Samsung UE48JU6400W - back light on, sound on, sometimes picture.
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
Thanks for the info / clarification. you might have to look under the shield / cover to see if there is a third led.
The leds are associated with voltages on the board and as you have potentially figured, the flashing one is associated with 12v (panel driving) while the solid is associated with 3.3 (logic). Your measurements appear to indicate a potential "excessive load" on the 12v which causes it to "droop".
I have to re-read things, but I think you indicated you had two tcons. Do both respond the same?
My best guess is that you might get lucky with the "tape cutoff" method of stopping certain signal from the tcon to panel. Lots of threads on this method's success. Basically a small piece of tape put on one of the tcon cables (at the tcon) blocks a few of the pins (usually near the one side or the other, 5-10 pins... experiment with positioning).Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
I have to re-read things, but I think you indicated you had two tcons. Do both respond the same?
My best guess is that you might get lucky with the "tape cutoff" method of stopping certain signal from the tcon to panel. Lots of threads on this method's success. Basically a small piece of tape put on one of the tcon cables (at the tcon) blocks a few of the pins (usually near the one side or the other, 5-10 pins... experiment with positioning).
I will try the tape cutoff method.
I will also remove the heatsink on one of the T-Con boards to look for a third LED.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
:-( I guess they used a different design in this board. Of course, don't run the tcon with out the heat sink / shield in place.
Based on my reads, there are a number of voltages (operational towards the panel) that are labeled on the tcon. Things like VcomXX, "VDD", etc. It is likely one of those has an issue which causes excessive draws on the supply 12v. Some people have found checking for shorts around those voltages to find potential issues with the subtending circuit, usually a shorted / failing smd capacitor on the bottom edge driver boards.Last edited by budwich; 06-02-2020, 07:59 AM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
:-( I guess they used a different design in this board. Of course, don't run the tcon with out the heat sink / shield in place.
Based on my reads, there are a number of voltages (operational towards the panel) that are labeled on the tcon. Things like VcomXX, "VDD", etc. It is likely one of those has an issue which causes excessive draws on the supply 12v. Some people have found checking for shorts around those voltages to find potential issues with the subtending circuit, usually a shorted / failing smd capacitor on the bottom edge driver boards.
Probably this evening I will disassemble the set and remove all of the plastic panels around the display to see if there are more things that I can measure.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
Now I am not sure what will happen if i remove it and start the set without that capacitor. Or what is the value of this capacitor if I try to find a replacement.
I need to get some tape and try that first. At least now I know which ribbon cable I should tryLast edited by dronerat; 06-02-2020, 10:11 AM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
pull it first... and try a "quick test". Go from the result. Others have removed bad components on the driver for a bit and then ultimately replaced them. The set should function OK. The "tape cutoff" method could work also.... trace the tracks back to the cable to see which pins are involved to give you an idea of where in the cable you can start with.Last edited by budwich; 06-02-2020, 01:12 PM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
pull it first... and try a "quick test". Go from the result. Others have removed bad components on the driver for a bit and then ultimately replaced them. The set should function OK. The "tape cutoff" method could work also.... trace the tracks back to the cable to see which pins are involved to give you an idea of where in the cable you can start with.
Will get some clear tape to try and cut off some signals.Last edited by dronerat; 06-03-2020, 01:45 AM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
Nevertheless currently I have managed to fix the set using the "tape cutoff" method and it is working for 4 hours straight with occasional checks if it will start after powering off. Not really sure how long it will last, but that will do for now. If it dies again it will be sold for parts.
I want to thank everyone that gave ideas and tips for debugging. You are such a great community.Last edited by dronerat; 06-03-2020, 06:51 AM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
YEP, this right here is why I go to "tape method" first, then work out from there if no joy. Could have had it fixed 2 weeks and 50 posts ago but you learned a lot I'm sure.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
The best clue was in your first post, shop said panel is dead, they didn't lie this time.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
I have had bad experience with electronic repair services both official and not official.
The quote for the repair of this TV by an official service was ridiculous. 400 euro for the panel and about 75-100 euro labor. That is more than what the TV was bought 4 years ago.
Had one JVC which was diagnosed with bad main board. Turned out to be a dead LED strip (one LED was shorted and one was opened) Quote by the repair shop was 70 euro for the board and about 30 euro labor. I got a LED strip for 10 euros and replaced it. (I know I should have replaced all, but this TV was stored to be used as a backup so it's ok).
Had one Panasonic Plasma TV that was diagnosed with shorted panel again. Turned out to be blown transistors on the board that is responsible for the horizontal lines(Not sure how it was called probably P-Board it was long ago). It was even a known issue and repair kits were sold, but the repair kit costs more than a board from a dead TV. Total of repairs - 25 euro. This Panasonic is still working happily in my living room 4 years later.
My girlfriend is joking that we will never have a brand new TV at home.
Also had experience with a ridiculous quote from an official iPhone repair center which was about 200 euros for labor, shipping and replacement of the top speaker, which another repair service managed to do for 15 euro.
So all in all I don't really trust repair services either official or not and try and repair the thing until I am convinced that it is not repairable.
The TV is happily working in my bedroom now. The only difference I have found after I used the tape method is that the left side of the screen needs some time to fully light up when the TV is starting. It starts to light up from the center to the left, and it takes about a second for the screen to come up fully. That is no big deal and if you don't know that it should not do that you will never notice.Last edited by dronerat; 06-04-2020, 01:53 AM.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
Indeed, that is definitely why I put this time, I should have put quotes around it. Some might not agree but I have seen about as many dishonest tv shops as mechanic shops, appliance shops etc. etc.Comment
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Re: Samsung UE48JU6400W - back light on, sound on, sometimes picture.
There isn't much worse than being screwed by a dishonest repairman, then finding out that you were, most suspect but never realize they were, that's why I diy fix it, if I can't then I buy it new. Think it was an episode of 20/20 or similar tv program that exposed dishonest repairmen, was funny how some of them tried to blame the customer once they were caught red handed.Last edited by nomoresonys; 06-04-2020, 05:12 AM.Comment
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