Samsung UN50EH5300FXZA, black screen

[Arn241976]

According to the people present at the time, it just turned off. So I assumed the power supply was bad. I ordered one off of eBay (supposedly out of a new TV with a cracked screen), but it didn't fix the problem. The standby light is on, and when I press the power button on the remote, the standby light blinks 4 or 5 times.

I've looked for a datasheet for both the TV model number and for the main board model number (BN94-06882C) but neither are listed. I hate to keep playing "SwapTronics" and just buy a new main board without knowing if there's a way to test it. I have a multi-meter, but I'm not a pro by any means.

Any thoughts on how to proceed?

Thanks in advance!

[budm]

Re: Samsung UN50EH5300FXZA, black screen

If you unplug the cable between the main board and the power supply board then plug the TV into the outlet, do get the backlights to come on and stay on? If it does, then the power supply/LED driver board is OK and the problem is on the main board.

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Thanks for reply! I tried unplugging the cable between the power and main board, but no luck. Still have a black screen. What's next the next thing to check?

Thanks again!

Aaron

[budm]

Re: Samsung UN50EH5300FXZA, black screen

No glowing lights from the back of the panel at all?

Need P/N of the power supply/LED driver board, BN44-??????

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Bn44-00668A

[budm]

Re: Samsung UN50EH5300FXZA, black screen

OK, leave the cable to the main board disconnected, power the board then check the DCV using chassis as the ground ref for the meter, then measure the DCV on the connectors:
CNM803 (it has ODD and EVEN row for the pin numbers)
Pin 1 (B13V) =
Pin 13 (B5V) =
Pin 6 (BLU-ON) =
Pin 12 (A5V) =
Pin 14 (PS-ON) =

CNL802:
Pin 1 (D+) =

Pictures provided by SHOPJIMMY.

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

It'll have to be tomorrow afternoon, but will do. Thanks again!

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

No glowing lights from the back of the panel at all?

Need P/N of the power supply/LED driver board, BN44-??????

Sorry, missed your question about the glowing lights. No, no light at all.

Thanks.

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Here are the voltages you asked for:

Pin 1 (B13V) = 12.5
Pin 13 (B5V) = 5.35
Pin 6 (BLU-ON) = 3
Pin 12 (A5V) = 5.35
Pin 14 (PS-ON) = 3.35

CNL802:
Pin 1 (D+) = 331.4

These were measured from the original board, not the replacement that I purchased.

Thanks again!

Aaron

[budm]

Re: Samsung UN50EH5300FXZA, black screen

Here are the voltages you asked for:

Pin 1 (B13V) = 12.5
Pin 13 (B5V) = 5.35
Pin 6 (BLU-ON) = 3
Pin 12 (A5V) = 5.35
Pin 14 (PS-ON) = 3.35

CNL802:
Pin 1 (D+) = 331.4

These were measured from the original board, not the replacement that I purchased.

Thanks again!

Aaron

Is that 331.4VDC with the LED connector in place? if it is, you have open circuit in the LED string some where, more likely bad LED/s.
The LED Voltage with load is 229V as shown in the Voltage chart on that power supply/LED driver board.

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

With the power board plugged into AC, I get 331v regardless if that connector (CNL802) is plugged in or not. If I plug in the cable to the main board (CNM803) and hit the power button on the remote (going from standby to on) the voltage drops to about 233v (slowly I might add, it took 10 to 15 seconds to fall from around 260v).

Thank you!

Aaron

[budm]

Re: Samsung UN50EH5300FXZA, black screen

You have open circuit in the LED string.
Can you read the model number of the LCD panel sticker?

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Is this what you're referring to?

[budm]

Re: Samsung UN50EH5300FXZA, black screen

Is this what you're referring to?

Yes. LED strips for SAMSUNG CY-DF500BGMV1H Panel
http://www.usefulparts.com/tv-parts/...h5300fxzc-bj06

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Do I replace them all, or do I need to test for the bad one?
These are out of stock at the link you provided; any other ideas as to where to get them? My searching proved futile.

Thanks again for your help! I would've just ordered a main board and been out $60.

Aaron

[budm]

Re: Samsung UN50EH5300FXZA, black screen

You can test each strip to narrow down as to which strip is bad.
There is no way to tell how much life the other working strips are and the condition of the used strip. It is kind of a gamble, all you can do after getting the TV to work is to turn down the backlights level to as low as you can but still get good pictures, this will help extending the life of the LEDs.
At this point you need to get to the LED strips to really verify what you have first. You may have just one bad LED, which is then it can easily be repair using stacking method.
50" is a big panel so you will probably need two people to handle the glass panel.
Reece has lots of Video on how to do the stacking replacement of the LED or replacing the LED using proper tools.

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Thanks, I'll try to start the disassembly this weekend, and I'll look for Reece's videos.

Thanks!

[vinceroger69]

Re: Samsung UN50EH5300FXZA, black screen

https://www.youtube.com/user/MrReeceyburger123/videos

[Arn241976]

Re: Samsung UN50EH5300FXZA, black screen

Thanks for the video link, very helpful!

So, if I decide to do the stacking method, can someone recommend the best LED strip to buy for this?

Thanks.

[budm]

Re: Samsung UN50EH5300FXZA, black screen

Get the lowest price you can find as long as the seller is good. They are built just about the same, the main key is that to turn down the backlights level to as low as you can.
http://www.ebay.com/itm/Samsung-LED-...0AAOSwhOVXeGNK

http://www.ebay.com/itm/2Pcs-set-LED...UAAOSw7XZXhFK1