how often are bad capacitors responsible for LED monitor failures?

[xeos]

I've had great luck repairing computer monitors and LCDs made in the 2000s when CFL backlights were the only option. In most cases it was easy to see leaking capacitors on the power supply and replace them, and at least 5 out of 6 displays were fixed successfully this way. I've recently taken apart a couple LED backlit TVs, expecting to continue my success, only to find capacitors that look completely fine. Is it still worth trying replacing them? Or are LED TVs, because of their lower power demands, no longer killing power supplies (or maybe caps have gotten a lot better)?

sorry if this is answered elsewhere. I've read the getting started guides.

[nomoresonys]

Re: how often are bad capacitors responsible for LED monitor failures?

Since the average lifespan of an electrolytic cap is 10 years, any that age or older are always suspect, check out the sneaky bad caps that NorCal found here:

https://www.youtube.com/watch?v=3S-3J-FySzc

[xeos]

Re: how often are bad capacitors responsible for LED monitor failures?

It depends a lot on the brand and how hard they are driven too. my real question is how common is it for a modern TV to be taken down by a bad cap? I know how to fix those and so I've eagerly taken dead TVs in the past and fixed them most of the time. But the last two that I picked up were LED TVs with no sign of bad caps and much less hope that I can fix them. Fluke, or the new lay of the land?

[jjanssen7]

Re: how often are bad capacitors responsible for LED monitor failures?

In my experience, capacitors still are sometimes (but not often) the problem as they are somewhat more vulnerable to heat and age stress issues than other components. However, I've gone from about 95% bad cap repairs to about 5% or less of what I repair being due to bad caps. I also don't repair "off brands" as they have little to no resale value where I live.

There seems to have been an epidemic that included items manufactured up until about 2012-2013, an epidemic that has fallen off significantly from there. (see note below). That's also in the 10 year window as mentioned by a previous poster, so I do expect to see a few bad cap issues remain.

Anything older than 2015 is hardly worth repairing for me. Too great of a risk of the development of other problems (BGA faults, cold solder joint failure, other component failure) after resale and low resale values for 5-6 year old tvs.

LED failure is the new epidemic. I'd say over 60% of what I'm able to repair is due to LED failure. That's where I start looking these days.

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Note from Wikipedia: A 2003 article in The Independent claimed that the cause of the faulty capacitors was in fact due to a mis-copied formula. In 2001, a scientist working in the Rubycon Corporation in Japan stole a mis-copied formula for capacitors' electrolytes. He then took the faulty formula to the Luminous Town Electric company in China, where he had previously been employed. In the same year, the scientist's staff left China, stealing again the mis-copied formula and moving to Taiwan, where they would have created their own company, producing capacitors and propagating even more of this faulty formula of capacitor electrolytes.

[nomoresonys]

Re: how often are bad capacitors responsible for LED monitor failures?

Like everyone says, the biggest problem with led lit tvs is they are set up to fail, because the leds are driven too hard, it must be on purpose by the makers so they can "sell more tvs"?? So that's mostly the problem with led lit tvs not the caps near as much.

[xeos]

Re: how often are bad capacitors responsible for LED monitor failures?

Good to know, thanks. Funny, LEDs were supposed to last forever compared to CFLs.

I'm trying to fix a Samsung LED at the moment - I've read elsewhere that bad LEDs can fry the power supply, so even if my power supply tests bad I shouldn't try fixing it until I can verify the LEDs?

[jjanssen7]

Re: how often are bad capacitors responsible for LED monitor failures?

I think this is from Badcaps.net:


What is the legend behind the badcaps? Well, the rather dubious story behind this problem is that a scientist working for the Japanese company Rubycon left the company and began working for Luminous Town Electric in China. He developed a copy of the Rubycon P-50 water based electrolyte which is what they use in the Low-ESR caps that are present on all motherboards. Unfortunately his staff left and stole his electrolyte formula. They started producing tons of the electrolyte and supplied many Taiwanese capacitor manufacturers. Unfortunately the formula was incomplete and did not contain the additives that prevent electrolysis from occurring inside the capacitors and releasing hydrogen gas which bursts the capacitor at the vents at the top or at the bottom of the capacitor can.

[jjanssen7]

Re: how often are bad capacitors responsible for LED monitor failures?

Good to know, thanks. Funny, LEDs were supposed to last forever compared to CFLs.

I'm trying to fix a Samsung LED at the moment - I've read elsewhere that bad LEDs can fry the power supply, so even if my power supply tests bad I shouldn't try fixing it until I can verify the LEDs?

Yes, especially with certain Samsung Tvs. I can think of a few 55" & 58" models right off the top.

Better to post a new topic asking a question about your specific model at this point...

[nomoresonys]

Re: how often are bad capacitors responsible for LED monitor failures?

Sometimes it's not the tv twice a year it's just this:

https://blog.rittercommunications.co...nal-scrambling

[Davi.p]

Re: how often are bad capacitors responsible for LED monitor failures?

The LCD displays no more fails for bad caps, and this is the fact that i daily see... so it's obvious that caps improved in quality and the less heat helps.. by the way i can also think that those were the first stage of the so called programmed obsolescence, that method is become not useful due to large usage of people self repairing them, now the obsolescence methods are more sophisticated..

[nomoresonys]

Re: how often are bad capacitors responsible for LED monitor failures?

"now the obsolescence methods are more sophisticated.." Care to elaborate, what other methods have you seen then?

[Davi.p]

Re: how often are bad capacitors responsible for LED monitor failures?

i don't interfere with you

[xeos]

Re: how often are bad capacitors responsible for LED monitor failures?

idk I see a lot of tvs thrown away. I don't think self repair is a big concern for them.

[Davi.p]

Re: how often are bad capacitors responsible for LED monitor failures?

You see them now, now tv are much less repairable than 10 years ago, in my town even 5 years ago in the dumpser did found very few flat tv, so the bigger question is not the hobbyst but the repair centers, it's a job that has no future for low cost devices..

[xeos]

Re: how often are bad capacitors responsible for LED monitor failures?

Fair point. If they are unrepairable you'd see more tossed, eh? Meanwhile a pretty nice TV costs $200, which is wicked cheap. It's hard to get excited about repairing now that it's getting complex. I still hate the waste, though.