Seiki 50 inch has no back light

[bluedawg]

HELLO EVERYONE I HAVE A SIMPLE QUESTION I AM GOING TO POST A PICTURE
AND ASK THAT IF SOMEONE CAN TELL ME IF THIS POWERBOARD IS ALSO THE INVERTER FOR BACK LIGHTS. I HAVE A SEIKI SE50FY10 THAT EVERY THING IS WORKING BUT NO BACK LIGHTS AND IF THE SMALL 4 CONNECTORS ARE GOINGTO BACK LIGHT INSIDE TV , THEY HAVE NO POWER ON THEM WHEN SET IS TURNED ON. THE PICTURE IS ON SCREEN THAT YOU CAN SEE WITH FLASHLIGHT TEST AND I HAVE SOUND. I CAN NOT FIND A INVERTER ON THIS TV ANYWHERE ELSE. ALSO IF THERE IS A WAY TO CHECK A COMPONENT ON THE POWER BOARD THAT TURNS ON THE BACKLIGHTS PLEASED PROVIDE ME WITH SOME GUIDANCE. THANK YOU IN ADVANCE

[CapLeaker]

Re: Seiki 50 inch has no back light

What is the model number of your TV?

[bluedawg]

Re: Seiki 50 inch has no back light

Se50fy10 model

[jetadm123]

Re: Seiki 50 inch has no back light

Your model is LED and does not use an inverter.

[Terryfictv]

Re: Seiki 50 inch has no back light

I am working on the exact same model. I have the power board ordered and when I get it next week I will help you. My symptom is click then blinking LED, subbed main board = no change.

[bluedawg]

Re: Seiki 50 inch has no back light

Jetadm123 Do u have any idea what turns on lights then and where I can test to see if there is power. Or does the power board turn on back lights?

[budm]

Re: Seiki 50 inch has no back light

The BL-ON signal is generated by the main board. There are no labels for the connectors pins at all so it will be very difficult to find the function of each pin. Look at the main board to see if there are labels for the connectors.
Can I see the good straight shot of the bottom side of the board?

[bluedawg]

Re: Seiki 50 inch has no back light

Budm, thank you for the response since i last posted I took the power board out and flipped it over and found all the pins to be labeled . I also found the pins where power leaves power board to go to led lights. But I accidently shorted out a resisistor and cracked it and it burnt one of the tiny tiny black little rectangle things directly underneath the resistor. Can u tell me the name of the tiny black rectangle things normally on the bottom of boards and the markings beside them normally start with a R? So now its gona take me tommorrow to figure out if i should just buy a power board for $50 and hope that would solve the original problem and the one I created? Any suggestions is greatly appreciated lesson learned on testing transistors in a tight spot

[budm]

Re: Seiki 50 inch has no back light

'R' = Resistor, but cannot tell more until we see the pictures.

[tw2005]

Re: Seiki 50 inch has no back light

Budm, thank you for the response since i last posted I took the power board out and flipped it over and found all the pins to be labeled . I also found the pins where power leaves power board to go to led lights. But I accidently shorted out a resisistor and cracked it and it burnt one of the tiny tiny black little rectangle things directly underneath the resistor. Can u tell me the name of the tiny black rectangle things normally on the bottom of boards and the markings beside them normally start with a R? So now its gona take me tommorrow to figure out if i should just buy a power board for $50 and hope that would solve the original problem and the one I created? Any suggestions is greatly appreciated lesson learned on testing transistors in a tight spot

you might as well upload the other shopjimmy image of the underside but images of your board would be handy for BUDM. Save the SJ image, open in paint and edit to mark the spot of the "thing"
The other problem now is , was it the PSu faulty or PSU good and LED strips faulty.

Found this

https://www.badcaps.net/forum/showth...light=ELEFW502

[budm]

Re: Seiki 50 inch has no back light

There was no follow-up on that thread either so I did not get very far on that one.

[budm]

Re: Seiki 50 inch has no back light

There was no follow-up on that thread either so I did not get very far on that one.

[tw2005]

Re: Seiki 50 inch has no back light

I think the server just freaked out and gave you a double post LOL.

True but johnboy @ post #5 mentioned his tv had bad LED strip. Since he said he had the same symptom as OP of blue light no pic,no sound assuming neither shone light to see if an image was present I can see this ending up with a replacement PSU and same fault. Just a gut feeling though.

I'm expecting same internals just a badge job

[budm]

Re: Seiki 50 inch has no back light

Sure did.
I will not be surprised that he will have bad LEDs.

[bluedawg]

Re: Seiki 50 inch has no back light

I promise to get u guys a good picture of bottom of PSu , please understand I am still learning the Abbreviation so I am assuming PSU would be Power SUpply Unit. I do know more after studying board than I did before I shorted part of it out. At connection 1 for led strip I had power i think 260v on one pin but when I tested the other 4 cnnectors beside itI didnot have any voltage. This was true before I shorted out resistor that cracked and burnt little resistor underneath it. I will get the requested info and post it later today. Thank you all again .

[bluedawg]

Re: Seiki 50 inch has no back light

ok heres the the exact board that I have and the red box shows the resistor on top that is blackened and cracked. The yellow box shows the resistor I have no idea if its bad or how to identify it for replacement . it did make a black mark on area underneath the board .the resistor on top is brown then black then silver then gold band . I also can not find this resistor to replace it online, i dont know the watts i know the ohms is 0.1.

[budm]

Re: Seiki 50 inch has no back light

You need to check the resistance between the Source and Drain pin of the PFC Power MOSFET Q2 to see if is shorted out (very low Ohm), that Source resistor (0.10 Ohm) that went out for a reason, I have no idea why they put a small SMD resistor in parallel with the Source resistor, no need for that at all.

[bluedawg]

Re: Seiki 50 inch has no back light

I got a new powerboard and put it in. I have 4 volts dc going to BL on power board from motherboard. When i test led connector 1 red wire it has 270 volts and the white wire has 170 . Then on led connector 2 the red has 88 volts and 0 on white then connector 3,4,5 all have 0 on both red and white wire. Obviously im lost here on why the backlights will not come on . Is there any way to put power to leds just to see if they will come on . I can not find a inverter or a led driver. Thank u advance im really baffeled.

[bluedawg]

Re: Seiki 50 inch has no back light

I got a new powerboard and put it in. I have 4 volts dc going to BL on power board from motherboard. When i test led connector 1 red wire it has 270 volts and the white wire has 170 . Then on led connector 2 the red has 88 volts and 0 on white then connector 3,4,5 all have 0 on both red and white wire. Obviously im lost here on why the backlights will not come on . Is there any way to put power to leds just to see if they will come on . I can not find a inverter or a led driver. Thank you in advance im really baffeled.

[bluedawg]

Re: Seiki 50 inch has no back light

Mr Budm Now that I replaced power board I can tell you I have 5volts dc going to BL pin on powerboard and I have power on red and white wire connector 1 for back lights and power on red only wire on conector 2 for BL and no power on other 3 connectors . I think it was like 240 on 1st connector red wire and 120 on white wire 1st connector and 88 on red wire on 2nd connector. Hope this helps you help me.