Epson ET3850: replace the maintenance box safely

Before you begin

Applies to: Epson ET-3850. Only the listed models; do not expand by similarity.

Confirm the exact model and current printer status before changing settings.

Step-by-step

1. Confirm the warning names the maintenance box, not the internal borderless-printing ink pad.
2. Use the model-listed T04D1 / T04D100 box and follow the LCD replacement instructions.
3. Never change it during printing. Keep the removed box upright and avoid touching the chip or openings.
4. If the cover will not fit, check seating rather than forcing it. Confirm the warning clears afterward.

Check whether it worked

Repeat the original operation and confirm the problem no longer occurs.

If it still fails

Use the exact model support page; record the full displayed message.

• Do not substitute a counter-reset utility for physical replacement.
• Do not reinstall a box that has been left removed for a long time.

Official sources

These links identify the source and its scope. Check the manufacturer page again before changing a printer setting or buying a part.

• Epson — ET3850 maintenance box replacement ↗ Checked 2026-11-01; official full page
• Epson — T04D1/T04D100 maintenance box compatibility ↗ Checked 2026-11-01; official full page

Useful next steps