How to Safely Install a New Printhead After Electrical Damage: A Guide for A3+ Printer Recovery

Question:

My A3+ printer was likely damaged by a lightning strike, which led the manufacturer to recommend replacing nearly all internal boards. I’ve already replaced the mainboard, control board (with an encoder bypass), the 42V/24V power board, and the white ink circulation motor. After that, the printhead was clogged and wouldn’t print black. I used parts from an Amazon board to restore ink flow, but the printer shut off during the first cleaning cycle. I tested the power board—connected, it outputs zero volts; disconnected, it gives 41V. The manufacturer claims printhead flushing caused damage, but I’m skeptical. After rotating through four mainboards, one finally got the printer to home and start a clean cycle (without a printhead), though it threw a temperature error. The manufacturer blames a shorted head and cable. I now have a new printhead from Kingdom DTF. Is it safe to test the old head first, or could that damage my last good mainboard? Also, can BCH help diagnose or repair the other boards I’ve removed?

Answer:

1. Do Not Use the Old Printhead — Install the New One

Given that you now have only one fully functional mainboard, it’s critical to protect it. If the old printhead is indeed shorted—as the manufacturer suspects—or if the large ribbon cable has internal carbon tracking or micro-corrosion, you risk frying your last good board. A short in the head can reflect voltage spikes into sensitive components, such as FETs and voltage regulators.

Recommendation: Install the new Kingdom DTF printhead, and pair it with a brand-new ribbon cable if there are any stains or discoloration on the old one. Even subtle contamination can arc at high voltages. Don’t take chances here—the cost of another board failure far outweighs a new cable.

2. Power Board Behavior Suggests a Faulty Subsystem

The fact that your 42V/24V power supply outputs zero volts when connected to the small board—but shows 41V when disconnected—strongly suggests:

• A short circuit on the daughter (small) board,

• Or excessive current draw caused by a failing component (like a jammed ink pump or burned capacitor).

Try using a known-good 42V/24V power board, especially if it came from a verified working unit. However, be cautious about design differences—some boards have layout or capacitor value changes that affect current stability. Swapping boards with minor physical mismatches could create erratic behavior or overstress other parts.

3. BCH Can Help Bench Test and Diagnose Your Boards

For the three other mainboards:

• One is visibly burned—this one is unfortunately beyond saving.

• One was new but didn’t function—it may still be viable if the fault was external (e.g., caused by a bad power board).

• One is a wildcard—the "oldest-looking" board that brought partial functionality.

We’d be happy to help you bench test these boards. At BCH, we can check for:

• Voltage rail integrity (3.3V, 5V, and logic-level power),

• Shorted or degraded FETs,

• Faulty diodes, inductors, or blown capacitors,

• Surface contamination or arcing.

Just send the boards to us—we can help determine which ones, if any, can be safely revived.

4. Test Voltage Rails Before Plugging in the New Printhead

Before installing the new head:

• Boot the printer without the printhead installed.

• Use a multimeter to measure the voltage on the printhead supply pins on the board.

• Look for proper voltage (usually 30–42V, depending on the model) and check for ripple or overvoltage conditions.

This step can prevent permanent damage to your new printhead by verifying the board isn’t misbehaving.

5. Send High-Quality Photos for Additional Analysis

You mentioned that you had photos of the boards. Please email them to support@bchtechnologies.com. We’ll review them and check for:

• Signs of heat damage,

• Incorrect component swaps,

• Inconsistent capacitor layouts between revisions,

• Risk of polarity or logic conflicts between different generations of hardware.

Even visual inspection can reveal a lot, especially when comparing against known good configurations.

Final Thoughts

Your situation is a great example of how poor OEM support can force users into a trial-and-error path. That said, you've handled it extremely well—systematically replacing components, verifying connections, and troubleshooting power loss. With that momentum, the best path forward is:

• Protect your last good board by not testing with the old printhead.

• Use a clean ribbon cable.

• Install and test the new printhead only after verifying voltage behavior.

• Send your questionable boards to us—we’ll help you determine what can be salvaged.

Feel free to reach out if you’d like help walking through live voltage tests, capacitor identification, or cable continuity checks. We’re happy to assist where we can.

Dealing with hardware faults in printers can be time-consuming and tricky due to the hands-on diagnostics required. For this reason, we’re unable to provide remote troubleshooting or repair support. However, we do offer in-person evaluation and diagnostics through our printer repair facility (https://bchtechnologies.com/printer-repair-service). Because of high demand, repairs are handled on a first-come, first-served basis, and lead time may be a few weeks. While our service is detailed and methodical, it may not be the most budget-friendly. Therefore, we strongly recommend pursuing self-help first—especially via online videos and tutorials. Start by visiting our YouTube channel homepage (https://youtube.com/@bchtechnologies). You can use the search icon next to the “About” tab to find videos on specific topics. With nine years of content, there’s a good chance the answer is already posted—even if I can’t recall every individual video off-hand.

Thanks again for trusting BCH Technologies. Your persistence in fixing this printer is admirable, and we’re here to help however we can!