Graphics card fan stops at high temperature

A friend of mine just gave me an ATI HD 5770 from Club 3D for free (way better than my 9800GT), as he said it broke. Apparently the fan on the card stops working when it reaches high temperatures.He had left his PC on for three months while he was away and it was during this time that this started to happen. He didn't try to fix it or take it anywhere to get it fixed, he just decided to buy a new card.

I have not yet had the chance to test it, as my new PSU only arrives on the 15th and my current replacement can't power the card.So I was just wondering if anyone knows of this issue or has any idea what might be causing it? (So I might fix it early on)

im sure you understand the "Free" reason was bc its 99% done for.

Yeah, I get that, but it won't be the first time I've been able to salvage a part... once my PSU comes I'll be able to do some propper tests to determine just how broken it is, this post is just to get a jump start on the case