Unable to Solve the "Device Descriptor Request Failed" Error After Changing Mainboard

Question:
I have a printer where I've recently swapped out the mainboard, but I am still running into the USB device error: "Device Descriptor Request Failed." I've installed new drivers on both PCs (Windows 11 and Windows 10) and used two different cables, but the issue persists. I've scoured the internet for hours for a solution, and I'm still lost. My only problem is that the L1800 printer cable cover was broken, but I want to fix this error before anything else. What am I missing?
 
Answer:
We appreciate your reaching out to us at BCH Technologies, and we sincerely apologize for the delay. In particular, we understand that having your printer malfunction (especially when you've been quite productive) can be the biggest headache ever. We want to ensure you know that we take your concerns seriously and will strive to provide the most thorough and clear guidance possible. We could not do this without your interest and support, especially on our YouTube channel(https://youtube.com/@bchtechnologies), allowing us to develop our skills further.
 
Understanding the Issue
Device Descriptor Request Failed error is a standard USB communication issue when the Operating System fails to identify the attached device. A few possible causes you need to treat based on your description:
 
Mainboard Quality: You said you had the mainboard swapped out with a Grade A board from Epson's distributor. This guarantees a quality part, so the board is unlikely to be faulty. But the nuances of incompatibility and setup might still matter.
 
Driver Pre-installation: In some cases, pre-installing the printer driver will solve this problem. Could you make sure you get the most updated drivers for your exact printer model from Epson's site? To install the driver, do the following steps:

• You can start the installer and follow the prompts until it tells you to connect the printer.
• You can only connect the printer with a USB cable if prompted. This enables the installation software to pair the hardware with the drivers correctly.

USB Port and Cable Considerations: 
Given that you've tried different PCs and cables, it is worth confirming the following:

• Please don't use a USB 3.0/3.1 port; you can go directly to a USB 2.0 port. Some printers do not support newer USB standards.
• Never use USB hubs or USB extension cables that can introduce signal degradation.
• Could you check the USB cable's connectors and wire for any visible defects?

Device Manager Reset:
Sometimes, the error is due to a conflict in the Device Manager. To reset:

• Press the Windows button, type in Device Manager, and then click on Device Manager.
• Under "Universal Serial Bus controllers," look for "Unknown USB Device (Device Descriptor Request Failed)."
• Right-click the entry and click "Uninstall device."
• Try restarting your computer and then reconnecting it. This should help Windows detect it and reinstall it.

Firmware Compatibility: Ensure the printer's firmware corresponds to the new mainboard. A mismatch in firmware can prevent communication in some cases. Please review the board's documentation to verify or update firmware.
 
Solving the Cable Cover Problem
We're sorry to learn the cable cover was damaged. The printer doesn't have to work, but if you would like to discuss options for a replacement, we would be happy to do so. Our support team will need to help you directly.
 
Handling printer-related issues is not always straightforward since most problems are hands-on. So, we cannot recommend remote troubleshooting, suggesting, or printer repairs. We provide an in-person evaluation and repair service through our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). The service is subject to availability and operates on a first-come, first-served basis due to the high demand. So it may take a few weeks for us to get your printer to drop it off." We have processes in place, whether for a complete repair of your printer or a specific part. But we admit that our rates are not the cheapest. So we very strongly suggest you do it yourself through online research. Find YouTube videos or go to the homepage and type "BCH" in the search engine on the right beside "About" in the menu bar (https://youtube.com/@bchtechnologies). I get dozens of questions a day about videos for specific topics. Having made videos for over nine years, It's hard to remember every single one. Hence, you can get maximum benefit from the search feature on YouTube. YouTube may also recommend relevant videos from other channels that may help you.
Once again, thank you for contacting us and for your patience as we worked to address your concerns. If you have more questions or need more help, please don't hesitate to get in touch. I appreciate your support!