Fan For Mary's Thinkpad
PC serial number R9KC621
Original Fan FRU # 04W1578
Parts lookup by machine serial: <a href=\"https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-w-series-laptops/thinkpad-w520/4270/4270cto/r9kc621/parts?linkTrack=Caps:Body_SearchProduct&searchType=6&keyWordSearch=r9kc621\">https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-w-series-laptops/thinkpad-w520/4270/4270cto/r9kc621/parts?linkTrack=Caps:Body_SearchProduct&searchType=6&keyWordSearch=r9kc621</a>
Compatible part numbers from link above:
75Y5786 - Furukawa 55W
75Y5778 - AVC 55W
04W1574 - Delta 55W
04W1575 - AVC 55W
04W0437 - Furukawa 55W
75Y5788 - Furukawa 45W
75Y5780 - AVC 45W
04W1576 - Delta 45W
04W0438 - Furukawa 45W