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Experience:  30 Years experience. Authorized Warranty servicer.
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my Samsung Plasma TV PN42C450B1D will not turn on. Power ready

Resolved Question:

my Samsung Plasma TV PN42C450B1D will not turn on. Power ready light has a rhythmic blinking, but nothing happens. I have unplugged it completely for a day, but nothing has reset. Took the cover off the back and no capacitors are blown. I'm stumped, please advise.
Submitted: 5 years ago.
Category: TV
Expert:  TV Tech1 replied 5 years ago.

You're probably going to need a voltmeter to test the power supply voltages and disconnect a couple plugs to see if the power supply is ok or not.


Do you have one?



Customer: replied 5 years ago.
Expert:  TV Tech1 replied 5 years ago.

Ok, if you have a SEARS near you, they have an inexpensive meter they sell --


That's the best price I've seen on one, and it's a Craftsman.


Right now, since you get only the blinking light, you have either a BAD power supply, or a Bad Ymain or Xmain board --




As you can see, those are the tests we run when we have a Dead TV set.


You can visually check those postage stamp ICs and see if there's a Burn hole on top of them.



Customer: replied 5 years ago.
I have looked over the entire back and no evidence of any burn holes, marks, chars or anything. Also the inside of my TV does not look like the picture shown, but i guess there are differences. The red power lights has a pattern to it, does that matter? It goes 'blink', 'blink', then off for about 3 secs, then repeats the pattern.
Expert:  TV Tech1 replied 5 years ago.

Yeah, I use some "generic" pre-built photos simply because 99% of all TV's have the same layout on the boards, just a little different from model to model.


Samsung TVs don't use fail codes, so the double blink just means the main board is attempting to turn on and it's not getting any of it's startup signals back to it.


In other words, we may be looking at the Ymain....the Xmain....or the power board isn't firing up.


The meter helps us because we can test the power supply to see if it's providing the voltages needed to power up the X and Ymain boards.


I suspect we'll find the Ymain bad, and the power supply is next on that list. Xmains rarely fail, but there is an exception and it's Related to how the Wiriing between the Power supply and X / Y mains are laid out.


Here, let me show you the two wire layouts you find on all Samsungs --




The lowest picture called the Daisy Chained wiring....I've seen the Xmain short on those. The upper picture with they WYE wiring....Ymain is the more common failure on those.


We get to know our TV sets pretty well, so the wiring layout does have a lot to say about where to start troubleshooting.



Customer: replied 5 years ago.
The bottom picture is the back of mine, where things are daisy-chained, and i found my Voltmeter. Plugged in the TV to get power and heard a very faint clicking, like trying to get power, like you said coming from the power supply unit. Where do i test using the voltmeter? and if the power supply is bad, then are they cheap to replace or am i looking at a better investment in a new TV?
Expert:  TV Tech1 replied 5 years ago.

Depends on how much damage you have.


That daisy chain setup...usually the Xmain shorts. If you use your Voltmeter's Continuity beeper test....connect it to the VS pin on the power supply or the Ymain (board on the left). Look right beside the plug for markings on the board that indicate which wire is VS.

Now if your meter beeps indicating a SHORT....unplug the cable that's connected on the Xmain on the right side


I use that test as soon as I get the rear cover off on Daisy Chained units.


VS power is supplied to both the X and Ymain. If the X is shorted it will stop beeping the moment you unplug it.

If the Ymain is shorted it will continue to beep if you connect to the Ymain board. Simply unplug the power supply from the Y main and the shorted board will be totally isolated from all the others.





Customer: replied 5 years ago.
i guess i dont know how to test it, because whatever i do nothing stops the power from flowing. I get a reading at all times. i might just need to take it to someone to see if it's worth fixing. i wish it was as easy as replacing capacitors!
Expert:  TV Tech1 replied 5 years ago.

Power flowing?


You have to remove power from the TV set to do that Beeping continuity test. What meter do you own ? Brand and model?


The Ymain board has the main plug on it that connects to the power supply board.

Right beside the plug....there is a list of what each pin is. Vs GND and probably VA too


We put the Red probe in the Vs pin, the black probe in the GND. IF the continuity beeper Beeeeeeeeeeeeeps, then we disconnect the wire plug that goes from the Ymain over to the Xmain.


Make sure the TV is unplugged for resistance/continuity tests.


Before I even start....I touch the red and black probes together, activate the continuity setting on my meter and make sure I get a beep, then I put them on the VS and GND pins.



Customer: replied 5 years ago.
ok, disconnected the power, unplugged it completely. Figured out how to test meter for continuity test and it works like you said. Placed red lead into Vs pin and black into GND. I have 2 of each Vs and GND, so i tried all combinations and got no beeping at any time, temporary or complete.
Expert:  TV Tech1 replied 5 years ago.

Ok, no shorts then.


Plug the TV in....leave the meter connected to Vs and Gnd. Switch over to the DC voltage setting....Press the power button while monitoring for DC voltage of about 160 to 200 Volts.


Let's see it it powers up...even a little.


Customer: replied 5 years ago.
nothing happens, even a little, i'm about done with it
Expert:  TV Tech1 replied 5 years ago.

I have a solution....about $125. Costs less than hiring a LOCAL repairman to come to your home to fix it.








If you look closely at your plasma panel, you'll find a Sticker labled Samsung.

If either of those numbers appear on the rear, on that panel, you let me know, Ok?


If we have either of those numbers on your panel, I have an easier Fix for you.



Customer: replied 5 years ago.
Expert:  TV Tech1 replied 5 years ago.



Solution --


Entire thinking required. Good price, just plug and play.


Lay the kit out....swap boards one at a time.....




Thank Goodness your Panel matched those numbers.


If you have any questions, just ask

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Tips are greatly appreciated !


Thank you.



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