Hi john g, I see you are in herts , my old neck of the woods , no pun intended, have you tried taking the 400 in for repair ? are you close to st. Albans , where did you buy it , tts will pick it up from you or your nearest store , then if you are still unhappy send it back again then see if a replacement will be offered , I know it's not what you would like but it's due proccess if you can't do without the saw explain that to tts , If no joy pm me , green.