Toshiba 50L4300U Backlight

[Eyes.Only]

The backlight flashes very quickly on power up but that's it. Can see the menu with light. This unit doesn't have an inverter board so is it the main power board? Or could it all flash quickly because the feedback/return wires are indicating a faulty led and is turning off?

[dskall]

Re: Toshiba 50L4300U Backlight

Well with LG panel I would suspect bad leds. You can check your voltages at P803 each side when you first power on and see max voltage on each L1and L2

[nickmatine1]

Re: Toshiba 50L4300U Backlight

this one has same power supply with 50l1350uc

[Eyes.Only]

Re: Toshiba 50L4300U Backlight

Checked the voltages and it does appear to be the LEDs. I took the diffuser out and did a power on test and the center bars don't flash, just the top and bottom ones. Do you guys suggest a stack method or just new strips?

[finntricky]

Re: Toshiba 50L4300U Backlight

check each LED to see if it lights up, because it may just be the connection blocks on the strips that are not making good contact.

[dskall]

Re: Toshiba 50L4300U Backlight

Numerous ways to repair depending on how you want to do it. You can replace strips. Buy a strip and cut it up for stacking or buy just leds and replace. Those are on order of time and skill level. There are youtube videos on each.

[Andrew F. Ali]

Re: Toshiba 50L4300U Backlight

It will be less costly to apply Reecey's Stack Method, which is a proven fix. If it is more than 2 LEDs, I will recommend a new strip replacement. After repairing the backlights turn down the Backlights Level control to about 75% and that should prevent further issues.

[diif]

Re: Toshiba 50L4300U Backlight

I think your TV is edge lit. You'll have to replace the faulty LED(s) or the whole strip.

[Andrew F. Ali]

Re: Toshiba 50L4300U Backlight

I think your TV is edge lit. You'll have to replace the faulty LED(s) or the whole strip.

+10..Get whole strip...best bet.

[budm]

Re: Toshiba 50L4300U Backlight

The way the chassis looks, it does not look like edge lit panel.

LC500DUE-SFR1
http://www.shopjimmy.com/lg-6916l-12...strip-only.htm
http://www.shopjimmy.com/lg-lc500due...-12-strips.htm

You may want to verify.

[finntricky]

Re: Toshiba 50L4300U Backlight

Defo not edge lit, normal vestal back light strip LED's,
like i said, check each LED first,
6 rows of LED's = 12 strips in total,
12 plastic connection blocks, loads of soldering,

[diif]

Re: Toshiba 50L4300U Backlight

My bad, this review here has it as edge lit.
https://reviews.lcdtvbuyingguide.com...-50l4300u.html

[Eyes.Only]

Re: Toshiba 50L4300U Backlight

So the first leg which is the top two sets and the bottom set all appear good.

The second leg however is bad. I tested as individual strips.

L1: All good > R1: 1 bad LED
L2: all bad > R2: All good
L2: had 2 bad LEDs > R2: 1 bad LED

Is that many bad LEDs common? Should I just get a set of strips? Should I replace all of them if others are soon to follow? (Why only the second leg? Power board surge or something?)

[dskall]

Re: Toshiba 50L4300U Backlight

L2 probably not all bad. An open led can disable the whole strip. Would need to test each one in that strip.

[budm]

Re: Toshiba 50L4300U Backlight

So the first leg which is the top two sets and the bottom set all appear good.

The second leg however is bad. I tested as individual strips.

L1: All good > R1: 1 bad LED
L2: all bad > R2: All good
L2: had 2 bad LEDs > R2: 1 bad LED

Is that many bad LEDs common? Should I just get a set of strips? Should I replace all of them if others are soon to follow? (Why only the second leg? Power board surge or something?)

They drive those LEDS real hard close the max spec they can handle, and with poor heats management it does not help.
So ONLY two bad LEDS? that is nothing. It is a big panel so it kind of taking chance that other LEDS may go out later on too, you can replace them all of just the bad ones and run the backlights level as low as you can to extend the life of the LEDs.

[Eyes.Only]

Re: Toshiba 50L4300U Backlight

Any tips on the best place for a set if I were to replace them all?

[hisalive]

Re: Toshiba 50L4300U Backlight

Good Day Eyes.Only

Did you happen to replace the LED strips? Did you get this set working? I have same issue and looking for best place to purchase new strips!

Thanks

[Eyes.Only]

Re: Toshiba 50L4300U Backlight

Yep I did. By replacing the bad strips everything was fixed. I was only able to get a full set so now I have many I did not use. Do you know which strips you need?