Epson L1800 DTF Printer USB Not Recognized | How to Fix it

Question: I just changed the thermistors for my Epson L1800 DTF printer. Powering it on after reassembly, I forgot to plug the USB into my PC first. The USB cable may have contact with the metal housing of the DTF printer when it tries to connect the USB cable. Now, my computer displays the error "Device Descriptor Request Failed," and it does not recognize the printer. I've reinstalled drivers and run troubleshooters, but the printer isn't connecting. Can you help?
 
Answer: Sorry for the delay in responding. We know that printer problems can be urgent. We assure you we're taking this matter seriously and handling it with the appropriate care. Thank you for your engagement and support at BCH Technologies. Please do check out our YouTube page (https://youtube.com/@bchtechnologies). Your feedback helps us continue improving our knowledge and assist others dealing with similar problems.
 
Understanding the Issue
However, your printer's USB port runs at low voltage, so the shorting or inadvertent connection of the cables should not cause a great deal of damage. The internal USB connects straight to the printer's PCB (Printed Circuit Board), reducing the chance of shorts destroying the USB port or board.
With your setup of the L1800 DTF printer, your USB connection likely has a few changes if interfaced, as you describe. The USB port is commonly routed to the back of the printer for access, so an internal cable connects the port to the mainboard. This rerouted setup can be bypassed by connecting the USB cable directly to the mainboard to ensure no issues with the intermediate cable.
 
Diagnosing the Problem
The error message "Device Descriptor Request Failed" generally indicates that your USB device (printer) is not talking to your PC. This can be caused by:
Firmware Corruption:

• This can happen if the printer's firmware is corrupted, causing the mainboard not to initiate communication with your computer.

USB Cable or Connection Problems:

• Flawed cables, loosened cables, or interference can cause the communication to fail.

Driver Conflicts:

• Therefore, reinstalling drivers may not completely fix the problem if residual conflicts or incomplete configurations remain.

 
Potential Fixes
Direct USB Connection:

• Take out the rerouted USB cable and plug your USB into the printer's mainboard directly. This helps test whether the external cable or port is defective.

Inspect Firmware Status:

• If the firmware on your printer is corrupted, re-uploading the firmware may solve the problem. This step would be relatively easy if the USB connection were still working, which, unfortunately, it is not. The killer is that you would require a hardware programmer to reflash the firmware to the board.

Check the USB Cable and Port:

• Try the USB data cable on another device to check if it works correctly.
• Examine the printer's USB port for signs of physical damage or debris that could interfere with a good connection.

Try a Different PC or OS:

• Avoid PC-specific problems by connecting the printer to another computer.
• You can also check whether the problem exists using another operating system like Linux.

Professional Repair Services:

• For businesses that cannot fix the problem themselves, consider professional repair services to fix the printer and restore its functionality. This can involve reprogramming the firmware or swapping out corrupted parts.

 
Additional Resources
Despite printers being very hands-on, diagnosing and fixing problems can prove challenging. We are sorry, but we cannot offer remote diagnostics or repairs. While we do not repair printers directly, we provide a diagnostic service, specifically (https://bchtechnologies.com/printer-repair-service) at our local facility. Our services operate on a first-come, first-served basis due to high demand, and it may be several weeks before we can place your printer in service. We repair whole printers or individual parts with what to do next. Our rates may not be the lowest, but we recommend starting with self-help materials.
Visit our YouTube Channel for further help (Join: https://youtube.com/@bchtechnologies). Now, you can search videos related to your problem using the search bar just across the "About" section. YouTube's algorithm might also recommend helpful content from other creators.
Again, thank you for contacting us and supporting BCH Technologies. We hope this information is helpful in resolving your problem. If you have any more questions, please let us know!