请教CA1500负压的监测原理及分析故障解决思路

如题，谢谢

Vacuum Error (55)
(1) Purpose
To monitor abnormal vacuum
(2) Detection Method
The output voltage of the “400 mmHg” vacuum sensor is monitored through A/D convertor.
Error is checked if the sensor output voltage exceeds the specified range (360 mmHg or
less) for at least 12 seconds.
(3) CA-1500’s Action
Stops the reagent dispensing. Discard the reaction tubes in the heater unit and the detector
well (after analysis).
(4) Cause
1) Leakage from the vacuum path
2) Malfunction of the pneumatic unit
3) Defective PCB No. 2136
4) Defective PCB No. 4079 (Pneumatic unit is not turned ON)
(5) Corrective Action
1) Check the pressure path.
2) Check the pneumatic unit.
3) Check the PCB function.

关于负压问题在维修手册上的详细信息郑老师已经专门回复，我只补充我的经验：如果是没有负压调节装置的老机器一旦报负压问题需要更换负压组件的几率很大，如果是有负压调节装置的新机器在清理负压组件后进行调压少数能够解决问题。多数机器一年内不会报负压问题（高原除外），更换负压组件后一个月左右需要打开清理污垢一次，否则很快会报警。