Epson ET-8550 Printing Slow, Jamming, and 00031 Error After Drag Chain Installation

Question:
I have an Epson ET-8550 and recently installed a drag chain. Since then, printing has become very slow, and the printer sometimes jams. I am not sure whether the problem is related to the motor. Right now, the only way I can keep it going is to restart the printer, and when the printhead moves all the way to the left, I have to gently push it to prevent an error. Could you advise what part might need replacement, such as the CR motor, PF motor, or something else?

Answer:

Based on what you described, this does not immediately point to only one part such as the CR motor or PF motor. The fact that you need to gently push the printhead when it reaches the far left in order to avoid error code 00031 is a very important clue. That suggests the printer is having trouble correctly determining carriage position, carriage load, or carriage motion timing at that point in travel. In other words, the issue may involve the carriage system as a whole rather than just one motor.

Let us break this down.

The 00031 error on Epson printers is commonly associated with a carriage movement fault. In practical terms, that means the printer expected the carriage to move or home correctly, but something interfered with that process. Possible causes include mechanical resistance, contamination on the encoder system, a weak or overloaded carriage motor, drag from an add-on such as the drag chain, cable interference, sensor reading problems, or in some cases a control-board or firmware issue.

Since your symptoms started after installing the drag chain, the first thing to inspect is whether the drag chain is creating extra resistance or misalignment. Even if it looks fine visually, a drag chain can still cause subtle problems if:

• it is too tight at one end of travel,

• it pulls the carriage upward or sideways,

• it adds extra load near the far-left parking position,

• the tubing or cable bundle inside it is too stiff,

• it interferes with the carriage reaching its proper home point,

• or it causes the carriage cable/ink lines to rub against the frame.

Because you mentioned the carriage must be pushed when it reaches the far left, I would start there before assuming the motor is bad. The printer should be able to complete that movement smoothly on its own. If it cannot, the extra drag may be enough to trigger 00031.

The next thing to check is the CR system, meaning the Carriage Return motor, carriage belt, carriage rail, encoder strip, and CR sensor.

A worn or weak CR motor can absolutely cause slow carriage travel, hesitation, or difficulty reaching the left side properly. If the printer has to fight more resistance than normal because of the drag chain, a marginal CR motor may start showing symptoms that were not obvious before. That would fit your report of slower printing. The CR motor is more relevant here than the PF motor. The PF motor is the paper feed motor, so it is usually responsible for moving paper, not for moving the printhead carriage side to side. If your main symptoms are slow carriage travel, jamming during carriage movement, or needing to help the printhead reach home, I would suspect the CR side first, not the PF side.

You should also inspect the carriage belt. A loose belt, worn belt teeth, or belt contamination can cause hesitation, inaccurate carriage positioning, and noise. Likewise, the carriage rail should be clean and lightly lubricated with an appropriate lubricant. If the rail is dry, sticky, or contaminated with ink mist and dust, the carriage can bind more noticeably at the ends of travel.

Another very important item is the CR encoder strip-sometimes called the carriage scale-and the CR sensor that reads it. If the strip has ink mist, grease, fingerprints, or dust on it, the printer can misread the carriage position and throw movement-related errors, including 00031. A dirty encoder strip may also make carriage motion seem erratic or slower because the firmware keeps correcting movement based on bad readings. The strip should be inspected carefully and cleaned gently using the proper method. The sensor itself should also be checked for dust or contamination. If you installed the drag chain and worked around that area, it is possible the strip was touched or slightly displaced during the process.

Now, regarding firmware and memory corruption: this is less common than a mechanical cause, but it is still possible, especially since you noted the carriage must be pushed at a very specific point. If the printer logic is giving incorrect homing or movement instructions, the problem can sometimes appear to be mechanical when it is actually electronic. In some cases, updating or rolling back firmware may allow the system to use a different memory area and temporarily bypass a corrupted section. However, firmware work carries risk. If the corruption is in a critical stored area, reflashing can worsen the problem or leave the printer nonfunctional. In the most severe cases, the real fix is not simply a firmware reload but replacement of the EEPROM chip on the mainboard, followed by reprogramming with a known good firmware image. That is a much more advanced board-level repair and should only be considered after eliminating the far more likely mechanical and sensor-related causes.

So in order of probability, I would check the following:

1. Drag chain installation and cable/tube movement
   Make sure the chain moves freely across the full carriage range with no tight spots, pulling, twisting, or binding at the far left.

2. CR encoder strip and CR sensor
   Clean and inspect both carefully. A contaminated strip can cause incorrect carriage position readings and trigger 00031.

3. Carriage path mechanics
   Check the carriage rail, belt, and any obstructions. Make sure nothing is rubbing or adding resistance.

4. CR motor condition
   If the printer remains slow and weak in carriage movement after the above checks, the CR motor becomes a strong suspect. A worn motor can struggle under the extra load introduced by a drag chain.

5. Mainboard / firmware / EEPROM issue
   Consider this only after the mechanical and sensor causes have been ruled out.

Based on your description, I would not start by replacing the PF motor. The PF motor would be more suspect if you were having paper advance errors, skewing, paper not feeding correctly, or feed-related jams without carriage symptoms. Your symptoms are centered much more around the carriage side.

You may also find it useful to review this industrial high-torque CR motor upgrade for Epson ET-8550, L1800, R1390, 1390, and DTF printers [https://bchtechnologies.com/products/industrial-high-torque-cr-motor-upgrade-for-epson-et-8550-l1800-r1390-1390-dtf-printers?_pos=1&_sid=dc6bb1261&_ss=r], especially if you confirm that the carriage is under higher-than-normal load or the original motor is losing torque.

Printer problems like this can be complicated because they are so hands-on in nature. For that reason, we are not able to provide remote troubleshooting, repair suggestions, or technical support for printer repairs beyond general guidance. We do offer an in-person evaluation and repair service through our local diagnostic facility [https://bchtechnologies.com/printer-repair-service]. Because demand is high, we handle repairs on a first-come, first-served basis, and it may take a few weeks before we are able to receive your printer for drop-off. Our services are organized around either complete printer repair or repair of specific assemblies, with clear instructions on how to proceed. That said, we understand our service rates may not be the lowest option available, so we strongly encourage self-help through online research first. A good place to begin is YouTube, including our BCH Technologies YouTube homepage [https://youtube.com/@bchtechnologies]. You can use the search icon next to "About" on the right side of the menu bar to look for videos on your exact topic. I receive many questions every day asking whether we have covered a certain repair before, and after making videos for many years, it is difficult to remember every single one. Using YouTube's search function is usually the fastest and most effective method, and it may also surface helpful videos from other creators.

Thank you again for reaching out to us and for your continued support. We sincerely appreciate your trust in BCH Technologies, and we hope this gives you a clearer direction on what to inspect first.