Epson ET-8550 Won't Power On After Cleaning: Moisture and Fuse Concerns

Question:
I have two Epson ET-8550 printers that will not power on. I suspect moisture may have gotten inside the print head during an external cleaning. Could moisture damage the print head? Is it possible to flush the print head and circuit board with alcohol, allow it to fully dry, and then reuse it? Also, could a blown fuse be the worst-case scenario?

Answer:

Moisture and the Print Head

Moisture inside the print head or its circuitry is one of the most damaging situations for an Epson ET-8550. The print head contains sensitive nozzles and delicate electronic contacts. If water or cleaning fluid reaches these electronics, it can cause short circuits, corrosion, or permanent failure. Once the board is shorted, it is very difficult to revive. Even if it seems to work after drying, corrosion may set in over time and cause failure weeks later.

Alcohol Flushing Considerations

Flushing a circuit board or print head with isopropyl alcohol (99% preferred) can help displace water and speed up drying, but it is not a guaranteed solution. The concern is that alcohol may not reach under all the chips or inside ribbon cable sockets, where trapped moisture can still linger. Additionally, scrubbing or applying too much alcohol may loosen adhesives or coatings. If you try this method, the part must be allowed to dry completely-ideally for several days in a dry, warm environment, or with the help of a desiccant or dehumidifier.

Power Failure and Fuses

When a printer won't power on after a moisture event, it could indeed be a blown fuse on the main board or power board. Epson printers have tiny surface-mounted fuses that protect the circuitry from shorts. Replacing these requires advanced soldering skills and careful testing with a multimeter. Unfortunately, if the fuse blew due to a short in the print head, replacing the fuse without fixing the underlying problem will likely cause it to blow again.

Best-Case and Worst-Case Scenarios

• Best case: The printer powers back on after thorough drying, and the fuse remains intact.

• Moderate case: A fuse replacement restores power, but the print head still functions.

• Worst case: The print head and/or main board is permanently damaged from the moisture.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. So, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We offer an in-person evaluation and repair service via our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). Given the high demand, we operate on a first-come, first-served basis, and it may take a few weeks before we can get to your printer once it is dropped off. Our services cover both full printer repair and part-specific repairs, with clear instructions on how to proceed. However, we recognize that our rates are not always the most economical. For that reason, we recommend exploring self-help options through online resources. A great place to start is by visiting our YouTube channel homepage (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the menu bar to look for videos covering your issue. With nearly a decade of content, it's hard to recall each video offhand, but YouTube's search function is the most efficient way to locate the right guide. You may also discover related videos from other creators that could be helpful.

Thank you again for your patience and for bringing your question to us. We truly value your support and engagement.