Epson L1800 Not Printing on Film? Diagnosing Dual Fuse Blowouts and Printhead Problems

Question:

I have an Epson L1800 (Procolored version) printer that has stopped printing on film. After some testing with a multimeter, I discovered that both the main F1 fuse and the secondary “insurance” fuse are blown. The MOSFETs appear to be functioning properly based on diagnostic diagrams, and I’ve maintained them since purchasing the device in December 2024. Could this point to a faulty printhead? Also, should I keep that secondary fuse when replacing the original one? Lastly, what would it cost if BCH Technologies handled the repair?

Answer:

Thank you for contacting us. Please accept our apologies for the delay in responding to you. We understand how frustrating and time-sensitive printer malfunctions can be. Each issue deserves careful, in-depth attention to provide the best possible guidance. Everyone here at BCH Technologies sincerely appreciates your engagement, especially your support of our YouTube channel (https://youtube.com/@bchtechnologies). Your thoughtful questions and feedback genuinely help us evolve and share better solutions with the printing community.

Now, let’s tackle your questions, fuse by fuse.

The Role of the F1 and “Insurance” Fuse on the Epson L1800

What Procolored (and some other aftermarket vendors) refer to as the “insurance” fuse is not an actual protective backup, but rather a relocation of the F1 fuse to a more accessible position. It’s connected in series or parallel with the original board fuse to avoid removing the mainboard during future replacements. The concept is convenience, not protection.

However, when both fuses blow simultaneously, it typically indicates a deeper electrical issue—most likely a shorted printhead. While it's not always definitive, experience shows that when a printhead draws excessive current, it can burn through both the onboard fuse and the auxiliary “insurance” one.

Your observation that the MOSFETs are functioning correctly is excellent news—that rules out other critical power delivery components. But the fact remains: fuses only blow when something demands more power than it should.

Printhead: The Likely Culprit

Yes, based on your description and our experience, the printhead is a strong suspect. These heads are precision components, but they’re also fragile and susceptible to failure, especially if subjected to power surges, incorrect voltage during head cleaning, moisture exposure, or clogged nozzles that trigger excessive resistance. If you're seeing consistent fuse blowouts after replacing them, we would recommend testing or replacing the printhead before powering up the board again.

Should You Keep the “Insurance” Fuse Setup?

We generally don’t recommend reinstalling the external “insurance” fuse in future repairs. Instead, we suggest turning off the original onboard fuse entirely and soldering a replacement inline fuse with wire in its place. This method not only restores proper circuit protection but also reduces confusion and potential failure points. Once the new fuse is installed correctly, there’s no real advantage to reintroducing the external version—it’s a redundancy that doesn't offer actual protection.

For your specific case, we recommend our dedicated F1/F2 Fuse Replacement for Epson L1800 DTG/DTF Printers (https://bchtechnologies.com/products/f1-f2-fuse-for-epson-l1800-dtg-dtf-printer). It’s designed precisely for this situation and can restore functionality if the fuse is your only point of failure.

Repair Service and Cost Estimate

We offer a flat-rate mainboard repair service for the Epson L1800 and several other models. Our Fast Track Mainboard Repair Service (https://bchtechnologies.com/collections/printer-repair-service/products/fast-track-mainboard-repair-l1800-xp-15000-et-15000-wf-7610-7620-wf-7110-wf-7710-7720-et-8550-et-2720-et-2750printer-mainboard-formatter-board-motherboard-troubleshooting-and-repair) is priced at $75, which includes diagnostics, fuse replacement, and minor board repairs. If deeper issues are discovered, we’ll communicate any additional costs before proceeding.

Addressing printer malfunctions can be quite complex due to the hands-on testing and component-level work required. As such, we're not able to provide remote repairs or detailed diagnostic support. Instead, we offer in-person troubleshooting through our printer repair facility (https://bchtechnologies.com/printer-repair-service). Demand is high, and repairs are conducted on a first-come, first-served basis. Expect a short wait before you can drop off your printer. Our team can work on complete units or individual components, and we’ll provide clear repair instructions once your request is submitted. If our services aren’t within your budget, we strongly suggest self-help options through platforms like YouTube. Our channel homepage (https://youtube.com/@bchtechnologies) is a great place to start—use the search icon near the “About” tab to find the right video quickly. We’ve uploaded hundreds of guides, and YouTube’s algorithm may even point you toward helpful content from other trusted creators.

Thank you again for your kind words, for subscribing to our channel, and for placing your trust in our guidance. We wish you and your Epson L1800 a speedy return to full printing glory!