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 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.