Published: 2026-07-09 Article source:
In this video, we will demonstrate how to troubleshoot a black screen issue on a checkweigher touchscreen, using the CW-3K as an example.
A checkweigher is an online weighing device used to inspect product weight and automatically reject non-conforming products. When a fault occurs during operation, troubleshooting should be carried out based on the identified problem.
A black touchscreen on a checkweigher is typically caused by the following three reasons:
If the checkweigher is powered on but the screen remains black, the touchscreen is most likely in Screen Saver mode.
Tap the touchscreen and check whether the display is on or not. If the display recovers, the touchscreen was in Screen Saver mode. It can be disabled if you want the HMI always on.
Note: The screen saver is enabled by default. It is recommended to keep this function enabled to extend the service life of the touchscreen.
First, power off the checkweigher. Long press the touchscreen, while power on the equipment. The touchscreen will enter the calibration interface. Tap "System Parameter Settings" to enter the TPC system settings. Select "Backlight". Then untick the "Auto Backlight" to disable the screen saver function. Close the window and select "Enter Operation Environment". The HMI will return to the checkweigher main interface.
If tapping the screen does not restore the display, while power is supplied to the checkweigher, the electrical cabinet wiring should be inspected.
Before inspecting the main power circuit, disconnect the power supply and verify that all wiring connections are secure and reliable. This helps identify power issues caused by loose or poor connections.
After completing the inspection, power on the equipment.
Use a multimeter to measure the input voltage.
For example, a measured voltage of AC 232.1 V is within the normal range (AC 220 V ±10%), indicating that the external power supply is functioning properly.
(Power Supply Fault: If the voltage exceeds the allowable range (AC 220 V ±10%) or no voltage is detected, the external power supply is abnormal. Check whether power is being supplied correctly.)
If the external power supply works, proceed to check the switching power supply. Measure the input voltage of the switching power supply using a multimeter.
For example, a measured voltage of AC 232.4 V is within the normal range(AC 220 V ±10% ), indicating normal input power.
(Switching Power Supply Fault: If the voltage exceeds the allowable range or no voltage is detected, a fault exists in the main power circuit. Carefully inspect the corresponding wiring and connections.)
You can also observe the switching power supply status indicator is on or not. If the indicator is OFF, the switching power supply itself may be faulty and should be replaced.
If all tests on the main power circuit are normal, proceed to inspect the control circuit.
Since the touchscreen is powered by the control board, first check: Whether the touchscreen cable is securely connected to the control board and measure the voltage at the control board power input.
For example, a measured voltage of DC 23.98 V is within the normal range (DC 24 V ±10%), indicating power supply to the control board.
At this point, inspect the wiring and voltage directly at the touchscreen power input connector. First verify that the touchscreen cable is securely connected. Then measure the power input voltage at the touchscreen.
A measured voltage of DC 23.97 V is within the normal range (DC 24 V ±10%). This indicates that the power cable is functioning properly and the touchscreen itself is defective. It is recommended to replace the touchscreen directly.
If the measured voltage is outside the normal range, the power cable is faulty and should be replaced.
If the voltage measured at the control board power input is abnormal, for example DC 1.614 V, measure the power supply voltage of the control board.
A measured voltage of DC 24.03 V is within the normal range (DC 24 V ±10%). This indicates that the power supply is normal and the control board is defective. The control board should be replaced.
If the measured voltage is outside the normal range, inspect the wiring and power supply between the control board and the DC24V terminal block.
First check whether the control board power cable and DC24V terminal block connections are secure. Then measure the voltage at the terminal block.
For example, a measured voltage of DC 24.06 V is within the normal range (DC 24 V ±10%). This indicates that power at the terminal block is normal, and the fault is likely caused by the power cable or terminal connection. Replace the corresponding cable or terminal.
If the voltage measured at the DC24V terminal block is abnormal:
(Power Supply Fault: Determine whether the issue is caused by: A faulty switching power supply, or a faulty terminal block or wiring connection. )
Then inspect the switching power supply directly. Check that all wiring connections are secure. Measure the output voltage using a multimeter.
A measured voltage of DC 24.06 V is within the normal range. This indicates that the switching power supply is functioning properly and the terminal block is defective. Replacement of the terminal block is recommended.
If the measured voltage is outside the normal range:
(Power Supply Fault: The switching power supply should be replaced. If the terminal block remains abnormal after replacing the switching power supply, the terminal block should also be replaced.)
If multiple same checkweighers are available on-site, cross-testing between machines can help quickly identify the faulty and significantly improve troubleshooting efficiency.
That’s all for today’s video. If you’d like to learn more about checkweigher, feel free to contact General Measure.