The Samsung LN46C630 TV has a known issue with screen flickering after the warranty has expired. Rather than pay $150 at your local repair show, fix it yourself in 15 minutes!
The fix for this issue is easy. There is a jumper on the power supply named JP852. If you cut that jumper, the screen flicker will no longer happen. I do not know what JP852 is used for, but apparently there is a service bulletin from Samsung for this fix. Thank you to Denise from an Amazon.com review (here) who provided the details on this fix.
Please assume this will void your warranty and potentially break your TV. After doing this fix on my own, my TV has been running fine since February 18, 2012 . I will update this guide if for some reason my TV stops working.
UPDATE June 14, 2012: It has been a few months and my TV still works great!
UPDATE December 31, 2012: My TV is still going strong. NO ISSUES TO REPORT!
UPDATE March 16, 2013: All is well! It has been over 12 months since I cut the jumper and everything still works as well as the day I bought it.
UPDATE June 19, 2013: Still going strong. NO ISSUES TO REPORT!
UPDATE October 19, 2015: NO ISSUES TO REPORT!
UPDATE February 23, 2017: NO ISSUES TO REPORT!
Step 1: Symptoms
The symptoms of this issue are mostly described as "screen flickering". It mostly happens intermittently at first, then gets progressively worse. HDMI connections start first, then component, etc. If the user turns the TV off, then on, it usually fixes the issue for a little while, but it eventually comes back. After a month or two, the screen will flicker be permanent.
The model fixed in this tutorial is a LN46C630K1F. This fix is supposed to work for all TVs in this class. I did see something online about this issue happening on other Samsung TVs in a different class and the fix was cutting a different jumper.
Step 2: Remove the Back Cover of the TV
There are 18 screws (there is a harder to find screw in between the two rows of component jacks). A normal sized Phillips head works. If you are leaving this TV on the stand base, remove the bottom two screws last and be careful, it just sitting on that base without any screws! I recommend replacing the bottom two screws after you have the back cover off so you TV does not fall off the base.
Step 3: Find the Power Supply
The power supply is located where... the power cord plugs in!
Step 4: Find Jumper JP852
Jumper JP852 is located on the power supply in the top left corner just below the 46. It connects something labelled 'Input rating' and another labeled 'COLD'
Step 5: Cut Jumper JP852
This is easy and you can probably just use scissors. Cut the jumper on the middle and separate the wire so it doesn't touch. Put the case back on the TV and you're done!