Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

The big blue cap is measuing 389v. Each LED strip is measuing 17v. If I measure the spot at the beginning of the strips in the area of the connection cable to the P/S board, those points measure 38v.

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

I did mention that all of these readings are with the connection between P/S board and main board unplugged, right?

[budm]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

I like to know how all the the strips are connected, the longer strip is connected to the shorter strip so you have 4 big long strips and 4 connectors?
and this one "Each LED strip is measuing 17v" on all 8 strips?

" If I measure the spot at the beginning of the strips in the area of the connection cable to the P/S board, those points measure 38v." so 38v x 4 = 152V.
Each set of strip has 15 LEDs = 45V per set

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Here is an illustration (see attachment) to show the points I'm measuring on the strips and the associated voltage readings. Hope this helps. I really appreciate the help.

[dskall]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

What do they do when you push power button?

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Would pressing the power button do anything if I have the P/S board disconnected from the main board? Or would I need to reconnect this cable as well as the cable that controls the power button to the main board?

[dskall]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

How are you getting your voltage measurements? You can connect everything up minus panel and leds should flash and you can see if all light

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

I just hooked everything up, P/S connected to LED, P/S connected to Main Board, Main Board connected to power button. Once I turn the TV on, the LED lights up the same as they did without connection to the Main Board (with the flicker) and the voltage readings are the exact same on all the LED strips.

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

If the flicker is a result of not enough voltage from the P/S board to the LEDs, is there a way to determine what part of the P/S board is causing the issue? I'm surprised since I get the same results with the backup P/S board I purchased on ebay. I suppose I could have two bad P/S boards. It just sounds like you guys are suggesting the voltage to the LEDs is less than expected, so I want to figure out why.

[dskall]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

When you push the power button the leds come on briefly not stay on right. And all leds are lit?

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

When I press the power button the lights come on, and stay on, with the same flicker. All LEDs are lit, and the flicker is consistent across each LED.

[dskall]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Have you tried these from manual.
If your Samsung Television is flickering or dimming sporadically, you may need to disable some of its energy efficient features like the Eco Sensor or the Energy Saving feature. If you follow below step with your remote, you can turn these features off or on. y Energy saving : User Menu ĺ Setup ĺ Eco Solution ĺEnergy Saving y Eco Sensor : User Menu ĺ Setup ĺ Eco Solution ĺ Eco Sensor

[budm]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Post 18:
"Do you still get over 300VDC if the LED string is not connected?"

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

budm, yes, still get over 300VDC if the LED string is not connected

[budm]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

That means the boost converter is working but some how with the load it goes down below normal Voltage

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Any way to isolate the issue? P/S board?

[dskall]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

May have a bad cap on boost circuit not able to keep up with load.

[kfitz]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

dskall and budm, thanks very much for your help. I wasn't sure where to begin troubleshooting the voltage issue on the boost circuit so I bought a new P/S board from ShopJimmy for $35. The backlights work perfectly. So there was definitely an issue with BOTH boards (the original and the one I bought from ebay, which I was able to return). All and all I spent about $100 for new backlights and a new P/S board. Much cheaper than buying a new TV. Thanks again guys.

[flashcode]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Hey kfits, with the new board did you still get +Vled = 300V (open circuit) with the LEDs disconnected? Thanks

[flashcode]

Re: Backlight Issue on Samsung LED Model UN50EH5000F (version AJ04)

Hey kfitz, with the new board did you still get +Vled = 300V (open circuit) with the LEDs disconnected? Thanks