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Anonymous Posted on Mar 09, 2022

Sled4248 power supply cuold be bad?

I have a Sansui SLED4280 T.V. My problem is the leds drop out. When this first happen I replace the led driver board. When I turn on the T.V everything seem to be working fine for about a hour then the leds drop out. I turn off the T.V for 10 minutes after that I turn back on. The leds work for about 5 minutes I turn off for 2 minutes leds work for about 20 seconds. Could this be a power supply problem? Thanks

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Larry

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  • Sansui Master 5,042 Answers
  • Posted on Mar 10, 2022
Larry
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This set is a bit more complex to repair backlight issues as it has local dimming, that's why it has the extra LED driver board. Start by testing the BL_ON pin to see if signal is coming from the main to keep the backlights powered, you should be around 3 vdc there, hook a multimeter to that pin and leave it on tell the lamps shut off, if the voltage there drops you have main board issues, if it stays then the main should be ok, the power supply on this set feeds the backlight inverter (driver) board. Next test is check the backlight inverter voltage to frame ground if the main tests ok, if that's ok and the driver has been replaced you have defective backlights and I think this will be the issue however it's way to much work to pull the panel out to get at the lamps and find they're good so do the other tests first to know where your issue is at verses just guessing what the issue is. Hope this helps and good luck!

David Spradling

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  • Sansui Master 13,524 Answers
  • Posted on Mar 10, 2022
David Spradling
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See if voltage drops when it goes out if so bad power board

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