Samsung PN58C8000 No picture, repair help please


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Samsung PN58C8000 No picture, repair help please

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Curtis_H
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Jul 10, 2015, 1:59 PM

Post #1 of 5 (3290 views)
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Samsung PN58C8000 No picture, repair help please	Can't Post

Samsung PN58C8000 No picture, please help
I have a Samsung Plasma PN58C8000YFXZA, love it, great picture, until it went blank.

T.V. will turn on, makes the sound when power on and power off, BUT no picture, total black, when turning it on, the screen flashes very fast and NOT the entire screen a white flash then goes away.

Watched a guy’s video on YouTube (Tampatec) on how to use a multi-meter to troubleshoot power issues, with the SMPS (power-board) and this is what I came up with and have done.

the internal tag says this

Va=55 | Vsc=-200 | Vs=209 | Ve=90

Tested the VS-TP = 13.6 | Va-TP= 1.2

Powerboard to Y-Main (CN804), tested both sides
Vs=13.6 | Vs=13.6 | Va=1.2 | Va=1.2

PowerBoard to X-Main (CN803), tested both sides
Vs=13.6 | Vs=13.6

Logic Board (CN802) When turned on LED2001, blinks green, LED2000 remains off
D5.3V (Far Left) 5.22
D5.3V (Second Right) 5.22

Because all of the points tested were off from the internal tag, I figured the powerboard (SMPS) is bad, went to ShopJimmy and ordered a powerboard (BN44-00334A), Installed the board and retested.

Results of the new powerboard installed

CN804
Vs=14.8, both 1&2
Va=1.6 & 1.7

CN803
Vs= 14.9, both

CN802
D5.3v=5.1, both
PS_ON= 0
Vs_ON=0

CN801
(1)
15v=15.1
15v=15.1
15v=15.1
GND
GND
5.3v=5.1
5.3v=5.1
18v=17.5
18v=17.6

(2)
N/C
N/C
GND
GND
GND
GND
5.3v=5.1
STD5v=5.1
PS_ON

Y-Main board
VscON=3.9
Vsch=.4
Fuse=14.8

X-Main board
C4108=14.5
Fuse=14.85

SMPS (powerboard)
Fuses
F801s=1.0
F802s=121.7

Tested the power coming in and its 120.5

When T.V. is turned off, BUT still plugged into wall outlet, I have tested these points.

CN801
PS_ON=3.27
STD5v=5.25

CN802
Vs_ON=.06
PS_ON= 3.27

Thought I got a bad SMPS (power-board), which I know being in Networks/IT field that just because its new, doesn't mean its always good, that they fail as well new, which I've seen computer parts bad, new.

Sent off for a RMA on the power board and ShopJimmy.com sent another one, PLUS I purchased a Y-Main and an X-main board as well.

!!!!!Installed all three and still no picture, but still has the sound when turning on and off.!!!!!!

Can anyone help in trying to help me further troubleshoot this TV, I want to fix it and keep it as its (I think) an awesome Plasma TV.

Thanks,

Curtis
Mad

omendata
New User

Jul 26, 2015, 7:58 PM

Post #2 of 5 (3225 views)
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Re: [Curtis_H] Samsung PN58C8000 No picture, repair help please [In reply to]	Can't Post

Sahme no one has replied - I am in exactly the same situation and am sure its the t-con board.

Try changing the t-con and just re-advertise the parts you obught on ebay to get your money back.

Im also cisco network engineer and server guy but have a lot of electrical experience but im not specifically plasma televisions - like computeres its all board swapping these days even the electrical repair shops dont do soldering and proper testing with an oscilloscope they just swapout boards until the problem is solved.

Nightmare without my 50 incher having to use my 24 inch monitor for the moment its been two weeks and still havent fixed it.

Ordering a t-con board tonight and then its a new tv for me!

Repair man
Enthusiast

Jul 27, 2015, 4:36 AM

Post #3 of 5 (3215 views)
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Re: [Curtis_H] Samsung PN58C8000 No picture, repair help please [In reply to]	Can't Post

This symptom is usually caused by a bad upper or lower buffer board. (in your set they may call them the top Y scan board & lower Y scan board)

If you disconnect & remove one of these boards at a time (leaving one board in the set at a time) & try the set you may get the top half of the screen or the bottom half to light up, whichever half lights up that board is likely still good.

Disconnect the power to the TV before removing these boards. Be very careful with the ribbons going to the panel; they are factory bonded to the panel & can't be changed so if you damage one the TV is headed for the recycle pile.

There will be clips that clamp the ribbon cable to the boards, study them & research them to see how they are released before removing the ribbons.

If you type your TV model number into shopjimmy.com you'll see the boards (& prices if they have them in stock)

If you are not a tech it's much simpler for you to just change the board but for those of us techs that still like to get in there & change parts on the boards, it's often just a bad / shorted little brown surface mount cap just above or below one of the ribbons & if you use an ohm meter you get a very low ohm reading across one of them (compare them to other similar caps on that board).

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Curtis_H
New User

Jul 27, 2015, 7:28 PM

Post #4 of 5 (3206 views)
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Re: [omendata] Samsung PN58C8000 No picture, repair help please [In reply to]	Can't Post

omendata;

Thanks for the reply. First question is whats a t-con board? Non of the boards in my set are called that, can you tell me which board that is?

Thanks,

Curtis

omendata
New User

Jul 27, 2015, 10:03 PM

Post #5 of 5 (3200 views)
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Re: [Curtis_H] Samsung PN58C8000 No picture, repair help please [In reply to]	Can't Post

Listen to repair man he is correct you need to do some testing first.

I didnt read all of your post and jumped in because its sounds similar to mine but i have a black screen nothing no flashes or picture at all - i missed that on your post - sorry - the sound with no vision is a tricky one to troubleshoot but here is what i have learned over the last two weeks of study.

The most common fault for this is the y-sustain and y-buffer boards - remove the buffer boards as repairman has said one by one.

You can also take them off and do a continuity test between the vs voltage test points on the left side of the board and run your meter down all the connection to the ribbon cables on the plasma screen - if you get a beep in other words a connection the chip has shorted - you can replace these chips if you want but its a tricky and pain in the ass job especially if you have to re-glue them - always make sure you reglue but with my tv they only cost £20 so not worthwhile fixing unless you want to learn a bit.

It could be z-sustain board - from what i gather this board going wrong is the one culprit for weird colours , sparklies, picture distortion and red tinges to the picture but it doesnt usually go first.

In my case i tested everything and removed the boards and tested all the components as well as i could until i am now down to the t-con - guy on ebay is actually coming round with it tomorrow so we shall see if my diagnosis is correct or if i am talking out of my arse as usual!
lol

Good luck

Omen

T-CON OR TIMING CONTROL is the logic board that ties all the system together to provide the picture - the main board usually has all the hdmi connectors on it - ysus is usually on the left of the back attached to the y-buffers and z-sus on the right.

PS. Nice one repair man I read Jestine Yongs newsletter every week - he is a genius!!!

(This post was edited by omendata on Jul 27, 2015, 10:12 PM)

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