Samsung BN44-00775A no Power No STB or Power lights.Help needed

[TKF]

After a lot or reading and searching I suspected PB Power Board#BN44-00775A but after voltage tests I'm not sure what they indicate or point to.
1st I unplugged MB and left only BLs plugged in to see if I got light No BLs come on. So I suspected Black lights but then tested BLs with BL tester they came on. I suspect a short somewhere I started testing at the STB pin 8v/on13v I get 12.80v note no stb lights on
I noticed with only MB plugged in MB showed signs on life saw red light on not sure from where and it started warming up.
Thanks for any help or ideas or testing suggestions to follow

[TKF]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

Updating my 1st post I was unable to edit it got timed out

Samsung TV Model- UN60H6203AFXZA. No STB or Power lights
Power Board - L60H1 EHS BN44-00775A - Main Board- BN97-08810A 0013

Things I've tried so far, I took voltages with everything connected I got only 1.5v at STB/On pin,
I disconnected all connections except Power Board and got voltages,
Then checked voltages with different combinations of boards connected and disconnected.
IdentifyBox CNM803-pins 1,3,5,7,-A13V,9-Gnd
pins2,UD-4,PWM-BLU-6,PS-ON 8,10,GND Voltages Readings below

-Power Board only connected
pins 1,3,5,7,12.82v,9-0
2,UD-2.30v
4,PWM-BLU-3.30
6, PS-ON-3.90
9,-gnd

-Power Board &Main Board -
pins 1,3,5,7,-2.76v, 9-0
2,UD- 3.30v
4,PWM-BLU -0.75v
6,PS-ON -3.33 Pins
8 &10 gnd
When PB & MB when 1st plugged in, STB light flashed 6 times & Main Board showed signs of life and started to warm

-With Only Back light & Power Board
pins 1,3,5,7,-1.63v, 9-0
2,UD, 0
4,PWM-BLU 0
6,PS-ON 0 Pins
8 &10-gnd
As in OP With Only Back light & Power Board connected Didn't get any Back lights,So then tested BLs with BL tester And Back light came on.

Any help or troubleshooting ideas or testing to try next would be greatly appreciated

[R_J]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

Monitor the voltage on BB9003, next to CNL802, when you first turn on the tv, what is this voltage? it should come up to around 325vdc, I suspect you have a bad led in the backlight string.

[TKF]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

Thanks for help R J I have to turn tv on with plug Not sure if your refiring to pin 1 on CNL802 or the inductor in front of CNL802 the voltage on pin1&2 with BL not connected 419v with MB connected it 452v on pins 1&2 all other pins 0 and with BL plugged in 0v

[R_J]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

You have an open backlight string, that is why the voltage is high (419~452v) and it then goes into over voltage protection. It only take one led to fail and those backlight testers do not check the backlights at high current, only at about 10ma

[TKF]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

R J I was afraid it was a BL issue I remember reading somewhere about the protection in my testing Voltage i thought it might be MB do to the low reading on
Pin 4 PWM-BLU -0.75v with MB connected I will report back when i get it apart and repaired
Thanks again for your expertise

[TKF]

Re: Samsung BN44-00775A no Power No STB or Power lights.Help needed

You have an open backlight string, that is why the voltage is high (419~452v) and it then goes into over voltage protection. It only take one led to fail and those backlight testers do not check the backlights at high current, only at about 10ma

Update: Hope this info. can help others - R J you hit it right on the head the top string was shorted all leds out, all but 2 strings had bunt Leds and those 2 strings were all good. Replaced all led strings, and everything worked got STB light and power lights and tv working again just to see a new Big Problem the screen had horizonal lines on the upper part and other parts had color issue so started checking the I reseated ribbins on the t con and Driver board on bottom the driver ics (i think there called)the tabs on the side on the screen, 1 had a little tear and 1 at the top was missing. not sure if that was on pupose on not. when searching saw a videos of someone replacing ic tabs, not sure if the screen is Toste or can be repaired Has anyone had any luck repairing screens with these issue?
Thanks again R J and for any suggestions on the new issue.