How to Fix a Dim or Black Display Screen on Epson ET-8550 Printers

Question:
After replacing the F2 fuse, the error code disappeared and the printer powered up normally. However, the screen remained black. With the help of a headlamp and a flashlight, we could faintly see the display, navigate the menus, and perform test prints and head cleanings. The printer functions correctly and prints in full color, but the display remains extremely dim. Adjusting the brightness did not resolve the issue, and I'm concerned that the display may fail completely. Are there any videos or guides on repairing or replacing parts related to display communication failure or display driver failure?

Answer:

Based on your description, the printer is fully functional except for the LCD panel visibility, which points to one of two likely issues:

1. Display Communication Failure

The screen relies on a set of flat flexible cables (FFC cables) to transmit data between the mainboard and the LCD. If one of these cables is loose, damaged, or has developed a weak connection, the display may still technically work but appear dim or distorted. For the Epson ET-8550, the LCD cable is bundled with the scanner cables in a three-cable set. We have a replacement kit available here: ET-8550 Scanner and LCD Cable Set (https://bchtechnologies.com/products/ffc-cable-for-epson-ecotank-et-8550-scanner-3-cable-combo-et8550?_pos=2&_sid=ce9015379&_ss=r).

When replacing these cables, ensure that each connector is seated properly and locked into place. Even a slightly misaligned or loose connection can cause the screen to behave as you've described.

2. Display Driver Failure or Backlight Issue

If replacing or reseating the cables does not solve the issue, the problem could be with the LCD driver circuit or the backlight inside the display itself. In such cases, replacing the entire control panel (LCD screen assembly) is usually the most reliable solution. We carry used replacement panels for the ET-8550 here: Epson ET-8550 Control Panel (https://bchtechnologies.com/products/epson-et-8550-control-panel-used-no-return?_pos=3&_sid=d35b58536&_ss=r).

Given that you can faintly see the display under direct light, it's likely the backlight is failing rather than the image processor itself. This is a common issue and often requires a panel swap rather than a simple repair.

3. Video Resources

While I do not currently have a dedicated video specifically for the ET-8550 display replacement, my video on scanner cable replacement for the same model demonstrates how to access and replace the FFC cables, which includes the LCD cable. This can be a valuable guide for tackling the communication-related side of the issue.

Addressing printer problems like this can be complex and requires physical access to delicate parts. For that reason, we cannot provide remote step-by-step troubleshooting or repair guarantees. However, we do offer an in-person diagnostic and repair service through our local repair facility (https://bchtechnologies.com/printer-repair-service). Please note that service is first-come, first-served, and it may take several weeks before we can process your printer. While our repair services are comprehensive, we recognize that they may not be the most budget-friendly option. This is why we encourage exploring self-help solutions first, especially through online resources. A good starting point is our YouTube channel homepage (https://youtube.com/@bchtechnologies). You can use the search icon next to "About" on the right-hand side of the menu bar to quickly locate relevant videos. With nearly a decade of content, searching directly often yields faster results than browsing.

Thank you again for your patience and support. We appreciate your trust in BCH Technologies, and we hope this information helps guide you toward a lasting solution for your printer.