How to Troubleshoot a Dead Control Panel and Carriage Slam on an Epson 1390 or L1800 Printer

Question:
My Epson 1390/L1800 printer powers on, but the control panel doesn’t respond at all. Before this issue, the print carriage was slamming into the side of the frame. I’ve replaced several components including the main board, encoder strip, power supply (though it might be the wrong one), print carriage, and FFC cables—but nothing has worked. I even have the wiring diagrams for the board connectors. Can you help me figure out what’s going wrong and point me toward the correct parts or videos?

Answer:
Thank you so much for contacting us, and first, I want to sincerely apologize for the delay in getting back to you. We understand how frustrating it is when your printer is down, especially after you've put so much effort into fixing it. All printer issues are urgent, and we want to treat each one with the detailed attention it deserves. Here at BCH Technologies, we truly appreciate your support—especially if you’ve engaged with our YouTube channel (https://youtube.com/@bchtechnologies). Your feedback helps us keep improving and sharing more helpful content with the printer community.

Now, onto the issues you're facing. From your description, it sounds like your Epson 1390 or L1800 printer is experiencing a combination of hardware-level failures, possibly from mismatched parts or incorrect power delivery. Here's a breakdown of the most likely causes and fixes based on your symptoms:

🔌 Power Board and Voltage Supply Issues

Even if the printer powers on partially, if the power board isn’t delivering the correct voltages (typically 24V and 5V rails), the control panel will appear dead and the rest of the printer won’t initialize. Using a multimeter to test voltage output is critical here. If the power supply was replaced with a wrong model—even if the connector fits—the voltage may be incorrect and prevent proper startup. Always verify output specs before swapping in power boards.

🧠 Mainboard and Control Panel Compatibility

You mentioned replacing the mainboard, but if it's not matched with the correct firmware and control panel for your specific model (1390 vs. L1800), you can end up with silent communication failure. For instance, a panel from an Epson L1800 may not function properly if connected to a 1390 board or a variant with incompatible firmware. If the panel is receiving voltage but still shows no response (no LEDs, no button feedback), this could be the cause.

⚙️ Carriage Slamming Against Frame

When the carriage slams into the side of the printer, it's often due to an issue with the encoder strip or carriage sensor. The encoder strip might be:

• Installed backward (check for readable markings facing the right direction)

• Missing entirely

• Dirty or scratched
  Alternatively, the timing (position) sensor on the print carriage might be damaged. If the printer can’t determine carriage position, it will hit its stop point during initialization. Also, when you install a new mainboard, it may need proper alignment or reset procedures to sync with the printer’s mechanical position.

🔧 FFC Cable Issues

Flat flexible cables (FFC) are sensitive, and even one misaligned pin or reversed cable can cause complete failure. We’ve seen printers appear "dead" simply due to:

• Reversed cable installation (blue tab facing the wrong way)

• Damaged or crimped cables

• Incorrect cable length (too long or too short causing signal degradation or stress on connectors)
  It’s worth removing and carefully reinstalling each cable, ensuring there are no bent pins or misalignments.

✅ Recommendation

After replacing so many individual parts, your best next step would be to obtain a verified and matched set: a power board, mainboard, and control panel all from the same model and ideally the same printer. This will eliminate any potential firmware or hardware mismatches. We can assist you with sourcing the correct matched sets if needed.

Once those matched components are installed and all cable orientations and connections are verified, the printer has a much better chance of recovering. We’ve seen units in worse shape bounce back once everything was properly aligned.

Addressing printer issues can be tricky due to the hands-on nature of the work. That’s why we’re unable to offer remote troubleshooting or repair suggestions in real-time. However, we do offer an in-person printer diagnostic and repair service (https://bchtechnologies.com/printer-repair-service). Please note that we operate on a first-come, first-served basis, and depending on the current volume, there may be a wait time of several weeks before we can begin work on your printer. We can handle full printer repairs or specific part replacements with clear service options available. That said, we understand our service rates may not be the most budget-friendly. So, if you’d like to explore a DIY route, we highly encourage you to browse our YouTube channel homepage (https://youtube.com/@bchtechnologies) and use the search bar near the "About" tab to find content relevant to your issue. With over nine years of videos, using keywords like “Epson 1390 board replacement” or “carriage slam fix” can help you quickly locate potential solutions.

Thanks again for your patience and for reaching out to BCH Technologies. We’re rooting for you to get your printer back online soon—don’t hesitate to contact us again if you need help sourcing parts or verifying compatibility.