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Crumbtrail TV Forums: TV Equipment: Plasma TV Forum:
Samsung Plasma TV PN51E450A1F Lightning Damage

 

 


cookch1
New User

Oct 26, 2016, 3:07 PM

Post #1 of 14 (11227 views)
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Samsung Plasma TV PN51E450A1F Lightning Damage Can't Post

I have a 51 inch Samsung plasma TV model number PN51E450A1F that has been damaged by lightning. When I plug it in all that happens is the screen lights up then becomes dim and then goes black. There are no blinking lights on the front and no clicking or any other noises. The power button on the bottom does not seem to do anything. I am trying to diagnose what board(s) could be bad. I have tested all the Vs, Va, Vsc and Ve contacts on the boards that have them and they all match what is on the sticker. The logic board has a blinking green light about 1 time per second. When I probe the PS_ON wire on the connector leaving the power supply board it shows 0.89V...I'm not sure what that value should be. All other voltages shown on the board connectors match what I probe. Any help is appreciated!



jts1957
Veteran


Oct 26, 2016, 6:21 PM

Post #2 of 14 (11226 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post


Quote
When I probe the PS_ON wire on the connector leaving the power supply board it shows 0.89V


Does it change to another value when the POWER button is pressed? And then back to the original value when the POWER button is pressed a second time?

IF power board IS putting out all voltages, especially Stand-by voltage and PS_ON is NOT toggling, then the Main board would jump to the top of the suspect list.

http://imgur.com/a/nYiem


-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Oct 26, 2016, 6:28 PM)


cookch1
New User

Oct 26, 2016, 6:32 PM

Post #3 of 14 (11220 views)
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Re: [jts1957] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Thanks for the reply. I am assuming that stand-by voltage is labeled as Vs? I did probe the ps_on voltage while pressing the power button on the TV and the voltage reading did not change.


jts1957
Veteran


Oct 26, 2016, 6:53 PM

Post #4 of 14 (11219 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

CN801 Pin #2 "STBY"

http://imgur.com/a/MWT9U


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Location: Far, Far Away


cookch1
New User

Oct 26, 2016, 8:53 PM

Post #5 of 14 (11215 views)
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Re: [jts1957] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Ah, I see it on the board! I was looking all over for CN801 stamped on the board. What should the voltage be on pin #2 (Standby)? Is that the Vs value on the sticker? I only probed the ones that had voltages stamped beside them and that one didn't have a voltage stamped on it. Sorry if I have dumb questions, I am a novice! Thanks again!


jts1957
Veteran


Oct 26, 2016, 8:55 PM

Post #6 of 14 (11210 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

See post #2.

Also fourth box from top in left column of the troubleshooting flowchart


-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Oct 26, 2016, 8:57 PM)


cookch1
New User

Oct 26, 2016, 8:58 PM

Post #7 of 14 (11208 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Sorry, I missed your first diagram (troubleshooting flow chart). I see STANDBY voltage is supposed to be 5V. So, PIN 1 does have a slight voltage but it is less than 1V...does it have to be 0V or is there some tolerance?


jts1957
Veteran


Oct 26, 2016, 9:02 PM

Post #8 of 14 (11207 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

STBY 5 volts all time the set receives AC. 5 volts irregardless of Power button pressing.
PW_ON = 5V / 0V / 5V / 0V - toggles with each press of the Power button.


-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Oct 26, 2016, 9:03 PM)


cookch1
New User

Oct 26, 2016, 9:43 PM

Post #9 of 14 (11202 views)
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Re: [jts1957] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

So, PS_ON(PIN 1) has voltage of approximately 0.89V...is that a problem? Do you still suspect the main board?


jts1957
Veteran


Oct 26, 2016, 9:51 PM

Post #10 of 14 (11199 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Let's approach this from another angle.

Does that pin go up on a press of Power button?
Does that pin go down on the next press of Power button?
OR
Does that pin remain approx. 0.89V irregardless of how many times the Power button is pressed?

IF it is NOT changing with EVERY press of Power button, I'd suspect the Main board.


-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Oct 26, 2016, 9:53 PM)


cookch1
New User

Oct 26, 2016, 9:57 PM

Post #11 of 14 (11195 views)
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Re: [jts1957] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

The voltage on PIN 1 does not change when the power button is pressed. I'm gonna order a main board and see if that fixes it. I'll update when I'm done. Thanks for the insight!


cookch1
New User

Nov 3, 2016, 3:11 AM

Post #12 of 14 (11120 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Got a used main board off EBay for $15, installed it and everything works!


jts1957
Veteran


Nov 3, 2016, 4:59 AM

Post #13 of 14 (11116 views)
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Re: [cookch1] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

For now. Wink


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Location: Far, Far Away


rrobor
Veteran

Nov 14, 2016, 11:09 AM

Post #14 of 14 (10641 views)
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Re: [jts1957] Samsung Plasma TV PN51E450A1F Lightning Damage [In reply to] Can't Post

Yup fraid so. But you never know, the guy may be lucky.
not usual though. At $15, worth the bet.

 
 
 


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