Hi, Working on a SPC 420 fault very feint image, sub toner pump seized, replaced, after switching on K pump rotates constantly, disconnected motor and fitted new pcu, set up ok and ran a few copies all ok, connected K pump motor, runs all the time, don't want to risk breaking new toner pump so any ideas? VT ref ok compared with another 420 working. Tried another i/o board same fault.