Troubleshooting Epson ET-8550 CJ20 Main Board: Understanding Capacitor Failures and Possible Fixes

Question:
I followed your video and bought a GME capacitor DCR & ESR tester. I found two capacitors in the red and two in the yellow range on my Epson ET-8550 CJ20 main board. Have you seen these capacitors malfunctioning before, and could they also damage an IC at the same time? Would replacing them fix the issue if no fuses are blown but the printer remains dead? Do you supply these surface-mounted capacitors? The affected ones are labeled C815, C816, C834, and C833, but I can't determine their values visually.

Answer:

Now, regarding your question: finding multiple capacitors-such as C815, C816, C833, and C834-testing in the red or yellow range on the CJ20 main board is unusual. In most cases, when a printer's main board experiences several failed capacitors simultaneously, it suggests that the problem may extend deeper into the circuit, possibly reaching the integrated circuits (ICs). This could occur due to a power surge, overvoltage, or reversed polarity incident, which can overload and weaken several components at once.

When electrolytic or ceramic capacitors fail, they can either short or lose their capacitance, disrupting voltage stabilization on the board. Unfortunately, if the board has sustained extensive electrical damage, some ICs may also have been affected. Many of these ICs are proprietary Epson components with no public datasheets available, making diagnostics and replacements challenging even for experienced technicians.

Replacing the bad capacitors is certainly worth trying, especially if no fuses have blown. However, please keep in mind that while replacing the capacitors might restore part of the circuit, it may not completely revive the printer if one or more ICs are already fried. As for sourcing, BCH Technologies currently does not supply individual surface-mounted capacitors for these printer boards. Your best option would be to use a donor board from another CJ20 or purchase capacitors with matching values and voltage ratings from reputable electronic suppliers like Digi-Key or Mouser.

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 (https://bchtechnologies.com/printer-repair-service) via our local diagnostic facility. Given the high demand, we operate on a first-come, first-served basis, so it might take a few weeks before we can get your printer in for drop-off. Our services are structured to repair either the entire printer or specific parts, with clear instructions on how to proceed. However, we acknowledge that our rates aren't the most economical. Therefore, we highly recommend exploring self-help options through online resources. You can start by checking YouTube, or visiting our YouTube channel homepage (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the right-hand side of the menu bar to locate specific videos. Since we've created videos over the past nine years, searching directly on YouTube will help you find the most relevant guides faster.

Thank you again for reaching out and for your continued support of BCH Technologies. Your engagement encourages us to keep sharing detailed repair insights and helping the printer repair community grow.