Soniq Smart TV, No Backlight.

[redrooster]

Happy New Year and all that gear fellas! lol This TV Model# E40S12A.AU Will flash the Soniq company logo for a second then the screen goes dark, the sound is still there and the picture is still there too if I shine a torch on the screen. A friend dropped it off for me to fix and he gave me the rundown on what the TV was doing so I tried reflowing the solder joints on the LED driver board first and that worked great for a few days, then it went back to its old ways. There's an RKU SMD transistor Q4 on the LED driver board that's failed by the looks? I measured it in circuit with a DMM diode test, the emitter voltage is lower than the collector voltage. I tried to find the datasheet for it by Googling RKU because that's all the ID it had on it, now I have no idea because there are so many different kinds of RKU transistors? I've done some voltage tests. The white wire(Ex Dim) from the logic board is 3.4v. green (Int Dim) is 3.7v. next #3 (ENA) is 5.2v #4 (Status) is o.ov All the rest of the voltages on that 14 pin connector are 5 x 24v and 5 x grounds. The top left side LED wires are 5.40v vcc. 10.98v LED #1. 10.99v #2. 5.40v vcc. .840v LED #3. .840v LED #4. LED connector on the right hand side is 1.6v #1 & 0.0v for #2,3 & 4. Am I on the right track with that failed RKU transistor? By the way, the transformer or inverter on the board has no voltage at all? I hope you can make out the details on the photo! Q4 is located at the bottom left of the inverter/transformer. I forgot to mention that I've checked all the electro caps on the power supply, they seem OK.

[redrooster]

Re: Soniq Smart TV, No Backlight.

Bumpity Bump!

[maxvalutech]

Re: Soniq Smart TV, No Backlight.

I don't know the model but being a Soniq would check voltages on the 4 regulators on lhs.

[budm]

Re: Soniq Smart TV, No Backlight.

https://www.badcaps.net/forum/attach...4&d=1514874427
Can we get better picture that is in focused? I cannot read the designators, labels, etc.

[redrooster]

Re: Soniq Smart TV, No Backlight.

OK, I've found the problem for sure, its a failed LED backlight. I measured the voltage on the power going to the backlight LEDs from the LED driver board 3 of them read 11volts and one read .895volts. I unclipped the plug from the LED driver board and all the LED driver board readings were 11volts. So, its the number 4 LED backlight ribbon and probably #3 as well. I contacted Soniq to source some LED ribbons for it but they said they don't have any because that model is out of production. Is there some way I can adapt, cut down to size some other LED ribbons or replace the individual failed LEDs? This is all that's wrong with this excellent TV, can anyone help me with this?

[diif]

Re: Soniq Smart TV, No Backlight.

OK, I've found the problem for sure, its a failed LED backlight. I measured the voltage on the power going to the backlight LEDs from the LED driver board 3 of them read 11volts and one read .895volts. I unclipped the plug from the LED driver board and all the LED driver board readings were 11volts. So, its the number 4 LED backlight ribbon and probably #3 as well. I contacted Soniq to source some LED ribbons for it but they said they don't have any because that model is out of production. Is there some way I can adapt, cut down to size some other LED ribbons or replace the individual failed LEDs? This is all that's wrong with this excellent TV, can anyone help me with this?

Yes, individual LEDs can be replaced, or the strip with the failed LED(s).
You need to remove the LCD panel and the polarizing sheets before you have access to the LEDs.

[redrooster]

Re: Soniq Smart TV, No Backlight.

Yes, individual LEDs can be replaced, or the strip with the failed LED(s).
You need to remove the LCD panel and the polarizing sheets before you have access to the LEDs.

Oh, that's great, its good to know I can fix it then. Is there a video showing how to replace the individual LEDs by any chance, or is it a straightforward thing to do? I know how to separate the diffusion sheets etc, to get to the LED ribbons. I've watched a few YouTube videos on how to do that part. Where would I get the identical, individual LEDs to replace these failed ones? I haven't asked Soniq support because they are a joke but I'll ask them anyway, you never know? lol

[vinceroger69]

Re: Soniq Smart TV, No Backlight.

this video will give you a idea on how to replace the leds the main thing is to try and mach the anode and cathode pads to your old leds as you see in this video he uses the wrong led/pad layout (one pad is bigger than the other) but it will give you a idea on how to swap them some people use heating pads to remove the old leds.
https://www.youtube.com/watch?v=Cm6w...YioeUwvS1Uen_s

[redrooster]

Re: Soniq Smart TV, No Backlight.

this video will give you a idea on how to replace the leds the main thing is to try and mach the anode and cathode pads to your old leds as you see in this video he uses the wrong led/pad layout (one pad is bigger than the other) but it will give you a idea on how to swap them some people use heating pads to remove the old leds.
https://www.youtube.com/watch?v=Cm6w...YioeUwvS1Uen_s

Thanks mate! That's a good video you linked me to, he explains things really well. PS Sorry for the late reply, my email alert isn't working for some reason?

[budm]

Re: Soniq Smart TV, No Backlight.

One thing in the Video about putting the replacement LED that has opposite pads from the original so when you mount that LED big pad (which is the substrate for dissipating the heat to the large copper pad of the strip) to the smaller pad instead, your LED will not get proper cooling and will shorten its life.

[redrooster]

Re: Soniq Smart TV, No Backlight.

One thing in the Video about putting the replacement LED that has opposite pads from the original so when you mount that LED big pad (which is the substrate for dissipating the heat to the large copper pad of the strip) to the smaller pad instead, your LED will not get proper cooling and will shorten its life.

What about adding some copper foil to the small pad if my LED polarity turns out to be reversed, that should do the trick.

[budm]

Re: Soniq Smart TV, No Backlight.

You can try and find out how long it will last, if they fail then you just have to open up the panel again, or get the correct LEDs.

[redrooster]

Re: Soniq Smart TV, No Backlight.

You can try and find out how long it will last. if they fail then you just have to open up the panel again, or get the correct LEDs.

I've sent an inquiry to Soniq support asking them about the details of the LEDs they use in Soniq TV Model E40S12A.Au. Like the datasheet, then I can match them correctly. If I can add some extra heatsinking to them all, it shouldn't be a problem again. LEDs will last for years with good heatsinking, so you would think the manufacturer would take steps to fix it? It seems built in obsolescence has become ubiquitous throughout the industry nowadays!

[vinceroger69]

Re: Soniq Smart TV, No Backlight.

once you strip the tv down to the led strips you can measure a old led for physical package size and also maybe able too test a good led so you can tell if the anode pad is the large or the small pad then we should be able help you find replacements leds also on the actual led strip is a part number so that does help too once you know it.

[budm]

Re: Soniq Smart TV, No Backlight.

Soniq (more likely a re-badge) does not make the LCD panel, you need to get the manufacturer and model of the LCD panel to get the matching LED strip, or remove the bad LED to find out which pads are which.
They drive the LEDs at maximum rating with poor thermal management.

[redrooster]

Re: Soniq Smart TV, No Backlight.

once you strip the tv down to the led strips you can measure a old led for physical package size and also maybe able too test a good led so you can tell if the anode pad is the large or the small pad then we should be able help you find replacements leds also on the actual led strip is a part number so that does help too once you know it.

Thanks, mate I'm on to that! (Large and small pads)

[redrooster]

Re: Soniq Smart TV, No Backlight.

Soniq (more likely a re-badge) does not make the LCD panel, you need to get the manufacturer and model of the LCD panel to get the matching LED strip, or remove the bad LED to find out which pads are which.
They drive the LEDs at maximum rating with poor thermal management.

I searched the number on the back chassis and the panel turns out to be a Samsung LTA400HM21 but there are no LED ribbons available so I'm going to have to find some identical LEDs from somewhere. I found that the LEDs are variously described as WLED and edge backlighting LEDs? Where do I source the LEDs from? Any idea?

[budm]

Re: Soniq Smart TV, No Backlight.

You may try contacting comtek in post #12

Panel spec.
http://www.datasheetspdf.com/datasheet/LTA400HM21.html

I believe the LED strip P/N is LJ64-03567A.
You should search around and verify, you may want to open up the panel and see.

Is this your LED driver board?
http://www.shopjimmy.com/samsung-lj9...led-driver.htm

[redrooster]

Re: Soniq Smart TV, No Backlight.

You may try contacting comtek in post #12

Panel spec.
http://www.datasheetspdf.com/datasheet/LTA400HM21.html

I believe the LED strip P/N is LJ64-03567A.
You should search around and verify, you may want to open up the panel and see.

Is this your LED driver board?
http://www.shopjimmy.com/samsung-lj9...led-driver.htm

Yes, thats the right driver board and the right LED strip. Soniq Australia just replied with a photo of the LED strip, now I just have to figure out the right individual LEDs to source and repair the strip? Do any of the numbers on the strip identify the LEDs used by any chance?

[redrooster]

Re: Soniq Smart TV, No Backlight.

Whats going on here? It looks like carpet. lol But I suppose it's for dispersing the light from the lights around the edges of the screen? I checked ebay for 5630 LEDs, that was a number on the strip. I can get a 5-meter strip of 300 5630 LEDs for $5. Would that be right? I haven't dismantled the display because I want to know what I'm in for first and if I can get the right LEDs? P.S. Something went wrong when I tried to upload the other photo, this post disappeared, so I uploaded it to the last post. lol