BestBuy gave me a slim PS3 free, but it keeps overheating...(inside glass cabinet)

[quitemouse]

my old 80GB PS3 stopped playing discs(DVD, CD, Blu-ray) because it would not allow discs to be inserted. The mechanism probably just died.

I went to the local BestBuy and they gave me a new slim PS3 under the 2-yr replacement plan. I was a little sad, because the my old 80GB PS3 was the last PS3 with SACD-playback capability... but oh well...

I hooked up the slim PS3 and placed in the same glass cabinet as the old PS3, in the same orientation. The cabinet is not ventilated, except for a baseball-size hole which allows cables to go in and out... For more than 1 year, the old PS3 never had a problem inside, even with daily use.

After two days, the slim PS3 kept shutting down due to heating problem. if I leave the cabinet door completely open, then it doesn't do it.

Before I go back to BestBuy, I'd like to know if I might have gotten a slim PS3 with defective fans? Or is this just normal? The reason I'm asking is that unlike the old PS3, the slim PS3 made no sound at all.... none that I could hear from sitting 2 feet away. The old PS3's fan was loud enough to be heard, even inside the cabinet....

Thanks!