Why Epson L1390 DTF Printers Show Cartridge Recognition Errors or Print in the Opposite Direction After Mainboard Replacement

Question

I have two Epson L1390-based DTF printers, one COLORESUN and one Procolored. After replacing the motherboards, both printers are giving different problems even though they are the same L1390 model and appear to use the same connectors.

One printer gives an error saying it does not recognize the ink cartridges. The other printer starts printing in the opposite direction, from left to right instead of the normal direction. The replacement motherboards were purchased from AliExpress stores. Why can these errors happen with new or used L1390 motherboards, and what can I do to repair the printers?

Answer

For the Epson L1390, the first important thing to understand is that there is usually no true "new" L1390 mainboard available anymore in the normal aftermarket. Many boards sold online as "new" are actually refurbished, pulled from used machines, modified, region-converted, or reprogrammed boards. Some may work, but many are not fully tested under DTF conditions. That is especially true when buying from marketplaces such as AliExpress, where the seller may not know the exact firmware condition, EEPROM data, printer region, cartridge system compatibility, or whether the board was previously altered.

Even though the Epson L1390, L1800, 1390, 1430, and related models may look very similar and may share many connector styles, that does not mean every mainboard is electrically, logically, or firmware-compatible with every converted DTF printer. A connector fitting into the socket only tells us the cable physically fits. It does not guarantee that the board firmware, EEPROM information, cartridge recognition circuit, CR motor control, encoder logic, or printer configuration data are correct.

For the first printer, where the board gives an ink cartridge recognition error, the issue is likely related to the CSIC system. CSIC stands for Customer Serviceable Ink Cartridge chip. This is the chip-recognition system that allows the printer to detect the cartridges or, in many DTF conversions, the chip board or chipless/override system being used.

If the printer reports that it does not recognize the ink cartridges, possible causes include a malfunctioning CSIC override board, a bad cartridge chip board, a damaged CSIC cable, a poor connection at the CSIC socket, or a mainboard-side failure in the circuit that reads the cartridge chips. In DTF printers, this becomes more complicated because many machines are modified to use refillable cartridges, external ink systems, CISS systems, dampers, chipless firmware, or third-party CSIC adapters. A replacement motherboard may not behave the same way as the original board if the firmware region or cartridge configuration is different.

The first thing I would check is the CSIC board and its cable. Make sure the cable is fully seated, not reversed, not cracked, and not contaminated with ink. Even a small amount of ink, corrosion, or dried cleaning solution around the CSIC contacts can interrupt communication. Also inspect the socket on the motherboard where the CSIC cable plugs in. If that socket is loose, lifted, cracked, or missing a pin, the printer may act as if no cartridges are installed even if the cartridges and chips are good.

If the printer uses a chipless solution, refillable cartridge chips, or a DTF cartridge bypass board, the replacement mainboard may not match the original chip configuration. For example, a board from a different region may expect a different cartridge chip series. A board that has been reset or reprogrammed may no longer match the chipless activation or cartridge detection setup. In that case, the printer may show cartridge recognition errors even though the mechanical parts are fine.

For the second printer, where the printer begins printing in the opposite direction, that usually points more toward corrupted or mismatched EEPROM data rather than a simple cable problem. The EEPROM stores important printer configuration information, calibration data, region settings, print direction behavior, model identity, and other adjustment values. If the EEPROM is corrupted, cloned incorrectly, copied from the wrong model, or written with bad data, the printer can behave strangely even if the board powers on and accepts commands.

A printer printing in the wrong direction can happen when the mainboard does not correctly interpret the carriage movement, encoder information, motor phase control, or model-specific configuration. The carriage may physically move, but the logic controlling print timing and direction may be wrong. In a normal Epson system, the board must know exactly where the carriage is, which direction it is moving, and when to fire the nozzles. If that data is wrong, the printer can print misaligned, mirrored, shifted, or in the wrong pass direction.

I would suspect the EEPROM on that second board. It may have been corrupted before you received it, or it may have been programmed with data from a different model or configuration. Some sellers take used boards from scrap printers and resell them without properly restoring the EEPROM or confirming the model-specific settings. Others may flash generic data that lets the printer power on but does not preserve the correct adjustment values. This can cause unusual behavior such as incorrect carriage direction, wrong paper feed calibration, abnormal print alignment, or strange motor movement.

Because both of these problems happened after replacing the motherboards, I would not assume the printers themselves are the root cause right away. The mainboards are the common factor. With aftermarket L1390 boards, especially ones purchased from unknown sources, the problem can be the board itself, the board's EEPROM, the cartridge recognition circuit, or a mismatch between the board and the printer's DTF conversion setup.

Here is how I would approach the repair.

First, compare the original board and replacement board carefully. Check the exact board number, connector layout, firmware label, chip locations, and any visible modifications. Do not rely only on the fact that the connectors look the same. If the original board still partially works, it may be useful as a reference.

Second, inspect every cable before blaming the new board completely. The flat flexible cables must be clean, straight, and inserted evenly. Pay special attention to the CSIC cable, printhead cable, CR encoder sensor cable, carriage motor cable, and any DTF conversion wiring. A reversed or damaged cable can cause confusing symptoms and can sometimes damage the board.

Third, for the cartridge recognition error, focus on the CSIC path. Test with known-good cartridge chips or a known-good CSIC/chip board if available. Inspect the cartridge chip contacts and the CSIC socket on the motherboard. If the printer uses a chipless or bypass system, verify whether that system is compatible with the replacement mainboard. If the CSIC socket or circuit on the replacement board is defective, the practical repair may be to replace the socket, repair the circuit, transfer parts from the original board, or obtain a better-tested board.

Fourth, for the reverse-direction printing issue, focus on EEPROM and calibration data. If you have the correct tools and experience, the EEPROM from the original working board may need to be read, backed up, and written to the replacement board. However, this must be done carefully because copying the wrong data or writing to the wrong chip can make the situation worse. In some cases, an Epson adjustment program may correct certain calibration values, but if the EEPROM data itself is badly mismatched or corrupted, software adjustment alone may not fully solve the problem.

Fifth, make sure the replacement board is truly for the L1390 configuration you are using. The L1390 is closely related to other Epson models, but DTF printers are often converted, modified, or rebranded. COLORESUN and Procolored may use the same base Epson engine, but the way the machine was converted can differ. One printer may use a different chip board, ink system, firmware setup, waste ink reset configuration, or cable routing than the other. That means one replacement board may not automatically work correctly in both machines.

Sixth, be careful about repeatedly testing questionable boards. A defective mainboard can damage a printhead, and a damaged printhead can damage a mainboard. If there is a short in the printhead cable, ink contamination near the printhead terminals, or a blown transistor/FET on the board, swapping parts back and forth can spread the damage. Before installing another board, inspect the printhead cable and printhead connectors for ink, burns, corrosion, or bent contacts.

For future replacements, I strongly recommend getting L1390 boards only from a trusted source that can confirm the board has been tested, is compatible with your printer configuration, and has proper EEPROM data. Cheap boards may look attractive, but if the EEPROM is wrong, the CSIC circuit is damaged, or the seller has no way to test the board under real printing conditions, the repair can become more expensive than buying a properly tested board in the first place.

In your specific case, my best guess is this: the first replacement board likely has a problem with the CSIC overwrite/bypass system, the CSIC socket, or the cartridge recognition circuit. The second replacement board likely has corrupted or mismatched EEPROM data, causing incorrect print direction behavior. Both issues are consistent with used, refurbished, improperly programmed, or poorly tested L1390 mainboards.

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

Thank you again for reaching out and for supporting our work. I hope this gives you a clearer idea of why the two L1390 motherboards are producing different errors and what areas you should inspect before replacing more parts.