How long does a fuser last?

HP fusers are rated for 100,000-200,000 pages depending on the model. Heavy use can wear them out sooner.

Can I use a third-party fuser?

Yes, but quality varies. Use fusers from reputable third-party manufacturers. Poor-quality fusers can cause additional errors.

HP Laser Printer Error 50.4 — Fuser Power Supply Failure

Criticalhp

Overview

HP laser printer error 50.4 indicates a fuser low-voltage power supply failure, caused by a faulty fuser unit, power supply board, or electrical connection issue.

Key Details

50.4 specifically indicates the low-voltage power supply to the fuser has failed
The fuser heats toner to bond it to paper — without it, pages come out with loose toner
Common on HP LaserJet Pro, Enterprise, and MFP series printers
The fuser is a consumable part with a rated duty cycle (typically 100K-200K pages)
Error persists through power cycles until the fuser or power supply is replaced

Common Causes

Fuser unit reached end of life (worn heating element or thermistor)
Low-voltage power supply board failing to deliver correct voltage to fuser
Loose connector between fuser unit and printer main board
Power surge damaging the fuser's electrical components
Incompatible or refurbished fuser unit installed

Steps

1Turn printer off and unplug for 30 minutes to let the fuser cool completely
2Remove and reseat the fuser unit (consult printer manual for fuser access)
3Check fuser connector pins for damage or carbon buildup — clean with isopropyl alcohol
4If reseating does not help, replace the fuser unit with an HP-compatible replacement
5If the new fuser still shows 50.4, the low-voltage power supply board needs replacement