Rune, I had previously posted the wrong replacement fan, apparently OEM power supply fan hard to find, a lot of links say fan not available, plenty of complete power supplies though if you had too go that way. Check the link below, Kenny tells how he installed a replacement fan 10x10 fan from Mouser BFB0512HHA-C with good results. Hope this helps.
https://www.reddit.com/r/xboxone/comments/3n1atm/xbox_one_power_supply_fan_fix_or_replacment/