Epson ET-8550 Scanner Error 100017: Why the Carriage Overruns the Right Side

Question:

My Epson ET-8550 scanner moves to the right, hits the side, and lifts upward. The printer then shows error 100017. Is a stop piece missing?

Answer:

Thank you for contacting BCH Technologies, and I apologize for the delayed reply. Printer and scanner problems are urgent, but we want to give you a careful, detailed answer before suggesting a part. Thank you for supporting BCH and our YouTube channel.

The right-side contact itself can be part of scanner initialization on the ET-8550. The carriage should detect that position and stop. Continuing to push until it climbs upward is abnormal. Error 100017 is described in the service information as a contact-detection distance being exceeded. That points to failed detection or drive movement, but the symptom alone does not identify the failed component. It does not prove that a separate stop block or switch is missing.

The CR carriage right-stop spring on the product page is for the printhead carriage, not the scanner. Do not install that part to solve a scanner fault. Possible causes to check include a scanner carriage that has lifted out of its guide, damaged or disengaged drive gears, a belt or guide obstruction, an encoder-reading problem, or a loose or damaged scanner flat-flex cable. The CIS module, scanner housing, or mainboard can also be involved. These are possibilities, not confirmed diagnoses.

Turn off and unplug the printer before inspection. Do not keep powering it up while the carriage jumps, and do not force the scanner back into place. Look for a visible obstruction, cracked housing, displaced carriage or guide, or damaged drive teeth at the right side. If you have the experience to open the scanner safely, photograph connections before disconnecting anything and inspect the scanner cables for creases, corrosion, or loose seating. Do not reconnect a cable with power attached. The service notes identify the scanner CIS cable at mainboard connector CN70 and the scanner motor cable at CN72; connector work should follow the exact model service procedure.

If the carriage is visibly out of its guide, the drive slips, or error 100017 returns after safe visual checks, have a technician diagnose the scanner drive, encoder, cable path, and CIS before replacing parts. Board-level diagnosis may be needed if those parts are sound. BCH Technologies can discuss repair service if you share a short video of the movement, a photo of the printer label, and what happened just before the fault. Search the BCH Technologies YouTube channel [https://youtube.com/@bchtechnologies] for ET-8550 scanner, error 100017, and scanner carriage repair.