Originally Posted by JimmyCC
No, my LED driver board is certainly kaput again. What I am talking about is performing any measurements on the individual LEDs themselves out of circuit. Here is what I have done:
1) Placed 9-volt battery with volt meter and current meter on each LED.
a. Blue LED lights up 6 Volts on voltage meter ~ 1.0 Amp on current meter.
b. Green LED lights up 5.6 Volts on voltage meter ~ 1.1 Amp on current meter.
c. Red LED lights up 4.3 Volts on voltage meter ~ 1.5 Amp on current meter.
I am guessing with the current draw my 9-volt was loosing juice quickly and thus the lower voltage with measuring the next LED.
2) Resistance measurement on each LED. Notice the difference from K Ohms to Ohms between blue and green / red.
a) Blue LED > Pos probe on white Neg on blue = 21.8K Ohms. Leads reversed > 20.4K Ohms.
b) Green LED > Pos probe on white Neg on green = 41.8 Ohms. Leads reversed > 42.0 Ohms.
c) Red LED > Pos probe on white Neg on red = 29.7 Ohms. Leads reversed > 29.8 Ohms.
3) Diode check using Fluke DVM.
a) Blue LED > Pos probe on white Neg on blue = 1.93 Leads reversed > 1.65.
b) Green LED > Pos probe on white Neg on green = 0.028 Leads reversed > 0.028.
c) Red LED > Pos probe on white Neg on red = 0.020 Leads reversed > 0.020.
What I am trying to determine is if it is possible that any of the LEDs could be failing and due to their failure be damaging the LED driver board. As stated in my earlier post I replaced the LED drive board and everything was back to normal...for about 7 days. Then the new board failed with the exact same symptoms as the original. I am to receive a replacement LED driver board from Andrews this week. I would like to be comfortable that no other component is causing its failure. Since all three LEDs light up fine I find it hard to believe they could be the cause. But I have never had one of the LEDs go bad so I don't know their characteristics. I have seen where others have installed extra fans. Would anyone suggest that I do this as a precautionary measure? I like this TV and would like to have it operational again for a long, long time.