7040 Troubleshooting

The WS 7040 driver board has two status indicators: LED1 (Power Indicator) and LED2 (Motor Indicator). The current working status and fault type can be determined by their on/off and flashing patterns.

Power off operation

Before performing any operations involving checking connections, plugging/unplugging harnesses, removing foreign objects, or touching terminals, completely turn off the printer and disconnect the power supply. Do not plug or unplug harnesses or touch terminals while the power is on.

LED1 Status Description (Power Indicator)

LED1 Status	Meaning	Suggested Action
Always on	Normal power supply	Normal working condition
Flashes 2 times in a cycle then pauses	Power supply voltage too low	Check if the supply voltage is 24V, check that the power cord connection is secure
Flashes 3 times in a cycle then pauses	Power supply voltage too high	Check the supply voltage, confirm it does not exceed the 24V upper limit
Off	Driver damaged or power supply/cord fault	First check the power supply and cord; if power is normal but still off, contact after-sales support

LED2 Status Description (Motor Indicator)

Normal Status

LED2 Status	Meaning
Flashing evenly	Motor in standby state
Off	Motor in running state

Slow Flash Fault Codes (Flash in cycle then pause)

LED2 Status	Meaning	Suggested Action
LED1 and LED2 always on simultaneously	Driver board overheat protection	Power off, wait for the driver board to cool down, then retry, and improve heat dissipation
Slow flashes 2 times in a cycle then pauses	Power supply voltage too high or too low	Check if the supply voltage is 24V
Slow flashes 3 times in a cycle then pauses	LM358 current sampling error	Contact after-sales support
Slow flashes 4 times in a cycle then pauses	Fan rotor locked/stalled	Power off and check if the fan blades are blocked by foreign objects
Slow flashes 5 times in a cycle then pauses	Motor phase loss	Power off and check if the motor wire connection is secure
Slow flashes 6 times in a cycle then pauses	Motor Hall sensor issue	Power off and check the motor wire connection, contact after-sales support if necessary

Fast Flash Fault Codes

LED2 Status	Meaning	Suggested Action
Fast flash 1 time	Upper bridge arm abnormality	Contact after-sales support after powering off
Fast flash 2 times	Lower bridge arm abnormality	Contact after-sales support after powering off
Fast flash 3 times	Motor phase wire short circuit	Power off and check if the motor wire is damaged or shorted
Fast flash 4 times	Motor overcurrent protection	Power off and check if the fan blades are jammed, confirm normal load

PWM Signal Test

When the fan does not spin and the LED indicators show no abnormality, use a multimeter to measure the output of the mainboard's PWM signal port to determine if the mainboard is sending the control signal correctly.

Measurement Note

When measuring, avoid shorting adjacent pins with the multimeter probes to prevent damaging the mainboard.

Test Steps:

1. Set the multimeter to DC voltage mode (DC V);
2. Connect the red probe to the PWM signal pin of the mainboard fan port, and the black probe to the GND (low level) of the same fan port;
3. Send different speed commands sequentially via the console, observe if the multimeter reading changes according to the speed steps:

Command	Speed	Expected Reading (5V signal, max_power: 0.9)
Loading...	25%	Approx. 1.1V
Loading...	50%	Approx. 2.3V
Loading...	75%	Approx. 3.4V
Loading...	100%	Approx. 4.5V
Loading...	Off	Approx. 0V

Result Evaluation:

• If the reading increases stepwise with the speed command and drops back to near 0V after M107, the mainboard PWM signal output is normal; the issue lies with the 7040 driver board or the fan itself.
• If the reading remains unchanged, the mainboard is not outputting a signal. Please check if the pin in the [fan] configuration is correct and whether the pin is enabled during firmware compilation.

Tip

The PWM signal is a high-frequency square wave. The multimeter displays the average voltage. The reading is approximately the signal voltage (5V) multiplied by the speed percentage and then by max_power (0.9 in the reference configuration).

Values in the table are for reference only; actual measurements will have tolerances: Due to factors like multimeter accuracy, sampling method, and signal ripple, slight deviations between the reading and the reference value are normal. The key point of judgment is the trend of the reading changing stepwise with the speed command, not a specific exact value.

Suggested Sequence for Troubleshooting

When a fault code appears, it is recommended to troubleshoot in the following order:

1. Record the flashing pattern of LED1 / LED2, compare with the table above to determine the fault type;
2. Power off and check if there are foreign objects in the fan intake, and if the fan blades can be turned manually;
3. Power off and check if the motor wire and power cord connections are secure and free from damage;
4. Confirm the supply voltage is 24V;
5. If all the above checks are normal but the error persists, contact after-sales support.