My Samsung UN40C5000 has a green screen upon start-up. When the picture comes on the subjects have a green halo around then. After a few minutes, or seconds, the picture returns to normal. It was a Sears store demo, and I have the extended warranty. Is this a simple fix, or should I just call a tech? Thanks

Dark spots might be due to energy recovery circuit board's fault. If you wish to get more details about these type of faults to Samsung TVs, check this link.

Check for dirt on the front element of the lens. I am always amazed that almost every point and shoot digital I see has a filthy lens.

This can also be caused by condensation inside the lens or on the rear element

solution
step 1 : at first test your fly back transformer step 2 : A.C. transformer test or out put voltage measurement
step 3: test your video I.C.
Send report :[email protected]

try this: Press the volume button on the T. When the on screen display come up, press and hold the MENU button for 5 seconds.

Ur convergence is dead.Must replaced 2 Convergence ICS,and some or all the resistors.Know how to solders?Buy a convergence kit Tv repair World.com,Tvrepairkits.com to repair it ur self.The shop will cost u $300 for parts and labors.

sounds like the coolant if it appears as halos. If it appears like a 3D picture its the convergence ICs.

the problem you r facing is absolutely repairable but the charges will be heavy.
now its upon you to go for new or get it repaIRED.
i will suggest you to go to repair center and get it repaired as this problem is faced by many users and it is completely repaired.

The most likely cause is shorted convergence chips and possibly a few pico fuses.

These sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the picture to look normal. This is called convergence.

When its out of alignment the video will look 3-D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired. Convergence problems are very common on all Projection TV sets including Sony,Samsung,JVC,Philip Magnavox,Panasonic,Akai,Pioneer Hitachi,Mitsubishi,Zenith and others.
You can get a convergenece repair kit with instructions from the links below.

Here are some of the most common problems with these sets...

Problem #1) Convergence

Yours may have one or more of the following symptoms...

*Screen Looks 3-D
*Colors wont align
*Screen may look distorted or warped
*No Audio/Video - TV Shuts down - May also make a constant chirping sound

Problem #2
Another common problem is dull or washed out video.

Your set may have one or more of the following symptoms....

*Dull looking picture
*White looking picture
*Halos around objects
*Red/Orange looking picture

You can see some more examples and find a fix here http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

I have a Samsung HCM5535W rear projection TV that had pretty much the exact same problem-- a green halo around bright white images. I researched it on the net, and determined the most likely problem was with the convergence STK-ICs, or the convergence board. I bought a replacement board with the STK ICs and installed it, but no luck, the problem persisted. I decided to mess with the manual focus adjustment on the green crt (i was seeing a green halo), and that fixed it. As it turns out, no replacement parts were necessary to fix the problem in the first place. Hope this helps somebody out there.

The basic colors in the TV is RGB & each color has a diff amplitude & frequenc. It seems that the IC controlling the RED & BLUE has lost some of it's capabilities due to lower voltage supplied/regulated by the chip, which generally happens after quite long period of usage. However this seems an inherent fault with visio & most of the early sets do not have this problem sorted out at the manufacturing level & is a problem for most of TV's which are unpredictable & could occur in a month or year. If still under warranty, pressurize your dealer/distributor/service center to sort it pronto or ........... face the consequence..........sodeep