HP 50.x Fuser Error (50.1–50.4) — Fuser fault family

What this error means

The fuser failed a temperature check: 50.1 low temperature, 50.2 warm-up failure, 50.3 high temperature, 50.4 line-voltage problem. The printer locks out until the condition clears.

Symptoms

• Printer stops with 50.x on display
• 50.4 often appears when the printer is on a UPS or power strip

Try this first (safe DIY steps)

1. Power off for a full 10–15 minutes (fuser errors can latch until the unit cools), then power on
2. For 50.4: plug the printer directly into a wall outlet — never a UPS
3. If your model has a user-replaceable fuser (many Enterprise models do), reseat it

Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.

When to call a technician

If the error survives a cool-down and direct wall power — the fuser needs replacement. On many HP models this is a DIY part if you're comfortable.