Troubleshooting Epson WF-7610 Power Failure: Fixing Mainboard and Power Supply Issues

Question

I have an Epson WF-7610 printer. One of the two 2A fuses blew on the power supply board, and after replacing the fuse, the printer still won’t power on. The 5-wire power plug shows 42 volts on two pins, while the other three are grounds. Before the fuse issue, I noticed a red LED glowing on the sensor board behind the main board for a few seconds when plugging in the AC power cord, but now that the power supply is repaired, the red LED doesn’t light up. F1 on the CC97 board is good, and I’ve tried two CC97 boards, both showing the same issue. What other components could be causing the problem? I appreciate any help you can provide.

Answer:

Thank you so much for reaching out to us, Vance, and I apologize for not getting back to you sooner. I completely understand the urgency of getting your printer back up and running, but I wanted to ensure I gave your question the careful attention it deserves. We appreciate your support and engagement at BCH Technologies, primarily through our YouTube channel (https://youtube.com/@bchtechnologies). Your input helps us refine our technical knowledge, benefiting the repair community.
Let's get into the detailed solution for your Epson WF-7610 power issue.

Potential Causes of the Problem

It sounds like you’ve done great by replacing the 2A fuse, checking the voltages, and observing the red LED on the sensor board. However, the fact that both CC97 boards exhibit the same problem indicates that there may be deeper issues with the mainboard or the power supply.
Here are some possible causes and steps to investigate:

1. Mainboard Damage

One of the most likely causes is damage to the mainboard. If components like capacitors or voltage regulators on the mainboard are faulty, the printer may not power on despite the good fuse. Inspect the mainboard for any signs of burning, swelling, or leaking components. Swollen capacitors are a common culprit when a device fails to power on.

2. Faulty Components on the Mainboard

Even with F1 being good on both CC97 boards, critical components like MOSFETs, voltage regulators, or capacitors could still be at fault. I recommend testing each element with a multimeter to ensure they function correctly. A faulty voltage regulator, for example, might cause power delivery issues across the board.

3. Sensor Board Communication Issue

The fact that the red LED no longer lights up could indicate a connection or communication problem between the sensor board and the mainboard. It’s essential to inspect the cables connecting these two boards to make sure there are no damaged or loose connections. A weak or broken signal might prevent the sensor board from functioning as expected, which, in turn, could prevent the printer from powering on.

4. Power Supply Problems

Double-check the power supply’s output voltage, particularly across all relevant pins. While the 42V reading is correct, underlying issues, such as inconsistent power delivery, may still exist. A thorough check of all voltage outputs might reveal hidden faults preventing the printer from powering.

5. Test the Transistors

The red LED you mentioned is likely connected to the photo sensor for the paper feed (PF). I suggest testing the Infineon transistors marked as QF5 and QF6 on the mainboard. Transistors play a crucial role in regulating power flow, and a faulty one can cause your printer to behave as described. Test these transistors first before moving on to capacitors and other components.

6. Use an IR Camera for Component Testing

If you can access an infrared (IR) camera, you can efficiently diagnose faulty components by looking for abnormal hotspots. Here’s how to do it:

• Safety Precautions: Always use proper ESD protection and avoid touching components while the board is powered. Ensure all power connections are secure and safe.
• Set Up for Testing: Place the mainboard on a non-conductive surface and connect only the essential components needed to power the board. Let the board run for a few minutes to reach a stable state.
• Capture Baseline Image: Use the IR camera to capture a baseline thermal image of the board, identifying any standard heat patterns.
• Identify Hotspots: Look for components that are hotter than expected, such as ICs, capacitors, or voltage regulators. Overheating components often indicate shorts or faulty parts, likely causing the power-up issue.
• Follow-Up Testing: Once you’ve identified potential problem areas, use a multimeter to check voltages and test for faulty parts. After replacing damaged components, run another IR scan to ensure everything functions as expected.

This method is very effective for spotting defective components and is widely used in diagnosing mainboard failures.

Generic Troubleshooting Note

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. Therefore, we cannot provide remote troubleshooting, suggestions, or support for printer repairs. We offer in-person evaluation and repair services through our local diagnostic facility, which you can learn more about here (https://bchtechnologies.com/printer-repair-service). Given the high demand for our services, we operate on a first-come, first-served basis, and it may take a few weeks before we can assess your printer.
Our services include repairing the entire printer or specific parts, and we provide clear instructions for mail-in or local drop-off services. However, we understand that our rates may not be the most economical option. That’s why we encourage customers to take advantage of self-help resources. Our YouTube channel (https://youtube.com/@bchtechnologies) is an excellent starting point, and you can search for specific videos using the search bar next to the "About" section. Additionally, YouTube’s search engine may suggest other helpful videos from different channels.
 
Thank you again for your patience and support, and I hope this helps you resolve the issue with your Epson WF-7610 printer!