Epson ET-8550 Restarts When Printing a Nozzle Check After DTF Conversion - Causes and Fixes

Question

I followed the steps in your video about converting the Epson ET-8550 printhead from mesh to nipple style. Everything seemed fine during the process, but when I try to print a nozzle check, the printer automatically restarts. Why does this happen, and how can I fix it?

Answer

From your description, the key symptom is that the ET-8550 restarts automatically when attempting to print a nozzle check after completing the DTF modification shown in the video "#1 MUST-DO for ET-8550 DTF: STOP Using Mesh Printhead - Nipple-Convert It!". When a printer restarts right when the printhead initializes, it usually indicates a hardware protection trigger-something is causing the printer's system to shut down and reboot.

In most cases, this behavior is associated with one of the following issues.

1. Short Circuit or Electrical Protection Trigger

During the nozzle check, the printer energizes the printhead and moves the carriage. If the printer detects abnormal current draw, it may shut down and restart to protect the electronics.

Common causes include:

• Ink contamination on electronic components

• A damaged or improperly seated ribbon cable

• Moisture or ink bridging contacts

• A failing printhead

DTF conversions increase the risk of this problem because pigment inks are thicker and spills during installation can reach the electronics.

What to check:

1. Turn the printer completely off and unplug it.

2. Open the top cover and locate the printhead FFC ribbon cables.

3. Carefully disconnect and inspect them for:

   • Ink residue

   • Bent pins

   • Moisture or staining

4. Clean gently with 99% isopropyl alcohol if contamination is visible.

5. Reconnect the cables firmly and evenly.

Even a tiny amount of conductive ink on these cables can trigger a restart.

2. Ink on the Mainboard or Carriage Board

Another common issue after DTF modifications is ink contamination on the carriage board or the main logic board.

The ET-8550 has sensitive electronics, and if ink reaches the board area, it may create partial electrical paths that only become active when the head powers up.

Look for:

• Ink droplets near the carriage PCB

• Ink residue around ribbon cable connectors

• Ink splashes inside the carriage area

If found, carefully clean the affected area with alcohol and allow it to dry completely before reconnecting power.

3. Damaged or Pinched Ribbon Cables

During printhead conversions or reassembly, ribbon cables can become:

• Pinched under plastic panels

• Folded too sharply

• Slightly misaligned in the connector

If a ribbon cable is damaged internally, the printer may restart when communication with the printhead begins.

Check for:

• Creases in the cable

• Exposed copper traces

• Uneven insertion into the connector

If the cable looks questionable, replacing it is usually the safest option.

4. Capping Station or Pump Jam

When a nozzle check begins, the printer performs a quick mechanical check involving the capping station and pump assembly.

If the mechanism is jammed, the printer may restart because the motor draws too much current.

Check that:

• The capping station moves freely

• The pump tubing is not clogged

• No dried ink is blocking the mechanism

You should be able to gently rotate or move components without excessive resistance.

5. Power Supply Instability

Another possibility is power instability.

When the printhead fires, the power draw spikes briefly. If the power supply or power cable is unstable, the printer may reboot.

Try:

• Plugging the printer directly into a wall outlet

• Avoiding power strips or surge protectors temporarily

• Checking for loose power connections

6. Mainboard or Printhead Failure

If all wiring and contamination issues are ruled out, the remaining possibilities may involve deeper hardware problems such as:

• A failing mainboard

• A shorted printhead

• A damaged carriage board

Unfortunately, once board-level components begin to fail, replacement parts or deeper diagnostics may be required.

Addressing printer issues can be complicated because many of the problems involve hands-on inspection and testing. Because of this, we're not able to provide remote troubleshooting, repair guidance, or step-by-step diagnostic support. However, we do offer in-person evaluation and repair services through our diagnostic facility: BCH Printer Repair Service (https://bchtechnologies.com/printer-repair-service).

Due to high demand, repairs are handled on a first-come, first-served basis, and it may take a few weeks before we can accept a printer for drop-off. Our services are structured to repair either the entire printer or specific components, with clear instructions provided on how to proceed. That said, we understand that our repair rates may not be the most economical option. For that reason, we strongly encourage exploring self-help resources online.

A great place to start is YouTube or our channel homepage: BCH Technologies YouTube Channel (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the right side of the menu bar to find videos related to your specific issue. I receive dozens of questions every day asking whether a video exists for a particular repair topic. After producing videos for more than nine years, it's difficult to remember every single one, so using YouTube's search function is the fastest method. YouTube may also suggest helpful videos from other creators that can guide you through similar repairs.

Thanks again for reaching out and for supporting our channel and community. Your questions help us continue improving the resources we provide to printer users everywhere.