Epson EcoTank ET-7550 LCD Panel Buttons Not Working - Troubleshooting and Fixes

Question:
On my Epson EcoTank ET-7550, three buttons on the control panel (up, down, and OK) don't respond. I assumed the whole control panel was faulty, so I replaced it with a new one, but the problem still remains. Could this be caused by something else inside the printer? What's the likely reason that only some buttons don't work?

Answer:

Now, regarding your Epson ET-7550 where only certain buttons on the control panel don't work:

1. Why Replacing the Panel Didn't Fix the Problem

Since you've already swapped out the control panel and the same buttons (up, down, OK) are still unresponsive, the fault is unlikely to be with the panel hardware itself. Instead, the issue is most likely deeper in the printer's circuitry-specifically, the connection pathway between the panel and the main board.

2. Common Causes of Button Failures

• Flat Flexible Cable (FFC) Issues:
  The control panel connects to the printer's main board using a flat ribbon cable. If this cable is damaged, misaligned, or has dirty contacts, signals from certain buttons won't register. Even one pin not making proper contact can cause only some buttons to fail.

• Main Board Input Faults:
  The buttons send signals through dedicated input lines on the main board. If the IC (integrated circuit) responsible for scanning the button matrix is damaged, only certain buttons will stop working. This can happen due to static discharge, moisture, or even age-related component wear.

• Shared Circuit Paths:
  On most Epson control panels, buttons are arranged in a matrix configuration (rows and columns). If one line in the matrix isn't being read, it can cause exactly the type of issue you're seeing-several buttons in the same "row" or "column" stop responding, while the others still function normally.

3. Troubleshooting Steps to Consider

• Inspect and Clean the Ribbon Cable: Remove the FFC cable, inspect the pins for oxidation or damage, and clean with isopropyl alcohol. Reseat carefully, ensuring it's fully inserted and aligned.

• Check Continuity with a Multimeter: If you're comfortable, test continuity along the suspect pins in the FFC cable. A break in one trace could explain why only some buttons are dead.

• Examine the Main Board Connector: Look for bent pins, cracked solder joints, or heat damage around the panel connector on the main board.

• Board-Level Repair or Replacement: If the cable and connector check out, the issue likely resides in the main board circuitry. Unfortunately, that usually requires either replacing the main board or attempting advanced board-level repair.

Addressing printer issues like this can be complicated because they often involve board-level electronics and physical testing. For this reason, we're not able to provide remote repair or troubleshooting beyond general guidance. However, we do offer in-person diagnostic and repair services through our local facility (https://bchtechnologies.com/printer-repair-service). Due to high demand, repairs are scheduled on a first-come, first-served basis, and it may take a few weeks before we can begin work on your printer. Our services include both complete printer repairs and targeted part replacements, with clear instructions for customers. Still, we recognize our pricing may not always be the most economical, so we also encourage you to make use of online resources. A great place to start is our YouTube channel homepage (https://youtube.com/@bchtechnologies). You can use the search function next to the "About" tab to locate relevant tutorials. With nine years of videos available, this is the fastest way to find what you need, and YouTube may also suggest additional repair content from other creators that could be useful.

Thank you again for your support and for reaching out with such a detailed question. We truly appreciate the trust you place in BCH Technologies and are glad to help you navigate these challenging printer problems.