Epson ET-8550 DTF Keeps Rebooting - Causes and Fixes for Power Cycling Issues

Question:

My Epson ET-8550 converted for DTF printing keeps rebooting without showing any error messages. This started after I tried unclogging the printhead and worked on the ink tubes. Could this be related to the printhead, ink flow, or did I possibly damage the mainboard? I'm located in Conroe, Texas, so I can't bring it in easily for repair.

Answer:

Why the Epson ET-8550 May Keep Rebooting

When an Epson ET-8550 (or any EcoTank model) starts power cycling repeatedly with no visible error code, it usually points to one of three possible causes:

1. Electrical short in the printhead or carriage assembly
   During cleaning or disassembly, a small amount of moisture, ink, or cleaning solution may have reached the printhead's electrical contacts. The ET-8550's printhead uses high-frequency piezo drivers that are very sensitive to conductivity. If any cleaning fluid or ink bridges the fine pins on the printhead's data cable, the printer may immediately reboot as a self-protection mechanism to prevent further damage.

   • Fix: Remove power, disconnect the printhead cable carefully, and allow both the cable and the printhead connector to dry completely (24-48 hours in a warm, dry environment). Do not use alcohol or solvents on these contacts.

   • If you have access to a multimeter, check continuity between the printhead's pins and ground; any short circuit indicates a damaged head or cable.

2. Ink or fluid damage to the mainboard (logic board)
   Since you mentioned working with ink tubes, it's possible a small leak occurred near the mainboard area. Even a few drops of conductive cleaning fluid can cause intermittent shorts. The printer firmware then continuously reboots as it fails initialization.

   • Fix: Unplug the printer, open the side panel, and inspect the mainboard visually for ink residue or corrosion. Gently clean the area using a lint-free cloth and isopropyl alcohol (99% preferred). Allow it to dry thoroughly before powering the printer back on.

3. Firmware failure or corrupted memory state
   Sometimes after a severe short or power interruption, the printer's internal firmware enters a boot loop.

   • Fix: Perform a hard reset: unplug the printer, press and hold the Power button for 60 seconds, then reconnect power while continuing to hold the button for 10 more seconds.

   • If the printer still restarts endlessly, it may require a firmware reflash using Epson's service program (available to authorized repair facilities).

Determining If the Printhead Is at Fault

If the issue began immediately after working on the printhead or ink system, the printhead itself is the most likely cause. A damaged internal coil or liquid short can trigger the power loop. You can test this safely:

1. Disconnect the printhead cable from the carriage board.

2. Power on the printer without the printhead connected.

   • If the printer stays on and shows an error like "Printhead not installed", that confirms the printhead is shorted.

   • If it still reboots, then the fault is likely on the mainboard or carriage board.

If the printhead is confirmed shorted, replacing or professionally repairing it is the only long-term fix. BCH Technologies offers a Printhead Repair Service for Epson models, which includes full disassembly, electrical testing, and nozzle-level restoration. You can learn more about this process at our Printhead Repair Service page (https://bchtechnologies.com/printer-repair-service).

Preventive Tips for Future Maintenance

• Always disconnect the printer from power before handling ink tubes or removing the printhead.

• Avoid allowing cleaning fluid or ink to reach the flat ribbon cables or metal contacts.

• When flushing lines, use gentle suction from the capping station rather than direct pressure on the printhead ports.

• If you must perform multiple cleanings, let the printer rest between cycles to prevent overheating internal components.

Addressing printer issues can be complex because these problems often require hands-on testing and precise inspection. Unfortunately, we can't provide remote repair or one-on-one troubleshooting. However, we do offer in-person evaluations and repairs through our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). Please note that our repair service runs on a first-come, first-served basis and can take a few weeks due to demand. We handle full printer repairs or specific part restorations, with clear service options and pricing.

If you prefer a DIY approach, we encourage you to explore repair guides on YouTube-especially on our BCH Technologies Channel (https://youtube.com/@bchtechnologies). Use the search icon next to "About" to find tutorials specific to your printer model. You may also discover helpful videos from other experts in the printing community.

Thank you again for reaching out and for supporting BCH Technologies. We appreciate your trust and dedication to maintaining your printer, and we're always here to help you make informed, careful repair decisions.