Sammy PN50

[ljintexas]

I have a Samsung PN50 circa 2009 that I picked up. hard starting was the reason it was mothballed. I removed smps and went over(reflowed) all solder joints of items on heatsinks and all major power diodes as I have done this on another PN series plasma with success. Upon startup , I get the jingle then relay clicks then a high pitched squeal with fine vertical lines as in the picture. It will continue to shut down and try to restart on it's own four, five, even six times. Eventually, it will start and deliver awesome picture and sound. Vs is good as is Ve, I cannot find test pad for Va, Vsc is not good. Found test pad on Y main and measured -50 to -53 volts, (even when running with good picture) should be -196 according to label on pdp. Once it starts, it will run for as long as I want to run it. Turn it off and as long as I restart it within 60 to 90 seconds, starts right back up..waited 5 minutes, back to the squeal with the lines. Is Vsc generated on the smps?

[ljintexas]

Re: Sammy PN50

Kind of a dumb question...wasn't it..Vs and ground are sent from smps to Y main. Vsc must be developed on the Y main. Thus a measure of the performance of the Y main.

[ReeceyBurger123]

Re: Sammy PN50

Ahh well, let me state the following:

Psu Vs rails wont cause lines out on the Pdp.
Failed Ymain or Xmain wont cause lines out on the Pdp

What could cause this is either the mainboard or control board which is located to the left of the mainboard.

[ReeceyBurger123]

Re: Sammy PN50

You could try heating the Mainboard with a hair drier to see if helps the issue looks like a Mainboard issue to me.

[ljintexas]

Re: Sammy PN50

I will give that a try Reecey!

[ljintexas]

Re: Sammy PN50

Well shazam! Heated main board and she came right on..

[ReeceyBurger123]

Re: Sammy PN50

Ahh nice one Did you replace all the Smd caps ?

[ljintexas]

Re: Sammy PN50

Turns out this is a known issue...Audio chip on front and one 8 leg IC and smd cap on back of board is causing it. I can ship it off for repair for $40 including shipping....I do not have a hot air station so it looks like I will be sending it off.

[ReeceyBurger123]

Re: Sammy PN50

It very well is that Ic regulates 3.3v for the Cpu when that messes up it causes alot of issues they become heat sensitive when they fail.. Was just about to say order that and all should be good