I have a GBC model 4250 laminator that when you turn on the power switch, it immediately says it is ready. It does not heat up at all, let alone to normal operating temperature. Can anyone help?

Brian, December 2011

fix all brands of roll laminating machines for a living. As another posted the sensor transistor has failed. Easier access by pulling power plug from wall:( removing end covers, removing 2 screws that allow the back panel to fall open, remove the bottom film idler bar, its spring loaded its in front of machine directly under bottom orange roller. the 2 screws behind the idler roller hold the spring loaded assembly together. the small plug assembly contains a LM 135 precision temp sensor transistor around 12 bucks from digi key. or you can buy that small temp sensor board for just under 300 bucks from GBC:( remove the brass plate to access the transistor.

this generally fixes the always ready machines, the other failure has the machine overheat and take out the thermal fuse, the heavy wired thing on the spring loaded assembly.

replacing the spring loaded bracket is easiest with a helper, to line up the screws. you cant see both sides of the machine at the same time.

this must be the most common gbc 4250 failure recently, this issue comes up often here

bob haller service and sales pittsburgh pa 412 366 4906, December 2011

There's a temperature sensor under the bottom heat roller. If you remove the two side panels (three screws on each side), you can unscrew the bottom grill four screws and nuts). The sensor is held by two screws. I've found that by cleaning the gunk off the sensors using very fine sand paper, they start working again.

Dave, December 2011