TCL LED backlight voltage drop

[Alex9]

Re: TCL LED backlight voltage drop

LED tester connected to pins 5 or 6 and pins 1 or 2 all light up the board at 60v. It seems 5-6 and 1-2 are connected.

I tested pin 2 again to see if the readings match pin 1 and got these readings:

24v, .9v (with BL flash), 1.5v

The tv came on with full backlight for about 20 seconds this morning when I plugged it in.

[budm]

Re: TCL LED backlight voltage drop

I am confused, if you pull the female connector of the board then use the tester between pin 2 and either pin 5 or pin 6 of the female connector and you see the tester shows 24v, .9v (with BL flash), 1.5v?

Pin 1 and pin 2 will be tied together only when it is plug into the male connector of the board, same for pin 5 and pin 6.

[budm]

Re: TCL LED backlight voltage drop

BTW, the panel is still apart so you can actually see the LEDs?

[Alex9]

Re: TCL LED backlight voltage drop

Sorry, I had the tv put together due to lack of working space. I just took it apart though.

strip 1 is 19.3v with 7 LEDs
strip 2 is 22v with 8 LEDs
strip 3 is 19.3v with 7 LEDs

They appear to be connected in Series.

Soooo I put it all back together and for some reason the backlight is staying on now. It's been 10 minutes already without turning off. The only thing I can think of is that I disconnected each LED strip from each other to test them individually just now and maybe reconnecting one of them fixed a loose connection problem? I don't know what to say except that I'll post back if it stops working?

[Alex9]

Re: TCL LED backlight voltage drop

The backlight just went out again. It happened when I connected a vga cable between it and my computer. Not sure if that's related or a coincidence.

[Diah]

Re: TCL LED backlight voltage drop

i would suggest you to connect all the Cable direct on the LED strips jump the sockets .. , its more safe for future and best way to be sure all connection exist.

[frankrizo]

Re: TCL LED backlight voltage drop

So I have a simaliar problem, I think its the power supply board, I dont have a tester to test all the led strips. my voltage, with led conector unplugged, starts at 100 and drops to 35 volts dc. then stays there, with and without led connector connected.
Bad Cap??? Father in law had his tv do the same thing, his was a 2 amp part the guy replaced, part was 2 pounds, labor was 80....

anyway. if you need photos, how do i upload?
and, how do i test led strips without an led tester? i do have some things around the house...maybe to test them...


hope someone can help.

cheers
frank

[budm]

Re: TCL LED backlight voltage drop

So I have a simaliar problem, I think its the power supply board, I dont have a tester to test all the led strips. my voltage, with led conector unplugged, starts at 100 and drops to 35 volts dc. then stays there, with and without led connector connected.
Bad Cap??? Father in law had his tv do the same thing, his was a 2 amp part the guy replaced, part was 2 pounds, labor was 80....

anyway. if you need photos, how do i upload?
and, how do i test led strips without an led tester? i do have some things around the house...maybe to test them...


hope someone can help.

cheers
frank

The LED drive Voltage went up to 100V and then dropped down to around 35V because the circuit detected no load, you have open circuit in the LED strings some where.