Troubleshooting a 1390-Based Model J Printer That Won’t Print – Is the Mainboard the Problem?

Question:
We have a 1390-based Model J printer that still isn’t working. We’ve replaced the ribbon cables and confirmed they are seated correctly, cleaned the capping station, and confirmed ink is being pulled in. The F1 and F2 fuses test fine. Could this be a mainboard issue? Is there a way to test it to rule it out or narrow down the cause?

From what you’ve described—properly reinstalled ribbon cables, a cleaned capping station, visible ink draw, and good F1/F2 fuses—a mainboard (motherboard) issue is indeed a reasonable suspect. In Epson 1390-based printers, the mainboard is responsible for controlling the printhead firing sequence, ink charging, and other core operations. If all mechanical and consumable components are functioning correctly, an electronic fault becomes much more likely.

1. Why the Mainboard Could Be the Culprit

• Printhead driver failure – If the driver IC on the mainboard fails, the printer may power on normally but never send the correct firing signals to the head.

• Voltage regulation issues – The mainboard provides critical voltages to the printhead. If these are absent or unstable, printing will fail.

• Data communication loss – Even with a functioning printhead, damaged data lines or connectors on the board can prevent proper operation.

2. How to Narrow Down a Mainboard Fault

Unfortunately, there’s no single “plug-and-play” diagnostic test for a 1390 mainboard without swapping it with a known good unit. However, you can perform several checks:

1. Visual inspection – Remove the board and check for burn marks, corrosion, or physical damage, especially around the head connector, voltage regulators, and fuse area.

2. Check printhead voltage output – Using a multimeter, measure the voltage at the printhead connector while the printer is attempting to print. You should see roughly 15–20 volts during the firing cycle. If voltage is missing, the mainboard’s power section may be faulty.

3. Test the printhead driver chip – The SOP28 E09A7218A driver IC can fail and should be tested or replaced if faulty. You can find a replacement here (https://bchtechnologies.com/products/sop28-e09a7218a-218a-printer-driver-chip-for-epson-integrated-circuit-ic-l1800-artisan-1430-1390).

4. Use a schematic reference – Having the mainboard schematic will help trace voltages and signals. A reference diagram for the Stylus Photo 1390 is available here (https://bchtechnologies.com/products/reference-for-stylus-photo-1390).

5. Board swap test – If you have access to another working 1390-based printer, temporarily swapping the mainboard is the fastest way to confirm if your board is faulty.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. For that reason, we’re unable to provide remote troubleshooting, suggestions, or direct support for printer repairs. We do offer an in-person evaluation and repair service via our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). Due to high demand, our repairs are handled on a first-come, first-served basis, and it might take a few weeks before we can get to your printer once it’s dropped off. We repair either whole printers or specific parts, with clear instructions for the next steps. While our rates may not be the lowest, we encourage you to explore self-help options first, starting with our YouTube channel (https://youtube.com/@bchtechnologies). Use the search icon next to “About” to quickly locate videos on specific repairs.

Thank you again for your question and for being part of the BCH Technologies community!