Hi guys. I have an old corded Bosch PSB 600 RES and i can not open or close its chuck anymore.........it is a sort of stuck. Could anyone please advice me on how to remove its chuck and where i can get a replacement one which is not going to cost me more than a new drill? I do not want to choke it away because apart from the chuck it works ok and i can keep it for general diy around the house. Thank you for your time.