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Dim Picture on Samsung LN-T4661F after capacitor change

post #1 of 38
5/2/10 at 2:16pm
Thread Starter 
My Samsung LN-T4661 (3yrs old) had been working fine x 3 yrs until 2 days ago, when it blacked out. When I tried to turn it on, it would cycle through clicking, with no picture. The symptom was exactly as shown below in the youtube videos i found.

youtube.com/watch?v=Mm51C_RDIZE
youtube.com/watch?v=BNHHrgX_6cs&feature=related

On the power board (BN44-00168B. vparts4less.com/images/Power%20Supply%20Main%20BN44-00168B.jpg ), there are 6 capacitors in the cold section. 3 are 1000uF 25V, and 3 are 1000uF and 10V. The three rated at 10V were fried. I replaced yesterday with 2 1000uF 35V and 1 1000uF 50V (there were the only ones I could find at Fry's and Radioshack, and as I understand it, you can replace with higher rated capacitors).

Awesomely enough, that fixed the problem of the clicking. THe TV now turns on, but the picture is dim. I have the contrast and brightness up 100% with backlight on 10 and it's still dim. I'm now considering the following:

1) I inadvertently fried one of the capacitors I installed. (I'm not an electrician and had a cheapo soldering iron that didnt get too hot).

2) The firmware needs to updated. I'm praying this might be the problem. I never had to update the firmware since purchase, so I'm skeptical this will work.

3) Somehow, the repair of the power board, made the inverter malfunction? not sure about this. I never opened or touched this part of the TV. Also, if it was malfunctioning, wouldn't the TV just not turn on?

HERE is what I'm planning:

1) I'm gonna buy some more capacitors and try to replace again. I've got nothing to lose here, because if it doesnt work, I;ll buy a new power board.
Should I use 1000uF and 10V as was initially on the board? Or higher voltage. What about a higher capacitance component? what would happen if i used 2200uF, will that deliver more power, and more light to the TV?

2) If 1 doesn't work, then Ill swap out the board.

I AM A TRUE NOOB when if comes to circuit boards and TVs in general, so PLEASE HELP with your insights and suggestions.
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post #2 of 38
5/2/10 at 2:41pm
Try changing your settings for backlighting, brightness, and contrast each at 50% and adjust from there.
If you were running with real low backlighting and realhigh brightness that is probably what caused the power supply overload condition on the capacitors.
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post #3 of 38
5/2/10 at 10:28pm
Voltage rating will not be a factor in performance. Normally the higher voltage will result in a larger unit. I would recommend that you don't increase the capacitance value more than 50% but that is unlikely to change anything. A 15 watt iron is adequate for that type of work. Don't use a battery operated iron.
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post #4 of 38
5/4/10 at 9:39am
Thread Starter 
Thank you both for your replies.

I have tried to up the brightness and the contrast all the way and the picture was still dim.

I went in to the service menu and increased the gain on the brightness to its maximum from 128 to 255. This made the overall picture brighter and allowed me to reset the brightness and contrast on the main menu lower. However, now, I have some backbleeding from the LCD.

It seems to me that the overall power to the LCD is lower since the capacitor change? is that possible.

Walford, if I set the backlight, brightness, and contrast at 50%, how can I change the picture brightness? The only way I figured out was to crank up the brightness gain in the service menu as mentioned above. Again, this worked, but caused some screen backbleed. It's not ideal.

txrose, I read the same thing on this forum. I have repaired the power board and it seems to be working, except the above problem. I have noticed that it powers on slightly slower than before.

Incidentally, I have handshake problems on my PS3 (intermittent, usable, but annoying). I'm thinking of just swapping out the main board and the power board and be done with it.
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post #5 of 38
5/4/10 at 10:07am
I suggested that set them all at 50% and then adjust them to values you like better. I feepl that your number 1 problem is having the backlignting set so low that even maximum brightness and contrast don't help. Remember if there was no backlighting you would see nothing.
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post #6 of 38
5/4/10 at 11:47am
Thread Starter 
walford, I am confused. can u explain in more detail?

Do I go into the main menu, set the backlight, contrast, brightness to 50%, then go into the service menu and set the brightness and contrast there? There is no setting to set the backlight in the service menu.

I did do the above. My problem is that looking at posted calibration settings that most people use, the brightness gain in the service menu on most of these are ~128. If I use that setting, (which it was on), teh picture is dim. I have to jack it up to 255. Although this fixes the dim picture, it causes back bleeding. I don't know why this is the case.

Thanks for taking an interest in my predicament and offering your insights.
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post #7 of 38
5/4/10 at 11:52am
I also replaced some CAPS on the LN-T4661F. It solved my Clicking problem, but now I have the HDMI handshake issue. I read in the Samsung XX61F forum that Samsung was replacing faulty boards to fix the HDMI Handshake issue. I haven't contacted them yet, but do you think I have any shot at getting them to send a new board for a set out of warranty?
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post #8 of 38
5/4/10 at 12:02pm
Just use the normal setting menus and start each of the three functions at a starting value of 50%
Then try adjusting the backlighting up or down about 5% to get the best image then do the same for the brightness and then the same for the contrast. You might go through this cycle a couple of times.
For example for my cable box HDMI connection I have backlight at 57%. Brightness at 53 and Contast at 60.
You need to do this for each connection separatly since your TV will save the settings separatly for each cable connection. The settings for my DVD player connection and for my laptop connection are different but from those above but are not very different.
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post #9 of 38
5/4/10 at 12:05pm
Thread Starter 
My understanding is that the handshake problem is related to the main board, not the power board. I have a 1004 version main board and have the handshake problem. It occurs occasionally, so I can live with it (except when I'm about the knife someone on Call of Duty and it blacks out).

Does anyone have a pdf of the service manual for 4661F?
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post #10 of 38
5/4/10 at 1:03pm
Thanks for the reply and sorry to change direction on the contrast issue. Is there a way to find out what main board I have without opening up the TV? Also I didn't replace all CAPS only 4 with 35V. Could the different voltages be causing the main board to create the HDMI issue that wasn't there before or is it pure coincidence?? Appreciate any advice on what to try.
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post #11 of 38
5/4/10 at 1:49pm
  1. Quote:
    Originally Posted by xdajzax View Post

    ...THe TV now turns on, but the picture is dim. I have the contrast and brightness up 100% with backlight on 10 and it's still dim...

  2. Quote:
    Originally Posted by walford View Post

    Try changing your settings for backlighting, brightness, and contrast each at 50% and adjust from there.
    If you were running with real low backlighting and realhigh brightness that is probably what caused the power supply overload condition on the capacitors.

  3. Quote:
    Originally Posted by xdajzax View Post

    ...I have tried to up the brightness and the contrast all the way and the picture was still dim.

    I went in to the service menu and increased the gain on the brightness to its maximum from 128 to 255. This made the overall picture brighter and allowed me to reset the brightness and contrast on the main menu lower. However, now, I have some backbleeding from the LCD    ...

  4. Quote:
    Originally Posted by walford View Post

    I suggested that set them all at 50% and then adjust them to values you like better. I feepl that your number 1 problem is having the backlignting set so low that even maximum brightness and contrast don't help. Remember if there was no backlighting you would see nothing.

  5. Quote:
    Originally Posted by xdajzax View Post

    walford, I am confused. can u explain in more detail?

    Do I go into the main menu, set the backlight, contrast, brightness to 50%, then go into the service menu and set the brightness and contrast there? There is no setting to set the backlight in the service menu.

    I did do the above. My problem is that looking at posted calibration settings that most people use, the brightness gain in the service menu on most of these are ~128. If I use that setting, (which it was on), teh picture is dim. I have to jack it up to 255. Although this fixes the dim picture, it causes back bleeding. I don't know why this is the case...

  6. Quote:
    Originally Posted by walford View Post

    Just use the normal setting menus and start each of the three functions at a starting value of 50%
    Then try adjusting the backlighting up or down about 5% to get the best image then do the same for the brightness and then the same for the contrast. You might go through this cycle a couple of times    ...


NOTE: In the interest of saving your TV from any further unnecessary damage, I'm going to be BLUNT!

First of all, walford has been *VERY* polite and PATIENT with you. He posted the correct answer in Post #2, but you didn't 'listen'. In the interest of saving your television, I'm going to be more direct.

Second, you cannot just expect to 'read a book' and then go perform open heart surgery on someone. Folks without the proper technical background cannot expect to 'read a forum' and then go perform electronics tasks like a skilled professional. When I determine that a person's skill set isn't up to the task they are attempting, I immediately stop and point it out. Safety is more important than hurting someone's feelings.

So, more BLUNTLY than above, here's your problem (with several examples that may help you 'see the light'):
  • You driving your car, you've got your foot to the floor / accelerator pedal all the way down and you can't go over 10 mph because the fuel filter is clogged, restricting the flow of gasoline to the cylinders no matter how far down you push the accelerator pedal.
    1. Backlight = Fuel Filter
    2. Brightness = Accelerator Pedal
    .
  • You're watering your shrubs, pulling the hose around the yard and suddenly the water output drops to a trickle. The valve at the house is open full, you squeeze the spray attachment with all your might, the water still just dribbles out. You got a KINK 'somewhere' in the hose.
    1. Backlight = KINK
    2. Brightness = Spray Attachment
    .
    You can also REVERSE this hose example:
    .
  • You're washing your car and suddenly the water output drops to a trickle. One of your children decided to 'slightly close' the valve at the house. You squeeze the spray attachment with all your might, the water still just dribbles out.
    1. Backlight = House Valve
    2. Brightness = Spray Attachment
    .
  • Imagine inserting an incandecent 'Lamp Dimmer' control into the circuit for the lamp in a slide or movie projector.
    1. Turn the dimmer down to 10%.
      - What will be the resultant SCREEN IMAGE?
    2. Turn the dimmer up to 100%.
      - What will be the resultant BULB LIFE?
    3. Turn the dimmer down to 50%.
      - -What will be the resultant SCREEN IMAGE *AND* BULB LIFE?
With practically EVERYTHING in life - EXERCISE MODERATION!; *NEVER* operate devices at 100% unless you have to.

I can understand your desire to prolong BACKLIGHT life by running it low. But, since that resulted in the need to run BRIGHTNESS and CONTRAST @ 100%, that should have given you a clue that 'something was wrong'. By continuing to ignore walford and now going into the SERVICE MENU (where you don't belong!) and cranking another setting up from 50% to 100%, you're *REALLY* looking to kill that television.

You've got a CLOGGED FUEL FILTER MAN!!!

Plain-and-simple, here's what you SHOULD do:
  1. Go back into the SERVICE MENU and reset WHATEVER you touched back to what it was (Factory Defaults).
    .
  2. LOWER your BRIGHTNESS and CONTRAST to 50%.
    .
  3. RAISE your BACKLIGHT to 50%.
    .
  4. EVALUATE the picture quality.
    .
  5. If unsatisfactory, adjust ONE control at a time up or down 5% and re-evaluate.
    - If *ANY* control ends up LT 10% or GT 90%, re-think what you've done.
    .
  6. If satisfactory, you're DONE!.
I've been fooling with televisions (i.e. repairing my own) for ~40 years. I took the Bell & Howell course, built my own HeathKit 25" Color TV (Oscilloscope, Nixie-tube DVM), yada, yada, yada...

A SIMPLE method that I picked up along the way for initially setting the controls on a new (CRT) Color TV is as follows:
  1. Set the COLOR, BRIGHTNESS and CONTRAST to 0%.
  2. Set the SHARPNESS to 25%
  3. Set the TINT to 50%
  4. Raise the BRIGHTNESS until the BLACK areas just start to get lighter. "BRIGHTNESS controls BLACK"
  5. Raise the CONTRAST until the WHITE areas get white WITHOUT blooming. "CONTRAST controls WHITE"
  6. Raise the COLOR until the skin tones look natural, not bright.
  7. If the skin tones look 'off' (i.e. green or purple), tweak the TINT.
  8. Sit back and watch a while...
When you ask for help from folks on a public forum, you also have to both 'listen' to their answers *AND* determine if you possess the appropriate skill set to attempt to correct the problem at hand...

Good Luck!
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post #12 of 38
5/4/10 at 8:58pm
Thread Starter 
Thanks for the explanation.

I realize I have a clogged fuel filter. Please do not be belligerent. I'm just looking for help.

Here is what I know:

1) One day my TV was working fine.
2) It suddenly stopped working as I was watching it. No sound, no video.
3) When I tried to turn it on, it would cycle on and off, but no picture, no sound.
4) After reading on this forum, I thought that maybe the capacitors on my power board blew out.

http://dl.dropbox.com/u/64968/IMG_0391.jpg
http://dl.dropbox.com/u/64968/IMG_0401.jpg

5) I replaced the blown capacitors. The TV would then Power on, but the picture was dim. THIS WAS BEFORE I EVEN KNEW THERE WAS SUCH A THING AS A SERVICE MENU.

6) Once I set the service menu back to how it was in default. The picture is too dim, even with the brightness and contrast ALL the way up, which according to you is due to my 'clogged fuel filter'.

What would cause the clogged filter (to beat your analogy to death)?

If I buggered the replacement of the capacitors, wouldn't the board not work at all?
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post #13 of 38
5/4/10 at 9:46pm
Quote:
Originally Posted by xdajzax View Post

Thanks for the explanation...

You're welcome!

Quote:
Originally Posted by xdajzax View Post

...I realize I have a clogged fuel filter. Please do not be belligerent. I'm just looking for help...

I'm *NOT* being belligerent - I'm being LOGICAL and COMPLETE. If you want help, you have to READ, COMPREHEND *AND* FOLLOW the answers you're getting...

Quote:
Originally Posted by xdajzax View Post

...Here is what I know:
---SNIP---
5) I replaced the blown capacitors. The TV would then Power on, but the picture was dim. THIS WAS BEFORE I EVEN KNEW THERE WAS SUCH A THING AS A SERVICE MENU.

6) Once I set the service menu back to how it was in default. The picture is too dim, even with the brightness and contrast ALL the way up, which according to you is due to my 'clogged fuel filter'...

You keep IGNORING the BACKLIGHT setting - did you:
Quote:
Originally Posted by ClearToLand View Post

...Plain-and-simple, here's what you SHOULD do:
  1. Go back into the SERVICE MENU and reset WHATEVER you touched back to what it was (Factory Defaults).
    .
  2. LOWER your BRIGHTNESS and CONTRAST to 50%.
    .
  3. RAISE your BACKLIGHT to 50%.
    .
  4. EVALUATE the picture quality.
    .
  5. If unsatisfactory, adjust ONE control at a time up or down 5% and re-evaluate.
    - If *ANY* control ends up LT 10% or GT 90%, re-think what you've done.
    .
  6. If satisfactory, you're DONE!.

Quote:
Originally Posted by xdajzax View Post

...What would cause the clogged filter (to beat your analogy to death)?

*YOU* - by setting the BACKLIGHT to 10%!

P.S. If you *STILL* haven't adjusted the BACKLIGHT to 50%, you DID *NOT* understand the example analogies (CLOGGED fuel filter; KINKED garden hose). You *SAY* that I'm beating the analogy TO DEATH, but, IMHO, based on your reply, you're *STILL* NOT 'listening' to what's being said...

Once you follow the instructions given initially by walford and then again, in more detail by myself, we can proceed with your 'Troubleshooting'.

Continue to IGNORE the advice being given and eventually your questions will also begin to be IGNORED...
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post #14 of 38
5/4/10 at 10:34pm
Calm down guys! I'm not taking side but there are a few facts I need to point out:

1. "backlight 10" is not 10% with the 4661. That's the maximum (between 1 and 10) one can set in each individual setup (standard, movie, custom) for each individual input.

2. do not try a capacitor other than original capacitance. Not 50%, not even 20%. Use the same capacitance. While a higher voltage capacitor changes the tolerance voltage of the cap (and inevitably increases its physical size), a higher capacitance may totally change the characteristics of the circuit behavior, especially a switching power supply circuit like the one in question.

3. To the original poster, there's an "Energy Saving" option in the "Setup" menu. This is the "master" backlight setting. The 1-10 backlight setting in each individual setup is just to bias the backlight amount base on this. Check your "Energy Saving" setting and try all available options (Off, Low, Medium, High, Auto). The difference should be obvious. If not, it could be a problem of the invertor circuit or bulb or power supply.
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post #15 of 38
5/4/10 at 10:48pm
Thread Starter 
The backlight is set to 10

With the settings in the service menu set back to default settings, the backlight at 10, brightness 100 and contrast ~100, the image is still too dim.


Chris, I have the Energy Savings Off in the user menu.
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post #16 of 38
5/4/10 at 11:31pm
Like I said, have you tried all options for the Energy Saving?

The brightness difference between High and Off should be obvious. If you don't notice much difference on the screen, see if you can notice light level difference through the back slots. If not, you may indeed have a problem with your backlight hardware.
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post #17 of 38
5/4/10 at 11:43pm
Thread Starter 
Yes, I did go through all the options on the energy saving setting. No luck.
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post #18 of 38
5/5/10 at 12:15am
If you're already on "Off", other settings will only dim it further and it'll of course not fix your problem.

What I want to know is by changing from "Off" to "High", does it dim further? While you're at it, try different backlight setting (1 to 10) to see if they make any difference. Again I know it won't fix your problem. I want to know if it indeed changes backlight level.

The reason I ask is that I want to know if some hardware problem is limiting the backlight output in such a way that neither the Energy Saving setting nor the Backlight setting in each individual setup make any difference.
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post #19 of 38
5/5/10 at 6:17am
Thread Starter 
Chris, thanks for taking an interest in my predicament.

When I change from off to low to high on the Energy Saving setting, the backlighting gets progressively dimmer.

When I change the backlight setting, it changes as expected, from dark to light (but still too dim).

Could the impedance on the capacitor I put in the power board, not be suitable for the power board, even though the capacitance matches?
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post #20 of 38
5/5/10 at 7:32am
Quote:
Originally Posted by xdajzax View Post

Chris, thanks for taking an interest in my predicament.

When I change from off to low to high on the Energy Saving setting, the backlighting gets progressively dimmer.

When I change the backlight setting, it changes as expected, from dark to light (but still too dim).

Could the impedance on the capacitor I put in the power board, not be suitable for the power board, even though the capacitance matches?

I think there might be the possibility of a bad solder joint or two...

I'd order better caps, and try again:
Replace 1000uF 10V caps with these - http://search.digikey.com/scripts/Dk...name=P12366-ND
Replace 1000uF 25V caps with these - http://search.digikey.com/scripts/Dk...name=P10876-ND

Check to see if these caps are not too tall for installation though. Enjoy!

I know several people with the same series TV as yours... :S
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post #21 of 38
5/5/10 at 8:10am
Thread Starter 
Thank you. I'll give it a try. Failing that, I'm going to replace the power board.
I'll post a follow up afterwards.
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post #22 of 38
5/5/10 at 10:18am
ChrisChu,
If the 10 setting is 100% backlighting it appears then that the OP may have been running his TV in "torch" mode for the 3 years he has had it.
If this is the case is it possible that the he is nearing the end of life of his backlighting CCFL panel and this is what is causing his loss of brightness and the extra load put on his power supply?
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post #23 of 38
5/5/10 at 1:18pm
Quote:
Originally Posted by xdajzax View Post

...I realize I have a clogged fuel filter...

Nope. Now that CHrisCHu clarified that 10 = 100%, you have a 'bad component'.

Quote:
Originally Posted by xdajzax View Post

...Here is what I know:

1) One day my TV was working fine.
---SNIP---
5) I replaced the blown capacitors. The TV would then Power on, but the picture was dim. THIS WAS BEFORE I EVEN KNEW THERE WAS SUCH A THING AS A SERVICE MENU.

6) Once I set the service menu back to how it was in default. The picture is too dim, even with the brightness and contrast ALL the way up, which according to you is due to my 'clogged fuel filter'...

Remember my earlier statement about 'Moderation'?

Those of us who are not intimately familiar with all brands and models of televisions but are still willing to help out a fellow member went from the understanding of your BACKLIGHT/BRIGHTNESS/CONTRAST settings of 10%/100%/100% to 100%/100%/100%, thanks to CHrisCHu. That changes the diagnosis greatly!
  1. What were the BACKLIGHT/BRIGHTNESS/CONTRAST settings at #1 (...One day my TV was working fine...)?
  2. How long has the BACKLIGHT been at 100% (i.e. 10)?
  3. Over the past 3 years, how many hours per day has the television been on?
  4. Is 'CLICKING from failed capacitors' a common problem on the Samsung LN-T4661F?
  5. Do any other Samsung LN-T4661F owners report BACKLIGHT problems?
  6. Do you own a DVM?

Quote:
Originally Posted by CHrisCHu View Post

...I'm not taking side but there are a few facts I need to point out:

1. "backlight 10" is not 10% with the 4661. That's the maximum (between 1 and 10) one can set in each individual setup (standard, movie, custom) for each individual input
...

This point SHOULD have been made clear by xdajzax in Post #4 after reading walford's reply referencing "...real low backlighting and realhigh brightness..." in Post #2.

Quote:
Originally Posted by xdajzax View Post

...1) I inadvertently fried one of the capacitors I installed. (I'm not an electrician and had a cheapo soldering iron that didnt get too hot).
---SNIP---
Should I use 1000uF and 10V as was initially on the board? Or higher voltage. What about a higher capacitance component? what would happen if i used 2200uF, will that deliver more power, and more light to the TV?
---SNIP---
I AM A TRUE NOOB when if comes to circuit boards and TVs in general, so PLEASE HELP with your insights and suggestions.

From my point-of-view, this indicates low technical experience.

I'm all for folks attempting to save money but not at the expense of safety. Adjusting 'consumer-accessible' controls to 100% is one thing. Replacing components on a circuit board is another entirely. Suggesting changing original component values / specifications WITHOUT a technical background or schematic is now approaching dangerous.
  1. Quote:
    Originally Posted by CHrisCHu View Post

    ...
    ---SNIP---
    3. To the original poster, there's an "Energy Saving" option in the "Setup" menu. This is the "master" backlight setting. The 1-10 backlight setting in each individual setup is just to bias the backlight amount base on this. Check your "Energy Saving" setting and try all available options (Off, Low, Medium, High, Auto). The difference should be obvious. If not, it could be a problem of the invertor circuit or bulb or power supply.

  2. Quote:
    Originally Posted by CHrisCHu View Post

    ...The brightness difference between High and Off should be obvious. If you don't notice much difference on the screen, see if you can notice light level difference through the back slots. If not, you may indeed have a problem with your backlight hardware.

  3. Quote:
    Originally Posted by CHrisCHu View Post

    If you're already on "Off", other settings will only dim it further and it'll of course not fix your problem.

    What I want to know is by changing from "Off" to "High", does it dim further? While you're at it, try different backlight setting (1 to 10) to see if they make any difference. Again I know it won't fix your problem. I want to know if it indeed changes backlight level...

Quote:
Originally Posted by CHrisCHu View Post

...The reason I ask is that I want to know if some hardware problem is limiting the backlight output in such a way that neither the Energy Saving setting nor the Backlight setting in each individual setup make any difference.

Quote:
Originally Posted by xdajzax View Post

...When I change from off to low to high on the Energy Saving setting, the backlighting gets progressively dimmer.

When I change the backlight setting, it changes as expected, from dark to light (but still too dim).

Could the impedance on the capacitor I put in the power board, not be suitable for the power board, even though the capacitance matches?

Quote:
Originally Posted by walford View Post

ChrisChu,
If the 10 setting is 100% backlighting it appears then that the OP may have been running his TV in "torch" mode for the 3 years he has had it.
If this is the case is it possible that the he is nearing the end of life of his backlighting CCFL panel and this is what is causing his loss of brightness and the extra load put on his power supply?

If this were MY television, at this point I would buy myself a SAM's schematic and start checking voltages rather than guess that 'your problem sounds like his problem so change this'...

Good Luck and don't hurt yourself or cause any fires.

You gotta know when to hold 'em and know when to fold 'em
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post #24 of 38
5/5/10 at 1:50pm
Quote:


Could the impedance on the capacitor I put in the power board, not be suitable for the power board, even though the capacitance matches?

yes, since these are in an SMPS you should at least match the ESR.
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post #25 of 38
5/5/10 at 4:57pm
Quote:
Originally Posted by ClearToLand View Post

If this were MY television, at this point I would buy myself a SAM's schematic and start checking voltages rather than guess that 'your problem sounds like his problem so change this'...

I don't know if your comments are targeted at my posts. The reason I asked the OP to try those backlight settings was for troubleshooting, in hope to narrow down the source of the problem. As I clearly stated, changing those settings were in no attempt to directly fix OP's problem. Now that OP mentions that backlight level does change on various settings, I would tend to think the problem is more towards the backlight hardware than power supply. With a power supply problem, I would think backlight output would be limited at best (if everything else works with enough power), not a reduced backlight by a percentage.
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post #26 of 38
5/6/10 at 12:23pm
Quote:
Originally Posted by CHrisCHu View Post

I don't know if your comments are targeted at my posts...

Nope, not at all.

Although I'm probably 'preaching to the choir', I wanted to point out that just by reading a forum you cannot instantly become an experienced electronics tech. Your explanations of "10 is 100%", Master and Auxiliary Backlight controls, Inverter vs Bulb vs Power Supply were all good troubleshooting *AND* clear communication for the rest of us LURKERs.

I re-QUOTEd and BOLDed what I felt were 'Key Points' in the thread thus far, using RED for further emphasis, in an attempt to guide the OP.

The questions that remain for me are:
  • Is the backlight emitting enough light?
  • If not, is it due to the bulb or the power to the bulb?
  • If yes, what would cause the LCD panel to run 'darker'?
These are just 'Logically Thinking the Problem Out' questions - my training was 30+ years ago on an 'ancient' technology. While a Samsung tech might be able to come in and 'probably' guess the correct component to replace (based on experience), IMO, the average tech would need a schematic in order to make some voltage checks. Then, at least it becomes 'Educated Guesses'.

Statements like:
Quote:
Originally Posted by xdajzax View Post

...Should I use 1000uF and 10V as was initially on the board? Or higher voltage. What about a higher capacitance component? what would happen if i used 2200uF, will that deliver more power, and more light to the TV?

along with the fact that the OP *STILL* went along with the 'Clogged Fuel Filter' / 'Kinked Garden Hose' analogy indicate to me a complete lack of understanding of the problem at hand and the mechanics behind it.

When I attempt to help someone with a problem, I *DO* require that they possess at least a basic understanding of the topic (electronics, auto repair, carpentry, plumbing, electrical, etc...). If they don't, I'll warn them and then step aside.
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post #27 of 38
5/6/10 at 12:39pm
Quote:
Originally Posted by duvetyne View Post

yes, since these are in an SMPS you should at least match the ESR.

How much could that affect the output?

My rusty old brain tells me there are specific purposes, and tolerances, for ceramic, mylar, tantalum, etc... so I wouldn't replace a tantalum with a mylar, but tantalum with tantalum, for example - would RadioShack vs 'Brand Name' matter regarding ESR?
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post #28 of 38
5/6/10 at 10:43pm
It is okay to increase the capacitance value slightly in this circuit (maybe 20% higher) and still work properly. As you already know, you can also increase the voltage values as long as physically the component fits. These components are DC filters, they don't have to be the exact value to function properly in this circuit. Another thought, have you checked the polarity of the capacitors you installed? Is the polarity correct? There is a "-" symbol on the side of the capacitor that must be followed when installing. If not, this can cause a number of other issues, such as the one you described. If the panel backlight brightness was fine before it failed, and you found vented caps only, I've got to believe the new parts were incorrectly installed. May be an easy solution.
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post #29 of 38
6/17/10 at 8:11am
I have the same problem. I fixed the clicking by replacing capacitors but I am trying to figure out how to fix dark/dim screen. I looked at other forums and they suggest that LVDS cable and T CONN board going bad. I am thinking on giving a try and replacing it.

Did you find solution to your problem?
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post #30 of 38
12/4/10 at 7:05am
I'm having the same exact issue as you have had. Did you find a solution?

Replacing the caps solved the clicking and the TV turns on fast but the picture
is very poor and dark. It also seems as if the refresh rate of the picture is slow.

Quote:
Originally Posted by xdajzax View Post

My Samsung LN-T4661 (3yrs old) had been working fine x 3 yrs until 2 days ago, when it blacked out. When I tried to turn it on, it would cycle through clicking, with no picture. The symptom was exactly as shown below in the youtube videos i found.

youtube.com/watch?v=Mm51C_RDIZE
youtube.com/watch?v=BNHHrgX_6cs&feature=related

On the power board (BN44-00168B. vparts4less.com/images/Power%20Supply%20Main%20BN44-00168B.jpg ), there are 6 capacitors in the cold section. 3 are 1000uF 25V, and 3 are 1000uF and 10V. The three rated at 10V were fried. I replaced yesterday with 2 1000uF 35V and 1 1000uF 50V (there were the only ones I could find at Fry's and Radioshack, and as I understand it, you can replace with higher rated capacitors).

Awesomely enough, that fixed the problem of the clicking. THe TV now turns on, but the picture is dim. I have the contrast and brightness up 100% with backlight on 10 and it's still dim. I'm now considering the following:

1) I inadvertently fried one of the capacitors I installed. (I'm not an electrician and had a cheapo soldering iron that didnt get too hot).

2) The firmware needs to updated. I'm praying this might be the problem. I never had to update the firmware since purchase, so I'm skeptical this will work.

3) Somehow, the repair of the power board, made the inverter malfunction? not sure about this. I never opened or touched this part of the TV. Also, if it was malfunctioning, wouldn't the TV just not turn on?

HERE is what I'm planning:

1) I'm gonna buy some more capacitors and try to replace again. I've got nothing to lose here, because if it doesnt work, I;ll buy a new power board.
Should I use 1000uF and 10V as was initially on the board? Or higher voltage. What about a higher capacitance component? what would happen if i used 2200uF, will that deliver more power, and more light to the TV?

2) If 1 doesn't work, then Ill swap out the board.

I AM A TRUE NOOB when if comes to circuit boards and TVs in general, so PLEASE HELP with your insights and suggestions.
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