hp laserjet 4 error 50
When warming up, your HP Laserjet 4 shows the following message on the LCD panel:
This may have several reasons:
- A burnt out quartz fusing lamp:
- A good fuser lamp should have about 6 to 8 Ohms (the 110 Volts version about 2 Ohms)
- The lamp is connected to the right (larger) contacts of the fuser-unit
- A defect power supply:
- While the printer is warming up, the power supply outlet for the fuser unit should
provide about your mains voltage for some seconds.
- If it does not, the triac or the optocoupler which switch this output, might be defect.