Quote Originally Posted by Gambo View Post
Hi I don't know you machine but from what you say since the bed is warming up and the machine is displaying the bed temp the fault is most likely to be the semiconductor switch whic switches off and on the power to the heated bed. That would be consistent to a short circuit across the dc power to the heated bed.
I dont know where this is located on your machine but probably on the main board.
Thanks I've tried replacing the heated bed circuit board but that hasn't fixed it. I now have a replacement driver board on order - that's where the power to teh bed comes from. If that doesn't fix it I'll order a new motherboard. I'll let uou know how I get on. Cheers.