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Year-old Samsung 50" Plasma - No Power
My friends found a Samsung PN51F4500A(FXZA) 50-inch plasma TV recently, and I have been tasked with the repair attempt. It was built in September of 2013, so just barely a year old. When I plug it in, the red standby LED turns on. If I press the POWER button (on the remote or on the set) the standby LED goes out...and nothing else happens. It's like the set was unplugged. There is no evidence of physical damage, screen doesn't appear to be cracked, everything inside looks good, nothing burnt/fried, etc. No strange sounds...in fact, no noise at all. There is no info online that I could find about this model having issues. Apparently it's last year's entry-level Samsung plasma TV. No 3D or smart functions.
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Sony Trinitron Fan |
#2
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As for yours, have you checked the power supply voltages? On most plasmas the power will attempt to come up briefly on plug-in. Check your VS and VA from the power supply and make sure you have low voltage (on most Samsungs thats something like +5.3v and +15v). Do you have voltage (briefly) on all of them at plug-in or power button press? If you have VS and VA then you can start to check for VScan / Ve, start looking for X or Y board problems, etc. If you don't even have VS and VA and your low voltages, it's going to lock out immediately so that needs to be fixed first. |
#3
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Yes...check power supply voltages first...and look for bulged caps.
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Let me live in the house beside the road and be a friend to man. |
#4
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YamahaFreak: I also forgot to mention, check the obvious, like fuses... The main AC input fuse must be good to be getting the red light but there are usually at least a couple small surface mount ones on the logic board. Speaking of the logic board, Samsungs usually have a green LED on them. What is yours doing? It should sit there and flash with a period of about once per second if everything is normal. The problem with this one here turned out to be a couple of shorted FETs (actually IGBTs, but whatever) on the Y-Main board... I'll have to order some from Digikey tomorrow since they are fancy super-high-current (220A), high speed switchers specifically designed for use in pulse applications in PDPs (like the ERC) so none of the usual stuff I have laying around is going to come even close to surviving in that circuit. |
#5
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Audiokarma |
#6
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A 2013 set could very well have bulged (damaged) caps. Last year I replaced several caps in a 6 month old Sony DVD player.
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Let me live in the house beside the road and be a friend to man. |
#7
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Well, unless there is a cost-effective, non-warranty method of getting a replacement plasma panel, this set's toast. The owner's dog knocked it over and cracked the screen!
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Sony Trinitron Fan |
#8
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Unless you can find the same set with a good panel and ruined boards...Stick a fork in it, it's done.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#9
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Did you ever fix it? If so, check if the boards are worth anything on ebay before it hits the dumpster
Unless it was on when the screen was broken (or was attempted to be turned on after the screen was broken). This will blow the Ysus and/or buffers on some models. |
#10
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No, the set has not been plugged in since it was cracked. That's probably what I'll end up doing - parting it out and trying to sell the boards. *sigh*
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Sony Trinitron Fan |
Audiokarma |
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