某型挖掘机阀组拆检修复后,动臂举升缓慢且不能回落,通过分析、拆解,发现故障是因动臂换向阀阀杆装配错误所致,重新装配后故障消失。 After a certain type of excavator disassembled and repaired, the boom lift slowly and can not fall back. Through the analysis and disassembly, it was found that the fault was caused by improper assembly of the valve rod of the boom reversing valve and the fault disappeared after reassembly.