TCL 55s405 no backlight

[speter]

I have a TCL 55s405 TV with the back light out, there 4 wires to the backlight(pic to follow) I would like to test the led strips without taking the set apart
How can I find out the proper voltage to power the strips?
So far I cannot find service info on the set.
I have sound, and picture with a flashlight

[Diah]

Re: TCL 55s405 no backlight

be brave and ask friends to help you take the screen apart. you can spend money and waiting time of led tester.. but of sure you will need the asking of friends help. this advice free of charge

[budm]

Re: TCL 55s405 no backlight

I have a TCL 55s405 TV with the back light out, there 4 wires to the backlight(pic to follow) I would like to test the led strips without taking the set apart
How can I find out the proper voltage to power the strips?
So far I cannot find service info on the set.
I have sound, and picture with a flashlight

Show us the pictures of the whole backside of the TV so we can see what we are dealing with.
Also good clear straight shots of the power supply/LED driver board.

[speter]

Re: TCL 55s405 no backlight

I figure it's pretty hard to measure the voltage out to the LED strips, because the PS shuts down very fast, so I can easily power the strips from the connector, and see if it's the leds light, or power supply is bad.
I hear you about dismantling the panel

[budm]

Re: TCL 55s405 no backlight

OK, you have 4 wires for the LED's.
1) TV is off, set Volt meter to 200VDC scale, all connectors in place.
2) Keep black probe of the meter on the chassis.
3) Keep red probe on one of the 4 pin of the LED connector.
4) Turn on the TV while watching the meter to see how high the Voltage jumps up to before it goes into shout down, then turn off the TV and wait 10 seconds.
5) Repeat the same test on the other 3 wires.
6) Report the result of each test.

[speter]

Re: TCL 55s405 no backlight

Top wire (black) goes to 200 -300 volts (my meter is pretty slow) Pin 9
Second wire(red) always 0 Pin 7
Third wire (white)always 0 Pin 4
Bottom wire(red) goes to 40 - 65v Pin 2

[budm]

Re: TCL 55s405 no backlight

You have open circuit (bad LED, bad connection between LED strips, bad wires, etc) for the LED current path to complete that is why the Voltage went up to 300V.

[speter]

Re: TCL 55s405 no backlight

Thank you!
My daughter smashed our Vizio 55 and I am going through some TVs that a friend gave me, looking for an easy fix for a replacement.
Tomorrow I'll try a 60 Samsung with no power, sooner or later we will be watching again

[nomoresonys]

Re: TCL 55s405 no backlight

Yes, break out the sammy, backlight replacement is pretty much the hardest job on tvs.

[speter]

Re: TCL 55s405 no backlight

The Samsung had shorted LEDs. The set of 2 LED strips came in, but I had to improvise a tester with my bench power supply and a series resistor of 500 ohms to test the strips.
I replaced the bad strip, and let the LEDs run a couple of minutes, and put it back together.
I put it on the TV stand and it had a small flash of the LEds and it was out again..sigh...
I took it apart again, and another string of the same type(4 LED VS 5 LED) so I didn't have the part. I ended up removing 1 good LED from the first bad strip, and installing it on the other bad strip. and the set is working, it has been playing for 6 hours now.

[nomoresonys]

Re: TCL 55s405 no backlight

Nice work, now turn down the backlights, NOT brightness to as low as you can tolerate, I run my samsung on 8, it goes up to 20 but 20 will wear out your leds much faster.

[speter]

Re: TCL 55s405 no backlight

I can't get into settings yet until the remote arrives tomorrow, watching it through the demo popup for the moment.

[nomoresonys]

Re: TCL 55s405 no backlight

I operate mine with a 7 dollar philips universal remote, it seems to work every section.

[speter]

Re: TCL 55s405 no backlight

I wasn't sure which universal remote would have all of the functions, so I ordered the one for the TV for about the sane price, If I knew the universal would support every function, I would have gone that way, as this TV could die tomorrow in a worse way

[motterpaul]

Re: TCL 55s405 no backlight

As long as a universal remote has a "menu" button it should work for your purposes. I found that finding the network helped a lot to getting my Vizio remote up & running again, but there was no "menu" button on the TV. Using an alternate remote "menu" button got the TV remote working again.

[speter]

Re: TCL 55s405 no backlight

TV was good till 3 weeks ago, and it burned out another LED strip, I replaced it, and it is running again. I had already bought a LED kit last time, now I finally was able to put it to use.