I stated testing this unit and I had no backlights but I can see a picture with a flashlight to the screen. I started testing voltages at the 10 pin connector on the Power supply board (BN44-00774a) where the main board harness plugs in but and I accidentally touch 2 pins together (I believe it was pins 7 (13volts) and pin 9 (ground) Now I have no picture and no led on t con board. The red standby light come on and I can see the optical red light also illuminate. The backlights were shorted and was my original problem but now I cause this problem.
Voltage is as follows on these pins:
(1) 12.8v (13v)
(2) 2.33v (od/us
(3) 12.8v (13v)
(4) 3.29v (blu/pwm)
(5) 12.8v (13v)
(6) 4.49v (ps/on)
(7) 12.8v (13v)
(8) ground
(9) ground
(10) ground
Voltage @ cm863
11.9v (standby) voltage drops to 10 or so volts when main board plugged in (load)
12.8v (on) voltage tropes to 11 or so volts (load)
Voltage @ cnl 802 (output to backlights)
320v to 280v with main board unplugged
280v and drops with main board plugged in
Ps/on voltage drops from 4.49v to under 1v with power on and 4.49v in standby
The backlights were unplugged during these voltage readings because I know I have to repair them due to being shorted.
My question is does it sound like the main board was damaged when the pins were shorted during testing or maybe the Power supply got damaged? Before I go throwing parts at this tv I would like to see if there is anymore testing that can be done to be sure. I am not a tv repair guy but I do have electrical background in other areas. Please excuse me if I am not asking the correct questions or not testing what I should be. Any help to push me in the right direction would be greatly appreciated. Thanks.
Voltage is as follows on these pins:
(1) 12.8v (13v)
(2) 2.33v (od/us
(3) 12.8v (13v)
(4) 3.29v (blu/pwm)
(5) 12.8v (13v)
(6) 4.49v (ps/on)
(7) 12.8v (13v)
(8) ground
(9) ground
(10) ground
Voltage @ cm863
11.9v (standby) voltage drops to 10 or so volts when main board plugged in (load)
12.8v (on) voltage tropes to 11 or so volts (load)
Voltage @ cnl 802 (output to backlights)
320v to 280v with main board unplugged
280v and drops with main board plugged in
Ps/on voltage drops from 4.49v to under 1v with power on and 4.49v in standby
The backlights were unplugged during these voltage readings because I know I have to repair them due to being shorted.
My question is does it sound like the main board was damaged when the pins were shorted during testing or maybe the Power supply got damaged? Before I go throwing parts at this tv I would like to see if there is anymore testing that can be done to be sure. I am not a tv repair guy but I do have electrical background in other areas. Please excuse me if I am not asking the correct questions or not testing what I should be. Any help to push me in the right direction would be greatly appreciated. Thanks.
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