47LN5400 2 seconds to black

[madcow007]

I have a 47LN5400 that will turn on however the backlight will only flash momentarily. I'm reading around 77v on the LEDs but output should be around 100v.

I have found a reasonably priced power supply but would love a second opinion before pulling the trigger.

Thanks

[budm]

Re: 47LN5400 2 seconds to black

What voltage (with ref to GND)do you get without the LEDs connector in place, did it jump up to > 77VDC first and then settle down to 77V.
Very common failure in TV with LED backlights are due to fail LEDs.

[madcow007]

Re: 47LN5400 2 seconds to black

At power on I get roughly 100v then settles to 77v I have similar result with LEDs disconnected.

[budm]

Re: 47LN5400 2 seconds to black

That means the circuit went into shutdown due to no load or very light load to protect itself from putting too high output voltage.

[madcow007]

Re: 47LN5400 2 seconds to black

Would this indicate bad LEDs? Are there any other trouble shooting steps you would recommend?

Thanks

[newtothis]

Re: 47LN5400 2 seconds to black

Yes, since the LEDs have failed they aren't drawing any/enough voltage so the system shuts down.

[madcow007]

Re: 47LN5400 2 seconds to black

Thanks for the help guys guess this one is destined for the dump pretty sad really isn't very old