HELP Samsung PN58B860 image is dim grainy and there is a dark spot - AVS Forum
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post #1 of 43 Old 02-24-2013, 09:42 PM - Thread Starter
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Correction to the model number, Its a PN58B860 and not a PN64D8000. The box and TV model didnt match up.

Hello everyone,

I came a cross this this plasma on CL and figured why not take a shot of fixing it. Its samsung pn64d8000 PN58B860 it turns on but the image is really, really dim, grainy and there are a few dark spots. The spots are located near the middle\buttom of the screen and near the top right of the screen. When I play a movie; the dark spots at the top right go away. I don't think the screen is broken. Can you guys provide any input on what might be wrong with it or how I can start trouble shooting it? I am hoping that replacing a board or two can fix it.


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post #2 of 43 Old 02-25-2013, 07:46 AM
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It is most likely an X-main failure. I have fixed a PS42B450 and PS42Q97HD with a dim picture and the X-main was an inexpensive part for both. A software update is required after replacing certain boards to reduce the chance of future failures.
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post #3 of 43 Old 02-25-2013, 06:51 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

It is most likely an X-main failure. I have fixed a PS42B450 and PS42Q97HD with a dim picture and the X-main was an inexpensive part for both. A software update is required after replacing certain boards to reduce the chance of future failures.

TOM669 Thank you for the info. I am a novice at best. From what I have read and seen the board your talking about is located at the top right of the panel. Please correct me if I am wrong. I am adding a left and right picture of the rear panel. I highlighted the board I think the X main board is. Can you please confirm?

LEFT SIDE


RIGHT SIDE



Thanks again.

JM
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post #4 of 43 Old 02-27-2013, 11:29 AM
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That is indeed the X-main.
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post #5 of 43 Old 02-27-2013, 11:36 AM - Thread Starter
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Thank you Tom.. I have ordered the board.
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post #6 of 43 Old 03-05-2013, 03:08 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

It is most likely an X-main failure. I have fixed a PS42B450 and PS42Q97HD with a dim picture and the X-main was an inexpensive part for both. A software update is required after replacing certain boards to reduce the chance of future failures.

Tom,

I got the new board today... After replace it I still have the same issue. Any other suggests for you or anyone else?


Thanks Team.
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post #7 of 43 Old 03-05-2013, 03:08 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

It is most likely an X-main failure. I have fixed a PS42B450 and PS42Q97HD with a dim picture and the X-main was an inexpensive part for both. A software update is required after replacing certain boards to reduce the chance of future failures.

Tom,

I got the new board today... After replace it; I still have the same issue. Any other suggests from you or anyone else?


Thanks Team.
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post #8 of 43 Old 03-06-2013, 10:33 AM
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Check and compare Vs and Ve to the panel sticker. Test points are on the power supply and X-main board.
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post #9 of 43 Old 03-06-2013, 10:43 AM - Thread Starter
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The sticker states Vs = 201 and Ve = 85, I do have an Multimeter but I am sure what setting to set it to.
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post #10 of 43 Old 03-06-2013, 12:12 PM - Thread Starter
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Tom, I was able to figure out the Multimeter,

The sticker on the panel reads :

VS = 201 Tested @ 201 OK
Ve = 85 Can't locate on panel
Va = 55 Tested @ 54 <<<< Test lower by 1.
Vsc = -185 Can't locate on the board.

Also, I left the tv running for a few minutes and found that one heat sink on the Y board is hot to the touch an buzzing .


JM
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post #11 of 43 Old 03-06-2013, 02:10 PM
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Ve is generated on the X-main on this model, I think. Check carefully on the X-main for a test point. And clear pictures will really help.
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post #12 of 43 Old 03-06-2013, 02:44 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

Ve is generated on the X-main on this model, I think. Check carefully on the X-main for a test point. And clear pictures will really help.

I took picture from ebay for the X main board.
I highlighted the test points I did find.

Processed By eBay with ImageMagick, R1.1.1.||B2||T0JKX0lEPTVjYTFhYjFlYTY1YTAyMzgwNTEyMGE1MzM5MjdjMTA1MTI3YTM3MTQyYzRhfHxTRUxMRVJfTkFNRT1uaWdodF9leWVzX3R2fHxPUklHSU5BTF9FQkFZX1FVQUxJVFlfU0NPUkU9NHx8Q1JFQVRJT05fREFURT0zLzYvMTMgMzozOSBQTQ==


Meanwhile I'll continue to look for the Ve.
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post #13 of 43 Old 03-06-2013, 02:54 PM
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Near the top of the board there are some blue capacitors, marked 225K plus other information. What do you measure across these? It should be from 1/3rd to 2/3rd Vs. In addition, there is a fuse inside a fuse holder on the board. You should measure Vs on both ends, do you?
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post #14 of 43 Old 03-06-2013, 03:17 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

Near the top of the board there are some blue capacitors, marked 225K plus other information. What do you measure across these? It should be from 1/3rd to 2/3rd Vs. In addition, there is a fuse inside a fuse holder on the board. You should measure Vs on both ends, do you?

If your talking about these they measured 104

Processed By eBay with ImageMagick, R1.1.1.||B2||T0JKX0lEPTVjYTFhYjFlYTY1YTAyMzgwNTEyMGE1MzM5MjdjMTA1MTI3YTM3MTQyYzRhfHxTRUxMRVJfTkFNRT1uaWdodF9leWVzX3R2fHxPUklHSU5BTF9FQkFZX1FVQUxJVFlfU0NPUkU9NHx8Q1JFQVRJT05fREFURT0zLzYvMTMgMzozOSBQTQ==

VS was measured at that plug (the red highlighted box in the picture) there are two VS prongs both measured 201. I also confirmed the fuse was OK.
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post #15 of 43 Old 03-06-2013, 03:58 PM
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Those were the correct caps, the board appears to work apart from the XE part, so it is either two defective X-mains (unlikely), a control board issue or a Y-main issue.

What's this point labelled (TP_????)
http://i.imgur.com/A1bTaV3.jpg
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post #16 of 43 Old 03-06-2013, 04:11 PM - Thread Starter
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what about the Va testing lower?

Va = 55 Tested @ 54 <<<< Test lower by 1.

Here is a close up a the picture you sent. I dont see any testing points.
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post #17 of 43 Old 03-06-2013, 04:27 PM
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54V is fine, could be attributed to meter inaccuracy, and would not cause underdiffusion as you see.
There is a gold/copper test point marked beginning with "TP" on the right side. What is the rest of the naming?
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post #18 of 43 Old 03-06-2013, 04:46 PM - Thread Starter
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Tom, I took a closer look at that side of the board and found that that is indeed the Ve test point. I tested it and it read 84V ... 1 V less than what is should be.
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post #19 of 43 Old 03-06-2013, 04:57 PM - Thread Starter
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Tom, I also found


Vsc = -185

The multimeter reads 150-165

when I first tested it , it was in the low 50's and when I retested I saw 150-165 .
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post #20 of 43 Old 03-06-2013, 05:30 PM
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Vsc on the Ymain? This could explain your problem.
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post #21 of 43 Old 03-06-2013, 05:56 PM - Thread Starter
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Yes, I found the Vsc on the Y board.

Question: The sticker on the panel stated that the Vsc should be - 185. Does this mean negative 185 or below 185?

so replace the Y board?
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post #22 of 43 Old 03-06-2013, 06:07 PM
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Quote:
Originally Posted by tom669 View Post

It is most likely an X-main failure.

Tom,

Off topic, but thank you for helping us, and welcome to our forum. We've enjoyed your posts and help at badcaps. Thanks again!

That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
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post #23 of 43 Old 03-07-2013, 03:39 AM
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Heh, I'm glad to help.

Is there a Vsc adjustment pot anywhere on the Y-main? Have you tried tweaking this?

Vsc is often measured across a resistor, some test points or relative to ground, dependent on the design. It should be negative though I would highly doubt the supply could reverse its polarity without causing obvious damage e.g. exploding capacitors.
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post #24 of 43 Old 03-07-2013, 08:43 AM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

Heh, I'm glad to help.

Is there a Vsc adjustment pot anywhere on the Y-main? Have you tried tweaking this?

Vsc is often measured across a resistor, some test points or relative to ground, dependent on the design. It should be negative though I would highly doubt the supply could reverse its polarity without causing obvious damage e.g. exploding capacitors.

First off, I second what Tomwil said. THANK YOU EVERY MUCH FOR THE HELP....

I did find 3 adjustment nobs on the Y board. Playing with them, I was able to get rid of the dark spot located at the buttom center. However this did not have any affect on the brightness, color or quality of the image.
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post #25 of 43 Old 03-07-2013, 08:43 AM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

Heh, I'm glad to help.

Is there a Vsc adjustment pot anywhere on the Y-main? Have you tried tweaking this?

Vsc is often measured across a resistor, some test points or relative to ground, dependent on the design. It should be negative though I would highly doubt the supply could reverse its polarity without causing obvious damage e.g. exploding capacitors.

First off, I second what Tomwil said. THANK YOU EVERY MUCH FOR THE HELP....

I did find 3 adjustment nobs on the Y board. Playing with them, I was able to get rid of the dark spot located at the buttom center. However this did not have any affect on the brightness, color or quality of the image.
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post #26 of 43 Old 03-07-2013, 02:11 PM
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Read through this and perform the indicated tests:
http://www.badcaps.net/forum/showpost.php?p=318461&postcount=2
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post #27 of 43 Old 03-07-2013, 04:54 PM - Thread Starter
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Quote:
Originally Posted by tom669 View Post

Read through this and perform the indicated tests:
http://www.badcaps.net/forum/showpost.php?p=318461&postcount=2

Tom,

are you suggesting that the control board is bad vs. the Y board?
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post #28 of 43 Old 03-08-2013, 05:58 AM
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I'm simply asking you to perform the test. I don't know yet for sure what board is bad.
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post #29 of 43 Old 03-08-2013, 10:30 AM - Thread Starter
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Tom,

Per your instrucitons,

Unplug the LVDS cable (see below) I am unclear what cable this is.
I am assuming that the pictures of the board removed from the panel are for easier viewing of the board vs. actually needing to remove it.


JM
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post #30 of 43 Old 03-08-2013, 12:46 PM
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The LVDS cable runs from the main board, which has the video inputs, to the control board, which is the board that has the 3-4 jumper on it.
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