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Shahid
Shahid, Technician
Category: TV
Satisfied Customers: 9465
Experience:  I have been repairing electronic gear since 1993 as a qualified Sony tech
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Samsung HDTV video turns off after a few seconds but audio

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Samsung HDTV video turns off after a few seconds but audio still works. I am trying to figure out if there is a fix or I need to go shopping :(
JA: Just to clarify, what's the HDTV's exact make and model?
Customer: LN46B640R3FZA SAMSUNG VERSION AC03
JA: Does the TV menu work? Do you have the same problem on all sources/inputs?
Customer: Last week a circular black spot appeared on it and this morning this started happening
JA: How long has this been an issue? What happened right before this popped up?
Customer: I tried unlpugging it and going to all the inputs and they all have the same issue
JA: Anything else you want the TV expert to know before I connect you?
Customer: not that I could think about, thank you.

- Does TV screen glow/ show backlight when turn On the TV?

- Does any graphics appear on screen?

Hello, I'm Shahid. Sorry to hear that you're having trouble with this but I'll do my best to help.

Did you get above info request?

Customer: replied 2 months ago.
No glow and no graphics after the few seconds I do have a picture.
Customer: replied 2 months ago.
are you there?

OK, please shine a good flashlight on screen with 45 degree, do you see/ observe a faint/ dim image inside screen while having sound from TV speakers?
This test will help to diagnose the problem.

Yes, I'm here and typing the reply takes little time.

Customer: replied 2 months ago.
Sorry...I have never used this service so I am not familiar with the SOP's
no light whatsoever.
Customer: replied 2 months ago.
Sound works just fine.

No problem, I'll explain how this site works when needed.

I understand screen has no light and did you get my suggestion to shine a good flashlight on TV screen while TV is ON.

You would observe faint/ dim image inside screen with help of flashlight test.

Customer: replied 2 months ago.
I did the flashlight test as you told me but nothing under the screen

OK, working on it, give me 5 minutes please.

Customer: replied 2 months ago.
sure, thank you!

This kind of problem mostly occurs due to power supply board failure that provides different voltage supplies to other circuit boards/ sections of TV, however, some times main processor board where all video inputs are located also found bad. Since TV gives sound output but screen stays black that points out power supply board failure that will be replaced.

Please click following link to view power supply board image and part number info (please cross check the part number written on label pasted on power supply board in TV before ordering the board) that can be used to search/ google to get price info to order it if you have plan to do-it-yourself..

http://www.shopjimmy.com/samsung-bn44-00265b-power-supply.htm

If you are not comfortable working on it yourself then you may please use following link to get list of TV repair shops in area which will help to get repair quote around $200 to $250...
http://www.tvrepairpros.com/
I'm sorry there is no easy or quick fix for this problem and it is definitely hardware failure that needs defective board replacement to resolve the issue.
I trust my input will help you out to make decision about this TV repair or invest that money on new replacement TV.
If you have any additional questions, feel free to ask. If you're satisfied, please rate me a 5-star at the top of your page.
Thank you.

Customer: replied 2 months ago.
If that were the case, wouldn't the screen not turn on all together instead of turning on then turning off?

Let me explain, typing the info that will take few minutes..

Customer: replied 2 months ago.
Sure, thanks!

There are few capacitors, resistors and regulator chips mounted on power supply board. A failing capacitor or devalued resistor or failing regulator chip/ IC can cause insufficient voltage supply to activates the protection circuitry on power supply board to avoid any further damage, protection circuitry switch Off that section for example backlight inverter section or 12V supply line etc.

Sound output from TV is another evidence that shows main processor board is keep working but backlight system switches Off after some time when detects any error so screen goes dark but rest of TV stays On so you keep getting sound output from TV internal speakers.

These are the reasons that my diagnosis is based on. I hope these info will help. If you have any additional questions, feel free to ask.

Thanks.

Customer: replied 2 months ago.
Makes more sense. Thanks!

You're welcome. If you're satisfied, please rate me a 5-star at the top of your page.
Thank you.

Shahid and 3 other TV Specialists are ready to help you