Good day guys, im working on a Samsung LED backlight tv, the problem i changed one blown LED and it ran for couple weeks, when I open it for backlight problem again its the same LED that i changed blown again. i think its not the right voltage, but that is the only ones i have from another strip (i just cut it and wired it to the strip on top).
My question is "is there any resistor i could or any component to add in series or value that could make that particular led up to par with the rest?" I really dont know the voltages but i only see a 3vdc drop across all when measured, also its 4 strip with 7 LEDs each.
My question is "is there any resistor i could or any component to add in series or value that could make that particular led up to par with the rest?" I really dont know the voltages but i only see a 3vdc drop across all when measured, also its 4 strip with 7 LEDs each.
Samsung tv's have gotten to be some of the worst ones out there.
Beginning with flat panel sets, the company went downhill fast.
And at the service shop, the Samsung's were the top set coming through the door for repairs.
We couldn't keep up!.
Plus, their customer service was crap, I've had numerous arguments with those snotnoses.
Lawsuits of all kinds from customers were flowing like water.
As a seasoned old tech, guess what brand I favored for my home....... Panasonic!
We hardly ever saw them come into the shop for repairs!
Beginning with flat panel sets, the company went downhill fast.
And at the service shop, the Samsung's were the top set coming through the door for repairs.
We couldn't keep up!.
Plus, their customer service was crap, I've had numerous arguments with those snotnoses.
Lawsuits of all kinds from customers were flowing like water.
As a seasoned old tech, guess what brand I favored for my home....... Panasonic!
We hardly ever saw them come into the shop for repairs!
can i just put one resistor to the one LED i replace in series for the one strip? it has 7LEDs in series, all the other strips are ok.
Hey wiseoldtech. Your so right with the Samsung TVs. Surprising the Panasonics don't use the good Panasonic caps though. Only a couple of poly SMDs in mine and had Rubycon and Nichicon in PSU, they good but is this normal from them?
Anyway, test the LEDs well till you get the resistance right. I know u don't want unbalanced back lights as even one low can be annoying
Anyway, test the LEDs well till you get the resistance right. I know u don't want unbalanced back lights as even one low can be annoying
Nothing wrong with Nichicon, I use them all the time - highly reliable.
My Panasonic LED set is now 5 years old and never a problem.
And after servicing about every brand for decades, as I said, the Panasonics rarely came in for service.
But I serviced LOTS of Sonys, Samsungs, LG's, Philips... and those other junk sets like Westinghouse, Emerson, Polaroid, Sansui, etc.
Back in the "picture tube era" aka CRT, the Sony Trinitron sets were made quite well, and easy enough to service back then.
However, the later Sony CRT sets were made with less quality - some sets literally "fell apart" due to the plastic used in the cabinets - stress cracks erupted from the heavy picture tubes, with some actually caving in!
But even back then, the Panasonic CRT sets outlasted many other brands.
My best friend bought a Panasonic "Prism" deluxe TV in 1988 which lasted without a problem for 19 years before it finally blew the power supply.
My friend got his money's worth from that nice set, and naturally, with my suggestion, then bought a Pana Viera LCD set, which he still has, and and more recently a Viera LED set.
I've suggested Panasonic to all my friends, and they've all had good luck with them.
Working in the shop for many years allowed me to watch, and follow the quality of sets and how well they held up.
On top of my refrigerator is a 10 inch Panasonic CRT set from 1989, and it's still running perfectly.
NOTE: to any USA customers - Panasonic unfortunately stopped selling their TV's in the USA a few years ago, for the time being, however when they might resume sales is in question.
To answer your question without any specifics...
It appears all the LEDs are in parallel. If so then yes you could put a resistor on just the one replacement LED. The only way to know what the value should be is to know the voltage applied to the strip, the forward voltage and the current of the LED you're replacing, etc., BUT, it doesn't seem as that's an option. It's only going to be a guess and the larger you go the dimmer it will be. Since it's burning up the replacement LED I would start out with maybe a 100R or so and see what happens. If it burns again then double it. You can use any style resistor that will fit. You may want to use at least a 1/4 watt just to be safe.
It's just a guess without all the specifics. Good luck!
TJ
It appears all the LEDs are in parallel. If so then yes you could put a resistor on just the one replacement LED. The only way to know what the value should be is to know the voltage applied to the strip, the forward voltage and the current of the LED you're replacing, etc., BUT, it doesn't seem as that's an option. It's only going to be a guess and the larger you go the dimmer it will be. Since it's burning up the replacement LED I would start out with maybe a 100R or so and see what happens. If it burns again then double it. You can use any style resistor that will fit. You may want to use at least a 1/4 watt just to be safe.
It's just a guess without all the specifics. Good luck!
TJ
For what it's worth, in a Samsung TV that I helped a friend scrap, all the LEDs were wired in series; the power supply board silkscreen includes the drive voltage and current:
194V 430 mA
6 strips of 9 SMD LED
194/54=3.6 volts (all LEDs in series)
(The TV had been working just fine, but it seems that rubber bungee cord is not the best choice for a wall mount.)
194V 430 mA
6 strips of 9 SMD LED
194/54=3.6 volts (all LEDs in series)
(The TV had been working just fine, but it seems that rubber bungee cord is not the best choice for a wall mount.)
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