How to Install the Epson Carriage Scale Timing Encoder Strip – Does Orientation Matter?

Question:

My Epson L1390 recently received a new encoder strip, and I noticed something interesting: The numbers on the original encoder strip are to the right and inverted. I've followed the steps to install it, but my printer slams when the carriage moves.

I had hoped that replacing the encoder strip would resolve the problem, but it didn’t. How the encoder strip is oriented impacts how the printer runs.

Answer:

Does Encoder Strip Orientation Matter?

Another interesting quirk with Epson printers is the orientation of the numbers due to the encoder strip. According to Epson's official service manual, note the arrow on the encoder strip, which should point up when installed. Keen observers will note that, except for the Epsin L1390 factory-installed encoder strips, all the numbers are upside-down in the "standard" orientation.

So, what does this mean?

If your original strip is upside down, it came from the Epson factory that way.

If your replacement strip is oriented “correctly” (according to the manual), but the problem persists, orientation is not at fault.

I’ve noticed that many repair shops attempt to “right” this by adding it as the manual prescribes, but the fact that it’s in at all does not affect the printer's performance.

Bottom Line:

The numbers or marks on the encoder strip can point in either direction and should not affect printer functionality. If your printer is still banging, the problem is probably somewhere else.

It might get wings: Why Is the Printer Slamming After Replacing the Encoder Strip?

Here are the most common reasons your printer is slamming the carriage after replacing the encoder strip — and how to resolve it:

A. Encoder strip misalignment

If the strip is installed but slightly off, the sensor can’t read it correctly, leading to erratic carriage movement.

✅ How to Fix It:

Press the strip entirely into the encoder sensor(found on the printhead carriage).

Confirm that the strip is secured in both mounting slots to the left and right side of the printer.

Re-tension the strip. The encoder strip should be tight but not so tight that it compromises the housing. Slackening will cause erroneous readings, which can lead to carriage slamming.

B. Encoder sensor dirty or defective

The encoder sensor is a small optical sensor on the carriage unit that reads the encoder strip. Dirty or faulty encoder sensors are standard, causing violent movements because the printer cannot read the strip properly.

✅ How to Fix It:

Clean the sensor window with a lint-free cloth, or a Q-tip with isopropyl alcohol.

Check the sensor for wear and loose connections. When a sensor fails, sometimes the only fix is to replace the carriage unit.

C. Calibration Problems in Firmware or Software

Sometimes, the printer must be re-calibrated if a new encoder strip is installed. Hardware checks only go so far; a hardware reset or manual alignment should be performed if slamming persists.

✅ How to Fix It:

Shared Solutions for Lexmark Printer Not Printing: Power cycle the printer. Please turn it off, disconnect the power cord for a few minutes, and then turn it back on.

Perform a factory reset — This restores sensor calibrations and other settings.

If the problem continues, consult Epson’s service mode software to perform encoder sensor alignment tests.

Is the Problem Something Else?

If the above steps don’t resolve the slamming issue, you might want to look at these components:

Carriage belt tension — Erratic movement can result from a loose or misaligned belt.

Carriage rail lubrication – If the rail is dry or has debris, clean and lightly lubricate.

Defective motherboard (CSIC Board): If nothing above has worked, the mainboard may be faulty, sending incorrect signals to the carriage.

Final Thoughts and Next Steps

It is not the orientation of the encoder strip numbers that is the problem—Epson printers frequently arrive from the factory with strips installed upside down. The problem sounds like an alignment issue, encoder sensor, or mechanical part.

✅ Recommended Steps:

Encoder strip alignment re-engineer

Clean the encoder sensor

If necessary, reset the printer firmware

check carriage motion and belt tension

If problems persist, you may have a faulty encoder sensor or motherboard that will need replacing.

Help with Printer Troubleshooting.

Unfortunately, printer repairs usually require hands-on troubleshooting. While we can guide you through the process, we cannot offer comprehensive troubleshooting remotely. 

We work on a first-come, first-served basis in response to high demand, so getting to your printer might take a while. Detailed instructions are given for both whole printers and parts that need repair. That said, we understand that we are not the cheapest option, so we strongly recommend looking into DIY troubleshooting.

For more support, visit our YouTube Channel: BCH Technologies YouTube Channel. ----------Use the search icon (🔍) next to "About" to search for your specific videos related to encoder strip replacement, printer slamming issues, carriage troubleshooting, etc.

A Parting Thank You and Call to Action

We truly appreciate you reaching out! Troubleshooting printers can be frustrating, especially when installing new parts doesn’t fix the immediate issue. I hope this guide will help you identify the actual root cause of the slamming issue, and that you will get your Epson L1390 back up and running.

Let me know if there are new developments or further questions. Happy repairing!