Hi, I've got a Replicator 2 with 600 hours on it and it suddenly won't print. I can change the filament fine, and feed it for a while. but when I load a project it doesn't feed the PLA and starts clicking. I've disassembled, cleaned & replaced the drive gear, but no change. I've also raised the temp from 230 to 240 but nothing. Any advise would be greatly appreciated.