Based on the above working principle analysis, the engineer focused on inspecting the regeneration valve core and pilot oil circuit, but did not find any abnormal faults. The cause can be immediately eliminated. When the maintenance technician inspected the one-way valve in the ARM1 valve core, it was found that the throttle hole at the front end of the one-way valve was blocked by foreign objects, which prevented the one-way valve from opening, ultimately leading to the occurrence of this malfunction.

Due to the blockage of foreign objects in the throttle hole, the malfunction occurred without any other abnormal wear and tear. Therefore, it is only necessary to thoroughly clean the throttle hole before retesting. It was found that the pause phenomenon of the recovery arm did not reappear, indicating that the malfunction has been resolved.