Toshiba 58L1350UC Backlight.

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

Go ahead and test them just like RJ describes in post #34 in this thread: https://www.badcaps.net/forum/showthread.php?t=116512

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

Seems like we're going over this constantly, these simple backlight testing methods should probably be in a sticky thread.

[tantogata]

Re: Toshiba 58L1350UC Backlight.

I've checked every lines (each line consist of 11-12 leds). There is no voltage between + and - on the LED connector of power board.

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

Maybe if you didn't already, try unhooking the backlight cable at powerboard and check the pins on powerboard, see if they are still 0, if so it would seem like a powerboard issue, unless it's a more complicated circuit as described below.

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

This is RJs post 34 on the thread I linked for checking: "The backlight circuits are all different, some have Over Voltage Protection, some have Under Voltage Protection, and Current monitoring, some circuits use all.
The best way to test the voltage is across the + and - of the led connector (in this case) You must monitor this voltage as the tv is turned ON,
In this case the board spec is 85v under normal operation, The fact it peaks at over 100vdc suggests the led circuit is going open and the circuit detects an Over voltage and shuts off the boost circuit, the 60vdc is just the raw dc supplied to the drive circuit.
This is a very simple led drive circuit used on this board, some circuits are more complicated as in multiple strings and the circuit can check the current faster than you meter reacts and if the led current is wrong, the boost circuit may not even start.
Others have a constant supply voltage and only control the return path of the led string"

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

Seems like we're going over this constantly, these simple backlight testing methods should probably be in a sticky thread.

Anyway I won't be going over the procedure every other thread, it's just too DAMN boring having to say the same thing all the time.

[tantogata]

Re: Toshiba 58L1350UC Backlight.

I've checked everything what I could. That's why I changed the power board - didn't help. Changed the main board - didn't help.

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

Try the test in post #24 on both powerboards if you have 2, also follow post #25, read it over a few times, then test both boards, seems like there should be some differences in your measurements that you can decipher.

[tantogata]

Re: Toshiba 58L1350UC Backlight.

I've changed all led strips for new ones - not fixed, the same issue - short flash the screen and darkness.

[nomoresonys]

Re: Toshiba 58L1350UC Backlight.

You have an image, so tcon seems good, possibilities that members have already mentioned and the things that could be wrong include, backlight circuit issue, only way to confirm all connections is tear down to backlights, panel must be treated very gently, easy to break/crack them for sure, you already did it, so you know, it's for those looking on who might not know. Other possibility is you bought a defective mainboard that isn't sending backlight on signal, make sure cable from powerboard to mainboard is all good, continuity on all wires, maybe check that the backlight driver IC on powerboard is putting out what it should, like mentioned these toshibas are junk and not worth much of an investment.

[tantogata]

Re: Toshiba 58L1350UC Backlight.

Changed T-CON board - no good result. I'm tired with this piece of garbage. No more patience and time to reanimate this dead body. Thanks to everyone for helping me.