Troubleshooting my Melco EMC 10T

The needle is stuck down.

After powering off, unplugging, and rebooting the screen comes on, then goes blank. Prior to this, directly after the problem began, I was receiving a message "Bad Instruction"

I'm worried I might need to replace the circuit board. I feel it could be this because the green light is not coming on. I have another one but I don't want to do that if it's not the issue.

I'm looking for guidance on the fix, or any information anyone might have?

You're dealing with a couple of simultaneous issues on your Melco EMC 10T—both mechanical (needle stuck down) and electrical/software (screen blanking and “Bad Instruction” error, plus no green light). Let's tackle them step by step.

---

Mechanical: Needle Stuck Down — Possible Z-Bind

A Z‑bind is a common cause if the needle becomes stuck down or the presser foot is trapped:

• Use the Emergency Stop to halt the machine.

• Lift the presser foot and slightly rotate the Z‑shaft by hand.

• Verify the presser foot isn’t binding on the Needle Block Clamp. If it is, gently pull the presser foot back and clear the bind.

• In more general cases (not tied to maintenance), follow Melco’s in-depth instructions to:

  • Remove the needle plate if the bind is below that area.

  • Check if the hook basket spins freely (remove the rotary hook if needed).

  • See if the grabber is stuck behind the needle bar.

  • Look for broken needle remnants in the hook and use compressed air to clear debris.

  • If drive studs and reciprocator are misaligned, carefully examine and possibly remove the needle bar to free the bind—though a Melco Certified Technician might be required.

These are mechanical fixes you can try before involving circuit boards.

---

Electrical/Software: “Bad Instruction,” Blank Screen, No Green Light

You mentioned the message “Bad Instruction”, which indicates a fatal error from the CPU—meaning the processor received an invalid or unexpected

Additionally, the blank screen and absence of the green light signal that the main PCB (circuit board) might be failing or not receiving power/control.

Here's what Melco's technical support suggests:

1. Power Cycle: Turn the machine fully off; wait a minute; power it back on—and if needed, repeat. Sometimes this resets internal electronics.

2. Reseat the Ethernet Cable: Ensure the cable connecting the control panel (keypad/display) to the main PCB is firmly seated. Try power-cycling afterward.

3. Open the PCB Cover:

   • Remove the screws, slide out the main PCB tray, and inspect for power indication LEDs once the machine is turned on.

4. Reflash or Reconfigure (if relevant):

   • If your main PCB is the 34799 model, consider performing a USB reflash of the OS binary and ensuring filenames match the version.

5. Advanced Steps for Older PCBs (31058‑19 or earlier):

   • Disconnect Ethernet before powering on.

   • Disable any Ethernet hubs—connect directly.

   • Possibly update to AMAYA OS v10 if not already running.

   • Uninstall and reinstall software if needed.

6. Verify Motors or Other Faults:

   • If the green light returns after any of these steps, but you're still stuck, the issue might lie with motors or emergency stop circuits.

---

Summary & Next Steps

Issue	Suggested Action
Needle stuck down	Release Z‑bind: use Emergency Stop, lift presser foot, rotate Z shaft, clear presser foot clamping.
“Bad Instruction” error	Indicates CPU/software crash.
Blank screen / no green light	Reseat Ethernet, power cycle, inspect PCB LEDs after opening panel, reflash OS

---

Should You Replace the PCB?

Not necessarily—there are several intermediate steps before PCB replacement. I recommend:

1. Mechanically free the needle using the Z‑bind steps.

2. Power-cycle and reseat Ethernet, checking for LEDs.

3. If no sign of life, consider OS reflash (if main‑PCB model supports it).

4. If none of that works, then replacing the main PCB could be a final step—but only after consulting a trained technician, especially to avoid warranty issues or further

---

Final Thoughts

• Start with mechanical clearance of the needle.

• Then verify connectivity and basic power functionality.

• Try software/firmware fixes next.

• PCB replacement should be a last resort, ideally done by a qualified technician.

Let me know which step you'd like to try first or if you'd like help identifying your PCB model before moving forward.