The DKJ4100 electric actuator always has the same problem, which is that as soon as the power cord is connected, the output shaft starts to rotate until it reaches full stroke. The feedback current measured with a multimeter varies between 20-4mA when closed and fully open, and the feedback opening indication is also normal. However, the central control cannot control it. No matter how the opening is set, the actuator always runs as soon as the power is turned on. I replaced the central control output terminal (signal input terminal of the actuator) of the faulty machine with the signal input terminal of another normal actuator, which is the same. This eliminates the fault with the central control. Then I replaced the position generator of the actuator and the integrated circuit board for zero and full adjustment, but it still didn't work. I almost didn't replace the motor I don't know how to proceed now, what other possible reasons are there.

What are the troubleshooting methods for DKJ electric actuators?

1. The servo amplifier may be damaged. (This can be difficult to fix on site, so it's better to replace it directly.)
2. The resistance between the two corners of the potentiometer may change and needs to be adjusted accordingly. (This is relatively simple)
3. Use a multimeter to check if the signal output at the central control output terminal (input terminal of the actuator) is normal.
However, it is highly likely that your servo amplifier is damaged and the actuator is in motion, so its motor does not need to be replaced.