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Jack
Jack, Technician
Category: TV
Satisfied Customers: 8352
Experience:  40 years experience as audio,video repair and installation tech
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I have a 46" Samsung LCD TV, Model Code LN T4669FX/XAA.

Customer Question

Hi Jack,
I have a 46" Samsung LCD TV, Model Code LN T4669FX/XAA. About 8 years ago I replaced the two 2200uf caps on the BN44-00168B SIP460A SAMSUNG Power Supply, LNT4661FX/XAA LE46S86BDX/XEU.
Starting last year when turned, on it would present a varying light/dark gray
mottled screen. After several off/on attempts, it would work properly. I started leaving it turned on 24/7 and that worked for a few months.
Recently, there were green streaks horizontally and would turn off and on for a couple of seconds. There were repeated sound interruptions requiring off/on switching. Last week when turned, I got a momentary picture, green screen, no sound, and off.
I pulled the power supply board, figuring the replacement caps had died again. They appeared fine, with no sign of defect. I visually inspected the PS board with no obvious defects.
I considered buying a new PS, but I prefer to find the problem before moving on. I also inspected the other 2 boards, but nothing was obvious.
Thanks in advance,
Bill
Submitted: 5 months ago.
Category: TV
Expert:  Jack replied 5 months ago.

Hi and thanks for the request

Expert:  Jack replied 5 months ago.

Those arre certainly signs of a defective power supply and yes it could be still caused by bad capacitors .

I mean considering the age of the tv , it is ripe for it and they do not always show signs of defect like that round op , it is just a sure sign of defect

Is the tv turning on at all now ?

Expert:  Jack replied 5 months ago.

By the way , you could try this capacitor kit for $14 and that would tell you if the capacitors are the problem

http://lcdalternatives.com/Samsung-LN-T4669F-IP321135A-LCD-TV-Replacement-Capacitors-Board-not-Included-P4879351.aspx

Expert:  Jack replied 5 months ago.

Only thing that bothers me here are those green horizontal streak so if you could get to see them again , open the tv`s own menu to see if it covers them or you can still see them over the menu ?

Expert:  Jack replied 5 months ago.

Anything horizontal on the screen is not caused by the t-con and if it shows over the menu then its not in the signal from the main board either , the menu supersedes that signal and in that case the only thing left is the lcd panel itself

Expert:  Jack replied 5 months ago.

Other than that the problems that clear themselves after warm up usually come from poor filtering (caps) from the power board although some of those voltages and sub voltages are located on the main board as well but that cap kit would tell you that .

Right now you could have compounded problems and it would not be rare for a tv of that age

Expert:  Jack replied 5 months ago.

Try the capacitor kit and that will tell you where to go next if that doesn`t clear everything , I mean that for $14 it certainly is cheaper than buying a new power board just for a try !

Let me know if you have other questions and if not for now then please do not forget to rate by clicking on the star icons at the top, then click on Submit so i get paid for my time helping you .
Also note that the rating does not close this post , you can come back at any time if you have questions or need help at a later time
Thank you

Customer: replied 5 months ago.
1. TV is off and apart.
2. Originally only replaced the 2 obviously bad caps, still look good.
3. Have 2 caps delivered today.
4. I guess I should install new caps and power up to see if I have a working screen.
5. The voltages I should check before closing are located where?
6. If it works and still has green lines, we can try the menu.I'll get back to you when up and running, today or Tue.
Thanks
Expert:  Jack replied 5 months ago.

No problem but that kit would`ve been the best try

Expert:  Jack replied 5 months ago.

let me know

Customer: replied 5 months ago.
Will do and is my communication clear and useful?It might be easier on the phone at the menu stage, if we get there.Back to you soon.
Customer: replied 5 months ago.
When I replaced the original 2 caps, I got good info online and You Tube. Some folks replaced more than 2 caps, usually 3 were bad. My TV worked well for all this time, the 2 fixed it.(NNRN).......No need to respond now, later if needed.Jack, I don't wish to waste your time.
Expert:  Jack replied 5 months ago.

Sorry had to step out for a bit.

You`re not wasting my time a bit , everything is fine

Phone wont do much good and if you received a phone offer it was automated from the web site ,not from me

Start with those and see if there are any improve. but mainly try to get it toturn back on and look at those lines and the menu , that's the first thing to do .

If your panel is defective then no need to waste time with the rest

Customer: replied 5 months ago.
What do you think of the power panels sold online? http://www.ebay.com/itm/371625107168?rmvSB=true
Are there any voltages I can check on the power panel when powered up, to determine if it's OK? If so and it is OK, that may indicated the other panel is the problem.
Expert:  Jack replied 5 months ago.

Talking about the LCD panel , the screen

Expert:  Jack replied 5 months ago.

That power board is so cheap , almost not worth trying to fix yours

Customer: replied 5 months ago.
if we can determine it's the power board, I would replace it. I'll change the 2 caps and get back to you.Again, are there any voltage points I can check, 5 or 3.5 volts?
Expert:  Jack replied 5 months ago.

Your best tester is replacing those unless you have an oscilloscope handy to check the ripple on the DC lines

Expert:  Jack replied 5 months ago.

Those voltages should be written next to the connectors , take a look

Expert:  Jack replied 5 months ago.

Next to connector CN801 on the power board , can you see the pinout voltages printed on the board ?

Those are your voltages