Flat screen Power supply repair

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pishta

I know I'm right....
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Not automotive related, but some shops and most homes have them nowadays and they all run on a power supply that most likely has .50 capacitors populating the boards. My old Samsung 46" started to randomly turn on off and on. click.....click....click...or in other situations you'll have a flashing red power light on the front of the TV an no picture. Pop the back and open the power supply cage. Youll (hopefully) find a few of these capacitors are swollen at their ends causing the 'vents' to buckle or even open. These are the bad one and need to be replaced. They are polarized so the stripe is the - on these and must follow the markings on the board, just replace as you took out. Voltage is not critical as long as you go over what is spec'd, never under. And of course, the capacitance value must be followed as its easy enough to buy the right value but sometimes the voltage is not stocked. Solder in the new ones and your back in biz IF these were the problem. Mine is back to working status with caps I scrapped from other devices. Computer power supplies have quite a few in them. I also have a Capacitance tester so I'm a little spoiled but you can usually tell: if they are swollen they are bad. Its often cheap enough to just buy all new caps in a kit for $15 on Ebay (by model number) or hit the electronics supply with a list. 2 cap next to each other are blown and one JP822 has let the smoke out. Good luck. These are about .30 a piece. Saved a $700 TV in its day.
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I bought this TV 5 years ago for $30 as it "didnt work" but I had an idea what was wrong with it. These 2 caps (as well as the other 10) were replaced by me 5 years ago! These are 1000UF 25V 85C so I replaced them this time with 1000UF 35V 105C parts that were slightly bigger but still fit the footprints. The 85-105C is the temperature rating. Not sure if they get hot (no signs of charring) but that is what I had on hand. The clicking is the standby voltage drifting up and down crossing the voltage threshhold of the power relay, should have been a stable voltage until you hit the power button, then it rises to trip the ON circuits. There should be voltage values printed on the PCB at one of the ribbon cables if your curious and would be a good place to check if the caps look good.
 
My 55" Visio crapped out, so I bought a new one ( I wanted a 65" anyway). Started looking into fixing the 55" to possibly re-purpose in the family room and my model had two boards connected by a header connector. Well the solder joints on the male side would go to hell. So I popped off the board, took it to work and re-soldered it and "Robert's your Father" it works great! Boys were watching uTtube on it yesterday while the wife and I watch Expedition Unknown on the 65".

I'm not an electronics guy either, I don't believe in that witchcraft black magic. I'll take a MIG over a soldering iron any day.
 
I replaced the whole ps board in our 46 in samsung for $35 no soldering required unplug remove replace plugin works great
 
I had a 48 inch Samsung doing the same thing, google model number, found out there was a class action law suit against Samsung. Called the phone number and they sent out a local tv repair to fix power supply.
 
Biggest problem for me is finding ANY documentation on any of this "new ****"
 
LOL I was talking about circuit diagrams, AKA schematics of the TV

Hell at work I must use lead free solder. THAT was a learning experience. It is much higher temp than lead based, and you can really melt stuff if you aren't careful. My surface mount talent has increased even in my old age. I still can't change the microprocessor in the drive module, to. They are pretty "dense."

A little it of what I do. These are cropped shots of the main drive modules for the wheelchairs we build

Below are a couple of caps and a resistor. I can replace these easily, that is .031" solder for size comparison

Module2acs.JPG


Below is the microprocessor, again with .031" solder. I cannot reliably replace these

Module1bcs.JPG


Below, you can see that .031" solder is WAY bigger than TWO of the micro leads. We have smaller solder at work, I believe it's .010"

Module1acs.JPG

Below, another shot. The big buss bar at the left I install, using a huge 250W American Beauty "old school" iron. Likewise the terminals coming up from bottom
module2cs.JPG


module1cs.JPG
 
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I had a nice Sony flat screen that worked good before a couple hour car trip home. Lost video, but still had audio. Poked around in it for awhile, couldn’t find anything. No documentation available. Then it got a visit from Mr Sawzall. Now it resides In that great tv land in the sky.....
 
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