Epson ET-8550 Grinding Noise After FFC Cable Replacement: Check the CR Encoder Belt and Encoder Sensor

Question

I replaced the FFC cable on my Epson ET-8550 with a replacement cable that was longer than the original OEM cable. I ordered the cable for the ET-8550, and the printer does power on. However, after replacing the cable, the printer carriage runs hard against the left side of the printer near the power button, makes a screeching or grinding noise, and then displays a message telling me to shut off the printer and restart it. Could this still be a paper jam issue, or is something else wrong after the FFC cable replacement?

Answer

Yes, the replacement FFC cable being longer than the original Epson OEM cable is intentional. We made the cable longer on purpose because many ET-8550 DTF, DTG, sublimation, and modified printer setups need extra routing flexibility. A slightly longer FFC cable is not automatically a defect, and it should not by itself cause the carriage to slam into the side of the printer. However, after replacing the FFC cable, it is very easy for another nearby part to get displaced, especially the clear CR encoder strip, also called the carriage encoder belt or timing position strip.

Based on your description, this sounds much more like a CR encoder positioning issue than a regular paper jam. When the printer powers on, the carriage must know where it is located. It does this by reading the clear encoder strip through the CR encoder sensor on the back of the carriage. If the clear encoder strip is outside the sensor slot, dirty, twisted, disconnected, or not passing through the sensor correctly, the printer cannot read the carriage position. As a result, the carriage may move blindly until it hits the side of the printer, creating a loud screeching or grinding noise. The printer then stops and gives a general message telling you to shut off the printer and restart it.

The clear CR encoder strip must be tucked inside the CR encoder sensor. This is the key point. The encoder strip should pass through the small sensor opening on the carriage assembly. If the strip is behind the sensor, in front of the sensor, above it, below it, or resting outside the slot, the printer will lose carriage-position feedback. The motor may still have power and try to move the carriage, but the logic board will not receive the correct location signal, so the carriage may crash into the left side.

This issue often happens during FFC cable replacement because the FFC cable, encoder strip, and carriage area are close together. When removing or installing the cable, the clear encoder strip can accidentally pop out of the sensor. Because the strip is transparent, it can be hard to see unless you use a flashlight and look carefully from the back side of the carriage. Many people focus on the new cable and do not notice that the encoder strip is no longer threaded through the sensor.

To check this, turn the printer off and unplug it first. Do not keep powering it on while it is grinding, because repeated carriage crashes can damage the carriage belt, carriage motor, frame, encoder strip, or sensor. With the printer unplugged, gently move the carriage by hand only if it is not locked. Then inspect the clear strip that runs horizontally behind the carriage. It should be clean, straight, and routed through the encoder sensor on the carriage. The strip should not be hanging loose, folded, scratched, heavily stained with ink, or outside the reader.

If the strip has popped out, carefully guide it back into the CR encoder sensor slot. The sensor is usually a small U-shaped or slotted reader on the carriage. The clear strip needs to sit inside that slot so the sensor can read the fine markings on the strip. Be gentle because the encoder strip can be scratched or stretched. If it becomes contaminated with ink or grease, clean it carefully with a lint-free cloth. Avoid harsh pressure, and avoid pulling it off its spring mounts.

Also check that the FFC cable is not interfering with carriage movement. Since the replacement cable is longer than the original, it must be routed and folded neatly so it does not bow upward, drag across the carriage path, catch the encoder strip, or block the carriage from moving freely. The extra length should be arranged so the carriage can move from side to side without the cable pulling tight or bunching up. A cable that is installed correctly electrically but routed poorly mechanically can still cause movement problems.

A true paper jam usually causes a different kind of symptom. With a paper jam, the printer may try to feed paper, stop during paper movement, or report a jam after detecting resistance in the paper path. What you are describing-carriage running into the left side near the power button, grinding, and then asking to restart-is more consistent with a carriage-position detection problem. The most likely cause after the FFC replacement is that the clear CR encoder strip is not inside the CR encoder sensor.

After confirming the encoder strip is correctly seated, also inspect the following areas:

Make sure the carriage can slide smoothly by hand when the printer is unplugged and unlocked. It should not bind or hit the FFC cable.

Make sure the FFC cable is fully inserted into the printhead and mainboard connectors, with the contacts facing the correct direction.

Make sure the cable is not folded sharply, pinched, or crossing the encoder strip incorrectly.

Make sure the encoder strip is not twisted. The strip must remain flat and pass cleanly through the sensor.

Make sure no tools, screws, ink tubes, dampers, or clips are blocking the carriage path.

Make sure the carriage lock or service station area is not jammed.

If the printer still grinds after the encoder strip is correctly routed, then the next possible causes would be a dirty or damaged CR encoder sensor, a scratched encoder strip, a disconnected carriage motor cable, an obstruction in the carriage path, or a problem created during reassembly. However, from the symptom and timing, the first thing I would check is the clear CR encoder belt/strip and whether it is tucked inside the CR encoder sensor.

Addressing printer issues can be a complicated affair because many printer problems require hands-on inspection and adjustment. For that reason, we are not able to provide remote troubleshooting, repair suggestions, or support for individual printer repairs. We offer an in-person evaluation and repair service through our local diagnostic facility: BCH Technologies Printer Repair Service [https://bchtechnologies.com/printer-repair-service]. Because demand is high, we operate on a first-come, first-served basis, so it may take a few weeks before we can accept your printer for drop-off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we understand that our rates are not the most economical option for every customer. For that reason, we strongly recommend self-help through online research whenever possible. You can start by checking YouTube or visiting our YouTube channel homepage: BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Use the search icon next to "About" on the right-hand side of the menu bar to search for specific videos. I receive dozens of questions every day asking about videos for specific topics. Since we have created videos over the past nine years, it is difficult to remember every single one. YouTube's search function is usually the most efficient way to find the right video, and YouTube may also suggest relevant videos from other channels that could help.

Thank you again for contacting us and for supporting BCH Technologies. In this case, the longer FFC cable is expected, but the clear CR encoder strip must be properly seated inside the CR encoder sensor. That is the first area I would inspect before assuming the problem is a paper jam or a defective cable.