No power on Hewlett Packard LaserJet’s 4200, 4300, 4240, 4250, 4350, P4010 and P4510 printer series Printers
Check the power cord at the wall outlet and test for power. If good, check the connection on the machine side of power cord. The following is for printers with duplexers. If it doesn’t have a duplexer see the second illustration and push the power cord into machine.
Next, Pull Duplexer halfway out of printer. Push the power cord into machine as far as it can go to make sure there is a good connection.
If this is good you will need a Power Supply assembly.
Do-It-Yourself Printer Repair 