E021—Motor stuck

(motor running speed continuous 2s less than 25rpm or the electric current more than 10A)

Step of Solution
1)Appear this error when work in thick materials please enter Ⅱ parameter adjust no. 83(Different thickness materials with different parameters,it depands the actual material
2)First make sure the head mechanical angle is no problem, then check if the contact between power socket and electrical contact is well
3)Judging whether the motor is working or not: using a multimeter (Ω block) to measure motor socket pin 4 and pin1, 2, 3  whether there is short-circuit,or whether the motor three-phase U [3], V [2], W [1] between impedance same issue.
4)check the impedance between the main control board U8 pin 2~7  and pin12 : respectively at around 0.7M, the standby voltage 3.8V
5)check the Impedance  between the main control board U8 pin14, 15, 16  and pin12 : around 10K, the standby voltage : 0V
6)check the Impedance  between the main control board U8 pin1 and pin12(earth) : around  2.4M, the standby voltage:15V
7)Check the Impedance  between the main control board U8 pin10 and pin12(earth): about 1K , The standby voltage: low frequency(when the motor running is high)
8)check  the two terminals impedanceon of main control board D27 : around 2.4M: standby voltage: 15V
9)check the Impedance between the main control board Q3~Q8 pin1 to pin3 : around 10K
10)Check the impedance between encoder on U6  pin3, pin6 and pin2 : around 26K; standby voltage: 5.1V. Whether the U6  pin3, pin6 and the J1 (pin5, pin7 )  connect with the main control socket CN4 (5 feet, 7 feet)
11) If the above detections are normal just change the U8