontal driver the dc volts at the collector of the driver should be only about 60 volts.
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I hope you have the service manual for the unit.
You need to check the collector voltage of the horizontal driver transistor.It should be only about 60 volts.let me know.
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i already check there's +5v at remote control receiver LED on board..do you mean that my system (processor) ic got problem or other component? so, what if i got 8v at pin processor and what if i dont...?? please help me..!!
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