This may not be the same problem but it sounds like it could be related.
http://www.amazon.com/Samsung-LN40A550-40-Inch-1080p-HDTV/dp/B001418W2C
I purchased the Samsung LN40A550 40" 1080p LCD HDTV on July 14, 2008. It's my 4th big screen HDTV purchase but my first 1080p box. Agree with other reviews in that it has an absolute beautiful picture at a very good price. There are many features I love about this TV, but here's the problem....
I purchased a Samsung 1080P8 upconverting DVD player with an HDMI (version 1.3) cable. When i watch a DVD, i get a 'searching for signal' message that appears on the screen for about 5 seconds. This happens once every minute or two! I went into full troubleshooting mode by replacing the cable, the DVD player, and everything else i could think of. I tried the DVD player and HDMI cable with my other HDTV sets and it worked great. After calling Samsung technical support and getting to their level 2 support in New Jersey, they acknowledged there is a problem with the HDMI connection with the TV but they do not have a firmware fix for it yet. They suggested i wait for the firmware fix (release date unknown), or return the TV and try another one. I opted to exchange the TV for the same model. I received it today and (unfortunately) it has the same problem. I will now return the TV to Amazon, get a refund, and purchase a different model.
Bottom line, if you don't use or need the HDMI connection, you should be fine with this set. However, if you plan to use HDMI I'd look to a different model until this is fixed.
Update on July 28 - After further troubleshooting, the HDMI problem is with the combination of using a Samsung LN40A550 40" 1080p LCD HDTV with the Samsung 1080P8 upconverting DVD player. Together, they do not work. Separately, the upconverting DVD player works perfectly with other TVs, and the Samsung LN40A550 works fine with another upconverting DVD. I purchased the same brand so i would eliminate this exact problem! Who would think that Samsung has not tested their own product compatibility before they go out the door? Exremely poor quality control - my guess is they have a problem with their 'anynet' software feature, but it still blanks-out with 'anynet' turned off. Purchase the Sony upconverting DVD player with this TV and you'll be OK. However, now I personally don't trust Samsung.
The comments for this review also talk about this being a known problem with some but not all of this model. And one even seems to describe the exact problem you are having. I suggest you call Samsung and see if they have a firmware update yet or any other suggestions that might help.
Dean
