No Picture but Sound Works Fine. Any Experts Here? - AVS Forum
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Old 12-04-2013, 12:15 PM - Thread Starter
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I purchased a Samsung LN46C600 (Amazon Link) on Cyber Monday, Nov 29, 2010.

 

This past Thanksgiving, Nov 28, 2013, we were watching the Thanksgiving Day Parade when all of a sudden BOOM the picture goes out. In a flash. Just like that. The sound is fine, just no picture.

 

I give the dates because if you notice that is 2 years and 364 days EXACTLY. (What the heck Samsung; was that planned just so people buy new TVs??)

 

So I unplug it for 24 hours like a few Google posts suggest, but still no go.

 

I did the flashlight-in-a-dark-room test and I can indeed see the picture really really faintly, so perhaps the backlight is just out.

 

After a ton of researching and watching shopjimmy.com YouTube videos, I order a brand new Inverter (eBay Link) and install it myself. Still no picture, darn.

 

Other people say that the capacitors on these TVs fail, but none of mine are bulging or popped.

 

Any ideas what could be the issue?

 

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Old 12-05-2013, 05:35 PM - Thread Starter
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Doh. Anyone?

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Old 12-06-2013, 02:43 AM
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Check to see if the inverter board is getting power.
Check to make sure there are no blown fuses on the main power board.
Be careful not to touch any high voltage points on either board.

Daniel Lang
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Old 12-06-2013, 04:30 PM - Thread Starter
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Quote:
Originally Posted by dblang View Post

Check to see if the inverter board is getting power.
Check to make sure there are no blown fuses on the main power board.
Be careful not to touch any high voltage points on either board.

Daniel Lang

 

I checked all the capacitors and none of them are bulging or blown. By "fuses", did you mean capacitors or something else?

 

How do I check to ensure the inverter board is getting power?

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Old 12-07-2013, 02:11 AM - Thread Starter
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Here's a picture of the power supply board. See anything wrong with it?

XXQUimK.jpg
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Old 12-07-2013, 07:08 PM - Thread Starter
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How would you attack this problem?

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Old 12-08-2013, 06:14 AM
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I cannot see anything visibly wrong with the board but you can try measuring the resistances of the 2 fuses with the power off
(white cylinders labeled T3.15AH250V and T6.3AH250V).
Wait at least 10 minutes after power off the TV before handling the board and make sure the 100uF 450V capacitors are
discharged below 20 volts.

You can also try measuring the output voltages on CN802 and CN801 with the power on.
Be careful, CN801 puts out 720 volts! eek.gif I assume this supplies power to the inverter board.
Use a multimeter with safety tips and do not touch the board while it is plugged in.

If the problem is not something obvious, you may have to buy a new power board.

Daniel Lang
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Old 12-08-2013, 10:40 AM - Thread Starter
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Quote:
Originally Posted by dblang View Post

I cannot see anything visibly wrong with the board but you can try measuring the resistances of the 2 fuses with the power off
(white cylinders labeled T3.15AH250V and T6.3AH250V).
Wait at least 10 minutes after power off the TV before handling the board and make sure the 100uF 450V capacitors are
discharged below 20 volts.

You can also try measuring the output voltages on CN802 and CN801 with the power on.
Be careful, CN801 puts out 720 volts! eek.gif I assume this supplies power to the inverter board.
Use a multimeter with safety tips and do not touch the board while it is plugged in.

If the problem is not something obvious, you may have to buy a new power board.

Daniel Lang

Thank you! Will this multimeter suffice?

438mxCX.jpg
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Old 12-09-2013, 01:06 AM
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It will be OK for measuring the continuity of the fuses but is a bit low for the 720V output (meter only goes to 600V).

Daniel Lang
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