Epson WF-3640 Error Code 0x9A After Printhead Replacement – What It Means and How to Fix It

Question:

I recently replaced the printhead on my Epson WF-3640 printer with a new one, but now I'm getting error code 0x9A. What does this mean, and how can I fix it?

Answer:

What Does Error Code 0x9A Mean?

Error 0x9A on Epson printers is generally classified as a mechanical or hardware malfunction. It’s a non-specific error, but in cases involving recent hardware work—like a printhead replacement—it often points to one of the following:

1. Blown Printhead Fuse on the Mainboard:
   Epson printers include a tiny surface-mounted fuse on the mainboard that helps regulate power to the printhead. If the new printhead draws too much current or is incompatible (even slightly), it can blow that fuse. Once blown, the printer loses its ability to communicate or power the printhead, resulting in a 0x9A error.

2. Mainboard Damage or Circuit Error:
   During the replacement process,, the motherboard can become damaged especially if static discharge or power was not fully isolated, This might result in a persistent 0x9A code, even if the new printhead is functional.

3. Incorrect or Faulty Printhead Installation:
   If the ribbon cables are not seated properly,or the printhead is not fully compatible with the WF-3640, t fault response. can occur Double-check cable seating and part compatibility.

Troubleshooting Steps:

Here are a few things you can try:

• Double-check all ribbon cable connections. Make sure they are securely and adequately inserted without bends or contamination.

• Inspect the mainboard fuses (uthis sually requires magnification and some experience with surface-mount electronics). If tafuse is blown, you may be able to replace it if you’re comfortable with micro soldering.

• Reinstall the old printhead (assuming it still works) and check if the 0x9A error disappears. If it does, the issue likely lies with the new printhead or its compatibility.

• In worst-case scenarios, replacing the mainboard may be necessary if it has suffered a circuit failure.

Remember that Epson printers are designed to be sensitive to unauthorized part replacements, especially with non-OEM components. Sometimes, even a compatible printhead can trip an internal protection mechanism if tolerances aren’t exact.

Printer hardware issues—especially component-level faults—can be challenging to resolve remotely. As such, we don’t provide step-by-step remote support for repairs or upgrades. However, we do offer in-person diagnostic and repair services (https://bchtechnologies.com/printer-repair-service) at our North Carolina facility. Please note that due to high volume, we operate on a first come, first served basis, and there may be a delay before we can accept your printer. Our services include full-printer diagnostics and part-level repairs, but our rates may not be the most budget-friendly. That’s why we encourage users to research and attempt basic fixes first. A great place to start is our YouTube channel homepage (https://youtube.com/@bchtechnologies). Use the search icon next to the "About" tab to look up relevant video content by keyword. This approach is often the fastest way to find targeted troubleshooting steps—even if the video comes from another reliable channel.