Picture and Sound, No backlight RCA 46" LED46C45RQ
crwdns2934249:0crwdne2934249:0:
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My TV has sound and picture, but no backlight. Replaced powerboard but no change, still no backlight. Tested LEDs with backlight tester, they all work. Reading on backlight tester is 107 for both sets of LED wires. All LEDs light up when tester is applied. Backlight control connector tested with multimeter, three leads, GND, ADJ, BL-ON. When TV is turned on, ADJ starts with 4.78 volts and after a few seconds drops to 2.63 volts. Sometimes LEDs will flash as voltage changes from 4.78 to 2.63. BL-ON stays around 4.77 volts when TV is on. On original power board, I removed the two NPN transistors that drive the LEDs and tested them with HFE on multimeter. Both passed test with around 140 HFE. Data sheet says HFE should be above 100. I damaged the board solder pad so had to get another power board.
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All power leads coming from power board have near correct voltage, within .25 volts.
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[image|2384687]
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[image|2384689]
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[image|2384688]
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[image|2384690]
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[image|2384702]
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Disregard, i’ll try to find someone that can help me.
Picture and Sound, No backlight RCA 46" LED46C45RQ
crwdns2934249:0crwdne2934249:0:
My TV has sound and picture, but no backlight. Replaced powerboard but no change, still no backlight. Tested LEDs with backlight tester, they all work. Reading on backlight tester is 107 for both sets of LED wires. All LEDs light up when tester is applied. Backlight control connector tested with multimeter, three leads, GND, ADJ, BL-ON. When TV is turned on, ADJ starts with 4.78 volts and after a few seconds drops to 2.63 volts. Sometimes LEDs will flash as voltage changes from 4.78 to 2.63. BL-ON stays around 4.77 volts when TV is on. On original power board, I removed the two NPN transistors that drive the LEDs and tested them with HFE on multimeter. Both passed test with around 140 HFE. Data sheet says HFE should be above 100. I damaged the board solder pad so had to get another power board.
All power leads coming from power board have near correct voltage, within .25 volts.
[image|2384687]
[image|2384689]
[image|2384688]
[image|2384690]
[image|2384702]
My TV has sound and picture, but no backlight. Replaced powerboard but no change, still no backlight. Tested LEDs with backlight tester, they all work. Reading on backlight tester is 107 for both sets of LED wires. All LEDs light up when tester is applied. Backlight control connector tested with multimeter, three leads, GND, ADJ, BL-ON. When TV is turned on, ADJ starts with 4.78 volts and after a few seconds drops to 2.63 volts. Sometimes LEDs will flash as voltage changes from 4.78 to 2.63. BL-ON stays around 4.77 volts when TV is on. On original power board, I removed the two NPN transistors that drive the LEDs and tested them with HFE on multimeter. Both passed test with around 140 HFE. Data sheet says HFE should be above 100. I damaged the board solder pad so had to get another power board.
All power leads coming from power board have near correct voltage, within .25 volts.
[image|2384687]
[image|2384689]
[image|2384688]
[image|2384690]
[image|2384702]