PS1 (Input/Registration Sensor) Check
1 Power ON the printer with the top cover open. Wait for the 12 PRINTER OPEN (or CLOSE PRINTER COVER) message.
2 Engage PS1 by taping it down.
a For the LaserJet 5, install the toner cartridge.
3 Close the top cover. The 02 WARMING UP message should display.
4 After the fuser warms up, the main motor should turn on.
5 The 13 PAPER JAM message appears if the sensor is working correctly.
6 If the 13 PAPER JAM message does not appear, check that PS1 was fully engaged, then replace PS1.
7 Remove the tape from PS1, install the Toner Cartridge and close the top cover.
8 The display should change from 02 WARMING UP to 00 READY. If the 13 PAPER JAM message persists, replace PS1.
Figure