How to Troubleshoot Epson ET-3750 Printhead Issues and Identify Loose Cables

Question:

I recently received an Epson ET-3750 printer from a friend who had trouble getting it to print. Although the printer has plenty of ink, it was left unused for several months. After several power cleaning cycles, my friend gave up and purchased a new printer.

As I reassemble the printer, I’ve noticed a red and black cable that appears disconnected. I’m trying to determine whether this is a signal or data cable and where it should be connected for proper operation.

Additionally, I have an Epson SureColor P800 Inkjet 17-inch printer, which I regularly clean using Bounty paper towels soaked in Windex to absorb excess ink from the printheads. I followed the cleaning procedures on Jose Rodriguez’s YouTube channel (Jose Rodriguez Photo Printing Techie).

If the ET-3750's printhead channel tubes are not clogged, I recommend using the same cleaning method. I have the printhead positioned in the center of the travel and am soaking up excess ink to see if it helps unclog the nozzles.

Could you provide guidance on the red and black cable and whether my cleaning method is appropriate for this printer?

Answer:

1. Identifying the Red and Black Cable in the Epson ET-3750

The red and black cable you found is likely one of the following:

• Carriage Encoder Sensor Cable: This connects to the carriage unit and provides position feedback for the printhead’s movement. If left disconnected, the printer may not register the correct carriage position, causing errors.
• Printhead Power Cable: This cable supplies voltage to the printhead for ink ejection. If this is disconnected, the printhead will not function properly.
  
• Pump Motor or ASF (Automatic Sheet Feeder) Motor Cable: Unplugging could interfere with ink flow during printing if it’s part of the ink pumping system.

Check the mainboard near the printhead assembly to find the correct connection point. Most Epson printers' red and black cables connect to power-related components, such as motors or heating elements in the printhead. If the printer throws an error upon startup, that could also indicate an unplugged essential component.

If you have photos or a service manual, they can provide additional insight. Epson service manuals often label cable connection points.

2. Cleaning the Printhead on the Epson ET-3750

Your Windex and paper towel method is commonly used for piezoelectric inkjet printers like the Epson SureColor P800. However, for the Epson ET-3750, there are some differences to consider:

• Soaking the printhead in the center of the travel position is a good idea because it allows the cleaning solution to dissolve dried ink without interference from the capping station.
• Using Windex is generally safe, but if the clog is severe, a dedicated printhead cleaning solution (such as BCH Cleaning Solution) might be more effective.
• Printhead channel tubes may still be clogged even if you see ink pooling on the paper towel. If power cleaning cycles haven’t resolved the issue, consider gently flushing cleaning solution through the printhead nozzles with a syringe and tubing.

Additional Recommendations

1. Check the Ink Flow System: If the printer had been unused for months, the ink in the tubes may have dried up. If so, air bubbles may prevent proper ink flow to the printhead.
   
2. Run a Nozzle Check: Print a nozzle check pattern before attempting another power cleaning cycle to see which colors are affected. If only one or two channels are blocked, targeted cleaning is more effective than full-system flushing.
3. Inspect the Capping Station: The ET-3750’s capping station (where the printhead rests when idle) contains a sponge that can dry out and fail to keep the printhead hydrated. Cleaning the sponge with distilled water can improve printhead maintenance if the sponge is dirty or dried out.
   

Additional Support for Printer Repairs

Printer troubleshooting often requires hands-on work, and while we do our best to provide guidance, we cannot offer remote troubleshooting or repair support. However, we provide an in-person evaluation and repair service at the BCH Technologies Printer Repair Service, our local diagnostic facility.

Due to high demand, we operate on a first-come, first-served basis, so there may be a wait before your printer can be serviced. Our repair services cover entire printers or specific parts, and we provide clear instructions on how to proceed. However, our rates may not be the most economical option for everyone.

If you prefer a DIY approach, we highly encourage you to check out our YouTube Channel: BCH Technologies YouTube Channel. Use the channel page's search icon (🔍) to find videos related to your issue. Given the number of videos we've created over the past nine years, searching with relevant keywords is the fastest way to find what you need.

Additionally, YouTube’s search function may suggest related videos from other creators that provide helpful solutions.

Thank you again for contacting us. We appreciate your support, and hope this information helps you get your Epson ET-3750 back in working condition. If you have any further questions, feel free to explore our resources. Happy repairing!