Total noob here - No backlight for Samsung LED TV; help please


	FORUM HOME	SEARCH POSTS	WHO'S ONLINE	LOG IN	RULES F.A.Q.

TV Forums: TV Equipment: TV Repair Forum:
Total noob here - No backlight for Samsung LED TV; help please

Print Thread

leatherlunch
New User

Sep 13, 2016, 5:37 PM

Post #1 of 10 (3575 views)
Shortcut

Total noob here - No backlight for Samsung LED TV; help please	Can't Post

Hey everybody,

Bear with me. I'm a complete neophyte at this stuff but I'm game to learn.

I recently inherited a Samsung UN32F5500AF unit from someone. They said the picture was dead but they could still hear the sound, but had no idea what to do with it. I said I'd take a crack at fixing it. In the past, I've opened up my computer monitor when it seemed dead and changed up the capacitors, so I had hoped this would be the same relatively easy fix. It doesn't look to the be the same issue here.

There is indeed sound coming through the speakers, and I can see little blue LED lights behind the ventilation grate in the back, as well as a red light on one of the sound plugs. Also, I noticed that the screen does display, although without lighting up. I happened to see "HDMI 1" very faintly when it was angled to the window and then performed what I believe you guys call "the flashlight test" and indeed the pixels seems to fire but no light comes through.

So, when I opened it up and looked around a bit I didn't see anything that stood out. No evidence of arcing, no bulging capacitors, nothing out of the ordinary to my noob eyes. This isn't a great picture, but at least it can be used for directions. I'll take a close up of anything anyone recommends for clarity.

I'm assuming the motherboard on the left is the "thinker", the electrical board on the right is the "doer", and the small board on the bottom is the sound card.

Can someone please help guide me a little bit on what things to test first. Bear in mind, I don't have any equipment to test things like electrical signals, but maybe I can borrow one somehow if it's completely necessary.

What's the first thing I should do?

Thanks in advance!

jts1957
Veteran

Sep 13, 2016, 6:54 PM

Post #2 of 10 (3572 views)
Shortcut

Re: [leatherlunch] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

Unplug Main board to Power/LED driver board cable at either end. See IF screen lights (and stays lit). IF NO = Bad LED(s) inside the Panel/Screen (Power/LED Drive board is a lesser percentage failure).

https://www.youtube.com/watch?v=q8W8m_Xa-Lo

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Sep 13, 2016, 7:04 PM)

leatherlunch
New User

Sep 14, 2016, 1:57 PM

Post #3 of 10 (3538 views)
Shortcut

Re: [jts1957] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

Thanks for the video link. I've watched a couple by that guy and have found some education in them. I have a few questions now as a result.

So, what I'm looking at in that photo is as follows, correct?
The large green board is the main board.
The large tan board is the power board.
The small green board in the lower middle is the LED Driver/Backlight inverter.

Does that mean the T-Con board is the series of little green boards that look like RAM chips, running along the bottom of the unit?

He mentions in the video you cited that the issue was most likely with either the LED Driver, the power supply board, or the LED lights themselves. I'll try to take the main and power board up to look at the bottom for evidence of arcs or other bad stuff.

You say above "unplug the main board to the Power/LED Driver board" - do you mean I should unplug all the boards from each other, other than the T-Con board (where ever that is)? That's three boards you mention there, right? Also, how would the screen light if the power board isn't connected to anything?
Finally, when you say "See if screen lights" do you mean the faint lettering detectable by the flashlight test?

Thanks for your help jts1957. :)

EDIT: From what I'm seeing on shopjimmy.com's website, that small green board on the bottom/middle looks like the T-Con board. So, where's the LED Driver then?

(This post was edited by leatherlunch on Sep 14, 2016, 2:12 PM)

leatherlunch
New User

Sep 14, 2016, 2:31 PM

Post #4 of 10 (3534 views)
Shortcut

Re: [leatherlunch] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

Okay, now I think the picture is getting a little more clear. The tan board on the right is a combination of Power board and the LED Driver in-one, right?

jts1957
Veteran

Sep 14, 2016, 6:51 PM

Post #5 of 10 (3525 views)
Shortcut

Re: [leatherlunch] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

I believe I said:

Quote

Unplug Main board to Power/LED driver board CABLE at either end.

Quote

See IF screen lights (and stays lit).

With the Power/LED Driver board plugged into AC and unplugged from the Main Board, the manufacturer has arranged that if nothing is wrong with the Power/LED Driver board OR the LEDs inside the LCD Panel, the back lights will light (and stay lit). Since the Main board is disconnected there will be NO Sound/NO video and NO controls operating, just LEDs lighting which should be easily viewable from the front or rear of the panel assembly.

You have figured the boards correctly. (The boards along edge are Gate or Source drivers for the TFT.)

-------------------------
Location: Far, Far Away

leatherlunch
New User

Sep 17, 2016, 6:27 PM

Post #6 of 10 (3504 views)
Shortcut

Re: [jts1957] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

I haven't had a chance to crack the unit open again and tinker with it. Hopefully tonight or tomorrow and I'll report back. Thanks for your help so far jts. :)

leatherlunch
New User

Sep 21, 2016, 3:30 AM

Post #7 of 10 (3485 views)
Shortcut

Re: [jts1957] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

Okay, I did what you instructed and there was no light up. When I plugged it all back in as normal the flashlight test was the same as before. So, according to what you said that means the LEDs are kaput. How hard is it to replace those, on a scale of 1 to 10, given that I'm new to this? I see on the shopjimmy.com site that these parts are about $55.

(This post was edited by leatherlunch on Sep 21, 2016, 3:34 AM)

jts1957
Veteran

Sep 21, 2016, 4:21 AM

Post #8 of 10 (3481 views)
Shortcut

Re: [leatherlunch] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

https://www.youtube.com/watch?v=RDsLi6d4oGI

I don't see ANY $55.00 LEDs at SJ: http://www.shopjimmy.com/samsung/un32f5500afxza

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Sep 21, 2016, 4:26 AM)

leatherlunch
New User

Sep 21, 2016, 1:52 PM

Post #9 of 10 (3464 views)
Shortcut

Re: [jts1957] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

I found these when I did a search for that Samsung model, but they're out of stock. Is it the wrong product anyway? http://www.shopjimmy.com/...-strips-5-strips.htm

(This post was edited by leatherlunch on Sep 21, 2016, 1:55 PM)

jts1957
Veteran

Sep 21, 2016, 2:01 PM

Post #10 of 10 (3458 views)
Shortcut

Re: [leatherlunch] Total noob here - No backlight for Samsung LED TV; help please [In reply to]	Can't Post

It's same as one in my previous link. ($45)

Includes 5 strips.

PLEASE NOTE: There are multiple different versions of the TV model shown. Please confirm that these strips are found in your TV before purchasing.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Sep 21, 2016, 2:02 PM)

Print Thread

Search for (options)

- Page loaded in: 0.22 s on (CGI/1.1)