Micrologix 1200 fault issue

[Brendan B 0]

Hi everyone,

I've have a clients micrologix 1200 with 3 input and 3 output modules coming up with a major error halt fault as well as a retentive data loss fault. With the flashing fault light I am able to connect up to PLC and clear fault for a brief period with the plc able to go into run mode and operate as it would normally. Followed by the fault reoccurring and plc fault light to turn solid red with loss of communications.After resetting It has also shown just major error halt fault with the description with an IO module but unable to determine which module is problematic. I have removed all 24dc power for input IO modules to see if I can narrow anything down. I’m not confident that it is an IO module that is the issue or whether the PLC has finally given up. Hopefully someone may be able to share their opinions on this issue im facing. Thanks 

[pturmel 160]

Before anything else, I would take it apart and inspect/clean all of the bus connections. It only takes a little bit of corrosion to get flaky behavior.