Identifying the Correct EEPROM Chip on Epson CG36 Mainboards

Question:
I suspect my printer issue may be linked to a corrupted EEPROM. I understand that I should be looking for a Winbond SOP8 chip on the Epson CG36 mainboard, but I’m having trouble identifying it. There are several 8-pin ICs on the board (IC3, IC4, IC8, IC10, IC11), yet none have the Winbond logo or the type numbers listed on the BCH Technologies website. Could you clarify which of these ICs is the EEPROM chip, or provide a circuit reference to help identify the correct one?

Answer:

On the Epson CG36 mainboard, the EEPROM chips are most likely to be IC3 and IC4. Epson has historically used multiple vendors for its memory components. In earlier models like the Epson WF-3640, Epson alternated between Micron and Winbond chips, sometimes within the same production batch. This practice created confusion, as half of the boards shipped with Micron chips and the other half with different alternatives.

Epson often employs a dual-chip system for memory management. In such setups, one chip stores usage data (e.g., print counts, error logs, and ink consumption records), while another chip may handle firmware or calibration data. In your case, the two Micron chips on IC3 and IC4 likely fulfill this role, with differing memory sizes.

It’s also worth noting that Epson boards sometimes include an unmounted slot for firmware storage. This isn’t unusual—it suggests Epson designed flexibility for using different chip configurations during manufacturing. That detail further supports the conclusion that IC3 and IC4 are indeed the EEPROM/firmware chips for this model.

When troubleshooting or replacing these chips, remember:

• EEPROMs are typically marked with small alphanumeric codes rather than transparent brand logos. Absence of the Winbond logo doesn’t rule them out.

• If using a programmer or tester, compare dump data between IC3 and IC4 to determine which stores critical usage data.

• Be cautious when reworking or desoldering, since excessive heat can corrupt the data layer.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. That’s why we aren’t able to provide remote troubleshooting or repair support. However, BCH Technologies offers in-person evaluations at our printer repair service center (https://bchtechnologies.com/printer-repair-service). We work on a first-come, first-served basis, and depending on demand, it may take a few weeks before your printer can be processed. Our services are structured to cover entire printer repairs or targeted part replacements with clear next steps. That said, we recognize our pricing may not be the most economical, so we also encourage self-repair efforts. A good starting point is our YouTube channel (https://youtube.com/@bchtechnologies). Use the search feature on the channel page to look for specific repair topics—this is the quickest way to find relevant videos out of the hundreds we’ve published over the last nine years.

Thank you again for your question and for being part of our community. Your support allows us to keep sharing knowledge and helping printer owners worldwide.