Epson RX640 Fatal Error 0x50: Cannot Seek CR Home Position, Cartridge Recognition, and Refillable Cartridge Options

Question

I used the Epson Adjustment Program for my Epson RX640 printer, and it showed a fatal error message: 0x50 - Cannot seek CR home position. I was not sure what this meant.

After checking a database recommendation, I switched the printer off, unplugged it, and then connected it again. After doing this, the error message started to change, then disappeared, and the printer is now printing normally.

I also tried using auto-reset ink tanks. The printer only shows that the magenta cartridge is not a genuine Epson cartridge, with the option to accept using it.

Does the 0x50 fatal error mean the printer still has a current problem? Also, would you recommend using original Epson cartridges that can be refilled and reset? If so, what is the best way to refill and reset them, and what type of resetter should be used?

Answer

For your Epson RX640, the 0x50 fatal error with the message "Cannot seek CR home position" usually points to a problem related to the CR system, meaning the carriage return system. The carriage is the part that holds the ink cartridges and printhead and moves left and right across the printer.

However, in your case, there is one very important point: the error shown in the Epson Adjustment Program is not always the current active error. Many Epson adjustment programs display the last recorded fatal error stored in the printer's memory. So, if the printer is now printing normally after being powered off, unplugged, and restarted, the 0x50 error may simply be the last fatal error that happened previously, not necessarily a problem that is still happening right now.

The message "Cannot seek CR home position" means that, at some point, the printer tried to move the carriage back to its home position and could not confirm that it arrived correctly. This can happen for several reasons, including:

The carriage may have been physically blocked by paper, dried ink, a foreign object, or a mispositioned cartridge. Even a small obstruction can prevent the carriage from moving freely.

The carriage lock or parking station may have been stuck. On older Epson models, dried ink around the capping station or parking area can make the printhead carriage harder to release.

The CR encoder strip may have had contamination on it. This is the clear plastic strip running behind the carriage. If it has ink mist, grease, dust, or fingerprints on it, the carriage sensor may lose track of the carriage position.

The carriage motor may have experienced temporary resistance or overload. If the motor cannot move the carriage smoothly, the printer may register a fatal error.

The printer may have had a momentary startup-positioning failure. Sometimes unplugging the printer and allowing it to reset mechanically can clear a temporary error.

Since your printer now prints normally, I would not immediately assume that the printer still has a serious mechanical fault. I would treat the 0x50 as a warning history entry unless the printer starts showing symptoms again, such as grinding noises, carriage movement failure, repeated startup errors, or the carriage stopping in the wrong place.

If the error returns, I would check the carriage path first. With the printer unplugged, inspect the inside for paper scraps, broken plastic, dried ink buildup, or anything blocking the carriage. Then check whether the carriage can move smoothly by hand after it is unlocked. Do not force it if it is parked and locked. Also inspect the clear encoder strip behind the carriage. If it is dirty, clean it very gently with a lint-free cloth slightly dampened with distilled water. Avoid harsh solvents because the encoder markings can be damaged.

Regarding the cartridge message, the warning that the magenta cartridge is not a genuine Epson cartridge is separate from the 0x50 CR home position error. A non-genuine cartridge warning means the printer recognizes that the cartridge chip is not Epson-original. In many Epson printers, you can accept the warning and continue printing. If the printer gives you the option to proceed and the ink level reads properly, this is usually not a fatal issue.

As for whether you should use original Epson cartridges that can be refilled and reset, the answer depends on what you want to achieve.

Original Epson cartridges are usually built with better physical tolerances than many aftermarket cartridges, so they may fit more reliably. However, not all original Epson cartridges are easy to refill and reset. Many genuine Epson cartridges use chips that are not designed for unlimited reuse. Some can be reset with the correct chip resetter, while others may become difficult or impractical to reuse depending on the cartridge generation and chip type.

For older Epson printers like the RX640, refillable cartridges with auto-reset chips are often more convenient than trying to refill original cartridges. A good-quality refillable cartridge set normally has fill plugs, air vents, and resettable chips. The chip may reset when the cartridge is removed and reinserted, or when the printer reports it as empty, depending on the chip design. The advantage is convenience. The disadvantage is that cheaper auto-reset cartridges may create recognition problems, such as the non-genuine warning you are seeing, or occasional cartridge-not-recognized messages.

If you want to refill original Epson cartridges, you would need a resetter that specifically supports the cartridge chip series used by the Epson RX640 cartridges. It is important not to buy a generic Epson resetter without checking compatibility, because Epson chip resetters are not universal. The resetter must match the cartridge family and chip type. If the resetter is not compatible, it may do nothing even though it physically touches the chip contacts.

For refilling, the general process is to remove the cartridge, identify the correct fill port or create a refill access point if required, inject the correct dye ink slowly, seal the cartridge properly, and then reset the chip before reinstalling it. You also need to avoid overfilling, because excess ink can leak into the cartridge bay or contaminate the printhead area. After refilling, let the cartridge sit so air bubbles can settle before printing. Air bubbles are a common cause of missing colors or intermittent nozzle dropout after refilling.

For your situation, since the printer is currently printing and only complains about the magenta cartridge being non-genuine, I would not change everything immediately. I would first continue testing the current setup. If the magenta cartridge prints correctly and the printer allows you to accept the warning, you may be fine. If the magenta cartridge starts disappearing, showing "not recognized," or causing repeated cartridge errors, then replace that cartridge or chip first rather than replacing the whole system.

In short, the 0x50 "Cannot seek CR home position" message likely reflects a previous carriage-positioning event stored in the adjustment program, especially since the printer is now working. It does not necessarily mean the printer currently has an active fatal error. The non-genuine magenta warning is a cartridge chip recognition issue and is probably unrelated to the 0x50 carriage error. For refilling, a good refillable cartridge set with reliable chips is usually easier than refilling original Epson cartridges, but if you choose original cartridges, make sure the chip resetter is specifically compatible with the RX640 cartridge type.

Addressing printer issues can be a complicated affair because many of these problems require hands-on inspection. For that reason, we are not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do 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 receive your printer for drop-off. Our services are structured to repair either the whole printer or specific parts, with clear instructions on how to proceed. However, we understand that our rates may not be the most economical option for every situation. Therefore, we highly recommend using self-help resources through online research. A good place to start is YouTube, including our channel homepage: BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. You can search for specific videos by using the search icon next to "About" on the right-hand side of the channel menu bar. I receive dozens of questions every day asking for videos on specific topics, and after creating videos for the past nine years, it is difficult to remember every single one. Using YouTube's search function is usually the most efficient method, and YouTube may also recommend helpful videos from other channels.

Thank you again for reaching out and for supporting BCH Technologies. I'm glad to hear that the printer is currently printing again, and I hope this explanation helps you better understand what the 0x50 error and the magenta cartridge warning mean.