Genie-S125-Hydraulic System-No response when the emergency action big arm drops

1. Case developer

Case developer: Zhou Weijin
A business store: Xiamen Maintenance Group
Case fixed manuscript time: April 13, 2022
 

2. Vehicle information registration

1. Manufacturer: Genie
2. Model: S125
3. Serial number: S12516D-1465
4. Number of working hours: 5374 H
5. Failure code: None
6. Failure system: hydraulic system
7. Failure phenomenon: Big arms have no response when emergency decline.

 

3. fault phenomenon confirmation

In the process of repairing and testing each function, the device found that the device was testing all the functional actions when the engine was started; and only when the operation of the operation was discovered, the emergency pump was operated when the operation was reduced. There is a failure of the lower arm.

4. analysis of the cause

1. Determine as an electrical failure: the module output external control line and the aging of the electromagnetic valve coil, etc.
2. It is judged as a hydraulic failure: the overflow valve aging, the electromagnetic valve core card plug and the internal wear of the valve core, etc.

5. Check and repair steps

1. Check the "LCD display"
     Checking process: Check the status of the device through the display. At this time, the display screen is normal and there is no fault prompt.
     Judgment results: The device may be a short -term failure or hydraulic system failure, and the system module does not make effective failure records.

2. The analysis may be insufficient battery storage voltage, resulting in abnormal power supply of modules
     Inspection process: The measurement voltage of the DC mode through the tool "universal table" is "12.5V", and
     Judgment results: Emergency battery storage output voltage values ​​are normal, and confirm that the battery power supply is normal.

3. Check the external control line of the solenoid valve: (use tool: universal table)
     Checking process: Directly measure the load circuit terminal. By checking the electrical schematic diagram, the "universal table" tool DC mode is used to measure the "C02PBD-RD/BK" and "Valve RTN7" coil power supply when operating the device.


     The judgment results: The "universal table" was measured as DC11.7V, and the output of the system board card output to the coil load end was normal.



4. Check the related valve group of the hydraulic circuit: (using tools: hydraulic gauge, blocked)

     Checking process:

 a) The "TP" measurement of the "TP" measurement of the function valve set was measured by the "hydraulic gauge" tool, only about 80BAR (1160 PSI), and the pressure loss was serious.





b) Use the "hydraulic gauge" tool to measure the "TP" measurement of the "TP" of the four -wheel steering valve set when operating the device. There are about 50BAR (725 PSI).





 c) By blocking the oil outlet of the "AA direction valve-P2 out", the test is found when the arms are used to do emergency decline when the operation is operated. The pressure is restored to normal.



     Judgment results: Through stress testing and actual actions, the failure has been confirmed that the "AA direction valve" spare parts must be repaired.

5. Final failure point and solution: Through the above analysis and investigation, the failure phenomenon is judged as the "AA direction valve" valve core's internal wear string oil. Confirm that the fault has been excluded.

 

6. Summary of experience and refinement

1. Summary of experience: Repair equipment is preferred to judge the direction of electrical directions (required commonly used tools such as universal tables, electric pens, etc.). It is prompted to further confirm whether the electrical component is normal for power supply; after the above investigation, the failure is not eliminated before the mechanical direction is tested (a common tool hydraulic table, a dedicated spanner, a block, etc.), the hydraulic failure must be the function of the hydraulic principle drawings and various hydraulic components. There is a certain understanding. For multi -functional integration valve groups, the position and number of the component on the maintenance manual must be carefully checked in order to achieve the correct measurement and judgment.

2. Skills harvest: The output flow of the oil pump in the hydraulic circuit under the engine state is large, and the failure appears obvious during operation. In the emergency state The pressure in the middle cannot be established. Due to the concealment, diversity, and causes of hydraulic system faults, failure to judge not only need to combine theoretical knowledge and sufficient maintenance experience during maintenance, but also equipped with professional pressure measurement tools. Endemication and improvement of work efficiency.