How to Test XP600 and ET8550 Printheads Using a Multimeter

Understanding the Importance of Printhead Testing

When working with printers such as the Epson XP600 and ET8550, ensuring that the printhead is functioning properly is essential. These components are responsible for transferring ink accurately to the paper, and any malfunction can lead to misprints, missing colors, or even hardware damage. Before installing a new or refurbished printhead, it's wise to test it using a multimeter.

This guide explains how to test XP600 and ET8550 printheads step-by-step using a multimeter. Both models use similar testing methods because their printheads share identical configurations. If you're setting up or troubleshooting a printer, this process will help you verify the condition of your printhead and avoid potential short circuits or installation issues.

Tools and Materials You'll Need

Before starting, prepare the following items:

• A digital multimeter with a diode testing function.

• An XP600 printhead cable (29-pin) or an ET8550 cable (which splits into two smaller cables).

• A clean, static-free workspace.

• The pin reference chart, available for download from BCH Technologies' website.

BCH Technologies offers replacement printhead cables and reference sheets for both XP600 and ET8550 printheads. You can visit their site at bchtechnologies.com and search for the SKU mentioned in the video or documentation.

Identifying Printhead Pins

Printheads like the XP600 and ET8550 have 29 pins arranged in a single row. Understanding pin orientation is crucial before connecting your testing cables.

To begin, place the printhead face down with the nozzle plate facing the sky. This position helps in aligning your cables properly. When looking at the printhead this way:

• The leftmost pin is Pin 1.

• The rightmost pin is Pin 29.

If you're using an XP600 cable, it connects directly to the printhead. The silver side of the cable should face you, and the pins should point upward. If you're using an ET8550 cable, note that it splits into two smaller cables - one for the left side (pins 1-14) and another for the right side (pins 16-29). The middle pin (Pin 15) is located on the printhead itself and is not measured through the cable.

Setting Up the Multimeter

Set your multimeter to diode testing mode. The diode function is typically represented by a small arrow symbol. This setting allows you to measure the voltage drop between two pins, helping you detect short or open circuits.

Next, connect the red probe of the multimeter to the pin labeled in the reference chart (for instance, Pin 8 on the left cable), and use the black probe to test the remaining pins one by one.

Remember these rules while testing:

• A valid reading typically falls within ±20% of the expected range. Ideally, it should stay within ±10%.

• If the multimeter shows "OL" (Open Loop), it means the two pins are not connected, which is normal for certain pairs.

• If you get a continuous connection reading (short) where it shouldn't be, it indicates a problem with the printhead.

Performing the Printhead Test

Let's start by testing the left-side cable (Pins 1-14). For example:

• Pin 1: 571 (good)

• Pin 2: OL (open)

• Pin 3: 572 (good)

• Pin 4: OL (open)

• Pin 5: 571 (good)

• Pin 6: OL (open)

• Pin 7: 498 (within range)

Continue this process through all 14 pins. If all readings fall within the expected range, the left side of the printhead is functioning correctly.

Now, move to the right-side cable (Pins 16-29). The procedure is identical. For instance:

• Pin 1 (of right cable): 572 (good)

• Pin 2: OL (open)

• Pin 3: 571 (good)

• Pin 5: 572 (good)

• Pin 7: 569 (good)

• Pin 8: 4 (open, expected)

At the end of testing, if the results show consistent readings with only a few open loops where expected, your printhead is likely in good working condition.

Interpreting the Results

During testing, it's normal to encounter "OL" values on certain pins. This does not always indicate a defect. However, you should be alert for:

• Zero resistance or continuous tone - indicates a shorted circuit.

• Unusually high or low readings - may point to a failed nozzle or damaged connection.

• Random inconsistencies across corresponding pins - often a sign of internal damage or corrosion.

If one or more pins show suspicious readings, compare them with the reference chart from BCH Technologies. For example, in one test, Pin 7 on the ET8550 showed a reading of 14, which was far outside the normal range, indicating a fault.

Identifying these issues early helps prevent damage to your printer's mainboard when the printhead is installed.

Using BCH Technologies Resources

BCH Technologies provides valuable tools and reference materials for printhead testing and maintenance. Their website offers:

• Downloadable reference charts for XP600 and ET8550 printheads.

• Replacement cables and connectors designed specifically for these models.

• Instructional videos that demonstrate real-world printhead testing and repair procedures.

You can easily find the resources by searching for the product SKU listed in their documentation or by browsing through the printhead section of their website.

And for those who prefer visual learning, we have a video below that walks you through every step of this process - from cable connection to interpreting multimeter readings.

Troubleshooting Common Printhead Problems

Even with proper testing, printheads may exhibit other issues over time. Here are a few common scenarios and how to address them:

1. Uneven or missing color output
This often points to clogged nozzles or dried ink. Use cleaning solutions and run printhead cleaning cycles before replacing the unit.

2. Repeated short circuit readings
If multiple pins read as shorted, the printhead likely suffered electrical damage. Replacing it is usually the safest solution.

3. Intermittent readings
Fluctuating multimeter results may stem from loose cable connections or corrosion on the contact pads. Clean the contacts gently with isopropyl alcohol and retest.

4. Consistent "OL" results on all pins
This could indicate a disconnected cable or a faulty ribbon. Check for continuity on the cable itself before assuming the printhead is defective.

By incorporating these troubleshooting practices, you can maintain your printers efficiently and prevent unnecessary replacements.

Enhancing Your Printer Maintenance Routine

Testing printheads before installation is only one part of comprehensive printer maintenance. Pair this step with other good habits:

• Regularly clean your printer's capping station and wiper blade.

• Use high-quality inks that are compatible with your printhead model.

• Perform routine nozzle checks and cleaning cycles.

• Store your printers in a controlled environment to minimize moisture and dust buildup.

These simple measures can significantly extend the lifespan of your printhead and improve print quality over time.

Final Thoughts

Testing your XP600 or ET8550 printhead using a multimeter is a straightforward yet powerful diagnostic step. By following the pin-counting guide, setting your multimeter correctly, and referencing the data from BCH Technologies, you can confidently determine the condition of your printhead before installation.

This simple process not only saves you time and money but also protects your printer from preventable damage. And if you want to see exactly how it's done, check out the video below for a step-by-step visual guide from BCH Technologies.