How to Troubleshoot Touchscreen Black/White Screen Issues on Your Laser Engraver

Experiencing a black or white screen on your touchscreen panel can be frustrating, but the good news is that most issues can be diagnosed—and often resolved—through a structured step-by-step approach.
This guide walks you through three stages of troubleshooting, from simple checks to deeper hardware diagnostics.

Stage 1: Quick and Basic Checks

1. Verify Power Supply

• Check the power adapter: Ensure the adapter’s indicator light is green.

• Confirm power switches: Make sure both the main power switch and the emergency stop switch are turned ON.

• Observe LEDs: Look at the controller box or mainboard to check if any status or power LEDs are illuminated.

  • If the adapter is green but the machine shows no lights at all, the problem may be in the controller box.

2. Perform a Full Restart

Completely shut down the machine, unplug the power cable, wait 1–2 minutes, then reconnect and restart.
This helps resolve temporary system freezes or UI boot issues.

3. Check Screen Brightness (for dark screens with backlight on)

Some touchscreens have independent brightness controls.
If the screen looks “black” but still emits backlight, try adjusting the brightness through the touchscreen’s internal settings.

4. Consider Auto Sleep Mode

Many touchscreens include auto-sleep/auto-dimming features.
If the screen is blank after idle time but the machine still works, tap the screen or restart to wake it.

5. Listen for Startup Sounds

Check whether the mainboard or controller emits any boot-up beeps or activity noises.

• If yes → The system may be functioning, but the screen or its connection may be faulty.

• If silent, the issue may lie in the mainboard or power distribution.

Stage 2: Internal Cable and Hardware Checks

⚠ Important: Before starting this stage, ensure the machine is fully powered off and the power cable is unplugged. Safety first!

1. Inspect the Touchscreen Cable

Most laser engravers use a ribbon cable or FPC cable.

Steps:

• Open the controller box or the touchscreen housing to locate the cable connecting the touchscreen to the mainboard.

• Reconnect both ends:

  • Gently disconnect the cable from both the screen and the mainboard.

  • Inspect for bent pins or loose connectors.

  • Clean the gold contacts with a rubber eraser or dry cloth.

  • Reinsert firmly and lock the latch.

2. Check for Cable Damage

Look for:

• Creases

• Crushed sections

• Burn marks

• Broken copper traces

Any visible damage means the cable should be replaced.

3. Test Using the Replacement Method (Most Effective)

• Option A: Swap in a known working touchscreen
  If the replacement works, then the original touchscreen is faulty.

• Option B: Connect the problematic touchscreen to a known working machine
  If the issue persists, the touchscreen is confirmed defective.

Stage 3: Identify Core Component Failures

If none of the previous steps resolve the issue, the problem is likely within the core modules.

1. Touchscreen Hardware Failure

A very common cause.

Symptoms:

• Screen permanently black or white

• No boot logo or flickering

• No response despite cable replacement

Causes may include aging, vibration, unstable voltage, or manufacturing defects.

Diagnosis:

• Confirmed via replacement test in Stage 2.

2. Mainboard/Control Board Failure

The display output circuit on the mainboard may be damaged.

How to judge:

• If the machine can still move axes, the laser fires, and the LEDs respond normally:
  → The mainboard is likely fine; the issue is with the touchscreen or cable.

• If the entire machine is unresponsive, with no lights or movement:
  → The mainboard or power distribution system may be faulty.

Final Notes

By following this structured approach—from basic checks to full hardware verification—you can quickly narrow down the root cause of touchscreen display issues. If you identify a defective screen, cable, or mainboard, contact customer support with your findings for a faster resolution.