Seiki LED TV SE50UY04 Backlight Issues

[Johnnny5]

New to the form. So I have a question I have a LED TV where when I turn it on blue light indicator comes on stating its on Seiki logo appears for a few seconds and looks good but then the back light goes out. I used a flash light and can see content and able to toggle through the source and menu options just fine. Since the back light comes on dont think its my LED's on the unit but possible the LED Driver Board. Is anyone able to confirm this? If Im not mistaken if it was the main board or T-Con I wouldn't be able to see anything correct? Unable to validate sound as Im having a hard time toggling through the menu blinded to get my Playstation to communicate with the TV. It looks like I have to go through the configuration menu before getting to the source output from what Im seeing.

Any help would be greatly appreciated. Thank you

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

1) First, we need good clear pictures of the whole back side of the TV showing all the boards so we can see what we are dealing with.
2) It can still be backlights if some of the LEDs shorted the LED's string (LED's are connected in series) will still light up but the backlights protection circuit will kick in due to shorted LEDs. If the TV is using more than one LED string so if one of the LED of bad string has gone open circuit, but the good string will still light up, but the output Voltage of the bad string that has open LED will go too high then the protection circuit will kick in.
You need to troubleshoot the problem by at least taking the Voltage measurement and good visual inspection to narrow down the problem/s.
What is your experience level? Do you have proper tools?

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

1) First, we need good clear pictures of the whole back side of the TV showing all the boards so we can see what we are dealing with.
2) It can still be backlights if some of the LEDs shorted the LED's string (LED's are connected in series) will still light up but the backlights protection circuit will kick in due to shorted LEDs. If the TV is using more than one LED string so if one of the LED of bad string has gone open circuit, but the good string will still light up, but the output Voltage of the bad string that has open LED will go too high then the protection circuit will kick in.
You need to troubleshoot the problem by at least taking the Voltage measurement and good visual inspection to narrow down the problem/s.
What is your experience level? Do you have proper tools?

Im not a pro or electrician but I can say Im a DIY. If this was a car or motorcycle wouldnt be an issue so I would say Im mechanically inclined to a certain extent.

Ill try to see if I can get the backing off and attach a picture later tonight. I have tools but dont have a LED tester so wont be able to test the strings. If Im not mistaken this TV has a left and right string of LED's. If it was to be one of the LED's on the string wouldnt the picture quality show some signs of a dead LED light when its on the logo screen??? I can test the voltage but not sure what Im looking at in voltage or where I should be testing? Any idea of what and where I should be testing when its open? Your response does make sense if it is one of the LED lights causing the protection to kick in.

Thanks again for the assistance

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

I cannot tell you where to test until we see the pictures.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

You need to remove that black cover on top of the LED driver board and then take good clear straight shots of the whole LED driver board.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

You need to remove that black cover on top of the LED driver board and then take good clear straight shots of the whole LED driver board.

Took a look at everything and it looks good. All caps appear to be fine from what I can see

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

That LCD panel has 16 LED strings (you can see 16 LED driver circuits), so you need to make lots of Voltage measurement on that board, it is not going to be easy for beginner.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

That LCD panel has 16 LED strings (you can see 16 LED driver circuits), so you need to make lots of Voltage measurement on that board, it is not going to be easy for beginner.

I'm not even sure what I'm looking for. Anyway you can point me in the right direction?

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

Ok so got an update...I was playing around with the two smaller plugs in the picture which I believe is for the LED's. Looking at the picture it would be the top right plug. Does anyone know what that goes too? I noticed when I remove that wire the TV lights up and appears to be working just fine. When I reconnect it goes to the logo and shuts off again?

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

https://www.badcaps.net/forum/attach...569638141Those two connectors go into the panel where the LED strings are, you can see the pins are labeled with VLED+, VLED -.
So if you remove them then there will be no backlights, so I am not sure what you mean "I remove that wire the TV lights up and appears to be working just fine."

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

https://www.badcaps.net/forum/attach...569638141Those two connectors go into the panel where the LED strings are, you can see the pins are labeled with VLED+, VLED -.
So if you remove them then there will be no backlights, so I am not sure what you mean "I remove that wire the TV lights up and appears to be working just fine."

I removed one of the connectors and got a display.




I’m sure I still have an issue but trying to figure out if it’s the board or the led strip

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

I removed one of the connectors and got a display.




I’m sure I still have an issue but trying to figure out if it’s the board or the led strip

OK, put the cable back in place, TV unplugged. Set meter to Ohm mode, start at 200 Ohms scale first, then keep black probe on the chassis then red probe on each one of those test points I marked, make sure you are making good contact to those test points.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

OK, put the cable back in place, TV unplugged. Set meter to Ohm mode, start at 200 Ohms scale first, then keep black probe on the chassis then red probe on each one of those test points I marked, make sure you are making good contact to those test points.

Ok so when I checked with the meter I got 70.8 from x and y. Couldn't get any reading from any of the other ones.

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

70.8 Ohms?
Now disconnect both cables and test X and Y again.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

They seem to be around the same. The meter I have is digital and have it on auto ohms so not able to test it at 200 ohms like you were wanting. It sure if that makes a difference. I’ll see if I can borrow a neighbors tomorrow and retest it.

[budm]

Re: Seiki LED TV SE50UY04 Backlight Issues

We need to know what Ohms scale you are using, right now we do not know if the readings are in Ohms, K Ohms, M Ohms.
I.E. 70.8 Ohms? 70.8 K Ohms? 70.8 M Ohms?
The reason I have you check all those test points is to find out if any of them has low Ohms reading or dead short to chassis GND or not, especially on the one that makes the backlights work when disconnected.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

We need to know what Ohms scale you are using, right now we do not know if the readings are in Ohms, K Ohms, M Ohms.
I.E. 70.8 Ohms? 70.8 K Ohms? 70.8 M Ohms?
The reason I have you check all those test points is to find out if any of them has low Ohms reading or dead short to chassis GND or not, especially on the one that makes the backlights work when disconnected.

Sorry for the delay feeling under the weather. I rechecked and ran through the Ohms and this is what I got 70.8 K Ohms. Also got .23 and .069 M Ohms Both appears to be consitent with X and Y. The other ones you asked I still cant get any readings from them.

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

Any updates on what could the issue?

[Johnnny5]

Re: Seiki LED TV SE50UY04 Backlight Issues

We need to know what Ohms scale you are using, right now we do not know if the readings are in Ohms, K Ohms, M Ohms.
I.E. 70.8 Ohms? 70.8 K Ohms? 70.8 M Ohms?
The reason I have you check all those test points is to find out if any of them has low Ohms reading or dead short to chassis GND or not, especially on the one that makes the backlights work when disconnected.

Bringing back an old thread as I sort of just pushed this off due to work and other projects. Anyways any other things we can try testing?