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Anthony_Infotech
Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 13711
Experience:  20+ years experience TV expert (field and bench) 9 approved qualifications in TV-ELECTRONICS
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I have a Samsung LNT4069F TV, built in 2008, that will not

Customer Question

Hello, I have a Samsung LNT4069F TV, built in 2008, that will not turn on.
We stopped using this set about 2 years ago because it would take so long for it to come on. We would have to cycle it on and off several times before we would get a picture. Eventually it did not work at all. I researched and learned that some of the capacitors will overheat and bulge at the top. I did find 2 or 3 like that and replaced them. The result, however, was the same - no picture, no logo. Just a black screen.
When I press the power button the light sometimes goes out completely and sometimes blinks at 1 second intervals. If it goes out, it will not blink until the power switch is turned off then on again. When it blinks, it does so continuously at one second intervals.
When turning it on I always get the 4 or 5 note audible chime.
I have checked the 2 things that look like fuses - cylindrical and about 3/4 inch long and 1/8 inch in diameter. If they are fuses, they check out ok - abou
Submitted: 1 year ago.
Category: TV
Expert:  Anthony_Infotech replied 1 year ago.

Hello

Welcome

Firstly you did right to replace the capacitors its a common issue with samsung sets however did you fit these in correctlly?where they the same values as the ones that came out, and did you fit them in the correct way around?they are polarized.

Let me know about that first please before we move on.

Thanks

Anthony

Customer: replied 1 year ago.
I matched all the specs on the capacitors and was careful about the polarity. The diy I followed was very detailed.
Expert:  Anthony_Infotech replied 1 year ago.

OK that's good did you replace all the capacitors?or just the ones you seen as bad?

Customer: replied 1 year ago.
Only the ones that were bulged on top
Expert:  Anthony_Infotech replied 1 year ago.

OK two things here, more of those capacitors are bad you may need to replace them all in that group OR the main-board is bad (caused by the bad capacitors) or both, you should replace the rest of them, try the set again, however in most cases were I come across this the main-board has been damaged by poor regulation of the voltages supplying it from the power-board ie those bad capacitors, the result is exactly the same symptoms as when the power-board is bad with bad capacitors.

There is no way of verifying for sure you just have to follow this procedure (unless you have an ESR meter) replace the capacitors then if necessary replace the main-board let me know you understand this then I will tell you about the main-board

Anthony

Customer: replied 1 year ago.
Is the main board the same one i replaced the capacitors on? If so why not just replace the board now?
Expert:  Anthony_Infotech replied 1 year ago.

No the main-board is the one with all the AV input connectors on sorry I should have pointed that out

Customer: replied 1 year ago.
Rather than replace all the caps on my board, I can get this Power Supply Backlight Inverter Board Unit used and guaranteed.
Exact same id numbers as on mine.
http://www.ebay.com/itm/Samsung-40-LNT4069FX-BN44-00167C-LCD-Power-Supply-Backlight-Inverter-Board-Unit-/361258914593?hash=item541cb59321:g:E3AAAOSwBLlVHH~7
What are your thoughts on that?
Customer: replied 1 year ago.
Ok. I replaced all 6 capacitors and still get the same result. Do you think it's ok to get a used main power supply board? Seller guarantees it is in good working condition.
Expert:  Anthony_Infotech replied 1 year ago.

Sorry I thought I made myself clear above its NOT the power-board I am referring to .......it's the MAINBOARD the one with all the AV input connectors on, you have now cleared the power-board and MUST replace the main-board' do this by part-number only

Let me know you understand thank you

Anthony

Customer: replied 1 year ago.
I may have used the wrong terminology. So to be clear, I replaced the four 10V and two 25V capacitors on the inverter board. Initially (a year or so ago) I only replaced the one that was bulged on top, but now all 6 have been replaced. I still have a black screen.
I have ordered a replacement MAINBOARD (used but said to be in working order). This is the board with all the inputs if I'm correct.
I will let you know the result when it arrives, probably around Oct 30.
Expert:  Anthony_Infotech replied 1 year ago.

Yes hopefully you ordered by part-number only.

Yes its the powerb that damages the main-board same symptoms are experienced.

Let me know

Anthony

Expert:  Anthony_Infotech replied 1 year ago.

Do you still need any more help with this please?

Please consider rating the answer positively thank you there will be a rating band with this post, rating me positively enables me to receive credit from the site, thank you, ***** ***** will remain open and stay open as long as you need it, if you have any concerns please don't rate instead just let me know and I will answer any queries you have

Many Thanks

Anthony

Customer: replied 1 year ago.
Waiting for the board to arrive. Should have it by Friday. I'll let you know when I get it installed.
Expert:  Anthony_Infotech replied 1 year ago.

OK

Anthony

Customer: replied 1 year ago.
Anthony,
I received the main board and installed it. I get the same result. Before I press ON button the light beside the button is on steady. When I press ON button, blue light at base of tv turns on, power light beside the on/off button goes out then blinks 4 times, goes out. I have a solid black screen the whole time.
Expert:  Anthony_Infotech replied 1 year ago.

Are both partnumbers of the mainboard exactly the same?

Customer: replied 1 year ago.
Exactly. I checked that before I installed the board.
Customer: replied 1 year ago.
Is it possible the light board is bad. I get 12V coming out of the power board to the long board on the left of the power board. I assume this long unit is what produces the light. There are 2 connectors, one on top one on bottom.
Expert:  Anthony_Infotech replied 1 year ago.

I suggest you send the board back as bad, there really is nothing else the inverters will not cause the set to behave this way I suppose you could unplug the inverters but the set will go off anyhow but it may do something different, I cant see the inverters causing this issue

1 in every 5 boards can be bad they are pulled from scrap sets, maybe you should get the powerboard too if its cheap enough

Anthony

Customer: replied 1 year ago.
I don't think I'm willing to put any more money or time into this thing. The only way to be sure it's a good board is to get a new one and they are over $200. Guess it's time to replace the set
Expert:  Anthony_Infotech replied 1 year ago.

OK

Let me know if I can do anything else

Please remember to rate the answer positively thank you there will be a rating band with this post

Thanks Again

Anthony

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