Brother Printer Error Code 51 — What It Means & How to Fix It

What Does This Error Mean?

Brother error 51 means there is a problem with the drum unit in your laser printer. The drum unit is the green cylinder that transfers toner onto paper. It may need cleaning, reseating, or replacing depending on its age and condition.

Affected Models

Brother HL-L2350DW
Brother HL-L2390DW
Brother MFC-L2710DW
Brother MFC-L2750DW
Brother DCP-L2550DW

Common Causes

The drum unit has reached its expected lifespan and needs to be replaced
The drum unit is not seated correctly in the printer
The drum's electrical contacts are dirty, preventing proper communication with the printer
The green drum surface is scratched or damaged from handling or foreign objects
A third-party drum unit is not being recognized by the printer

How to Fix It

Open the front cover of the printer. Pull out the toner cartridge and drum unit together.

Place them on a piece of paper or cloth to avoid toner dust getting on your desk.
Separate the toner cartridge from the drum unit by pressing the green release lever. Inspect the green drum surface for scratches, marks, or debris.

Do not touch the green surface with your fingers — skin oils can damage it.
Clean the corona wire inside the drum unit. There is a small green or blue tab on the drum unit — slide it gently back and forth several times.

The corona wire charges the drum. If it is dirty, print quality drops and errors can occur.
Reinstall the toner into the drum unit, then slide the whole assembly back into the printer. Close the front cover.

Make sure everything clicks firmly into place.
If the error persists, replace the drum unit. The drum unit is a separate part from the toner and wears out after roughly 12,000 pages.

You can buy a replacement drum from Brother's website, Amazon, or office supply stores. Your toner cartridge can be reused in the new drum.

When to Call a Professional

You can replace the drum unit yourself — it is designed to be user-replaceable. If error 51 persists with a new genuine drum unit, the printer's drum sensor or corona wire may need service. A professional repair for this issue typically costs $40 to $80.

Frequently Asked Questions

How often does the drum unit need to be replaced?

Brother drum units typically last about 12,000 pages. This is an estimate — actual life depends on what you print. Documents with lots of dark areas wear the drum faster than lightly printed pages.

Is the drum unit the same as the toner cartridge?

No, they are two separate parts. The toner cartridge holds the black powder that makes the image. The drum unit is the roller that transfers that powder onto paper. You replace the toner more often than the drum.

What is the corona wire and how do I clean it?

The corona wire is a thin wire inside the drum unit that gives it an electrical charge. You clean it by sliding a small tab back and forth inside the drum unit. Do this gently — the wire is fragile and can break if you push too hard.