Repair question: Samsung LCD model LN52A530P1FXZA

Hello, folks. I recently purchased a Samsung 52 inch LCD tv from a friend of mine. Model LN52A530P1FXZA. It stopped working after about a week from purchase. I called Samsung and find out it qualifies for a free repair due to faulty capacitors and/or motherboard. The technician came by today and replaced the capacitors. He plugged it in directly to the wall outlet, power cycled it about 8 times with no problem. 5 hours later, I decide to mount it back up, but I wanted to make sure it was still working. I plugged it directly to the wall outlet, and it came on, but only stayed on for about 3 minutes. I unplugged and replugged it multiple times, but still to no avail. I then plugged the TV into a power strip and it powered up and has been working perfectly for the last hour. Any reason why this was the case? I find it strange that the technician who used the same wall outlet I did had no problem with it, but I was only able to get it to power up successfully using a power strip. Any info would be appreciated. Thanks.

Nope, sorry. I bought the tv used without the original stand.