stuck run time error for an I/O

hello:

I m working on an old version of AB PLC SLC 500/02. when I start it an error code appears xx51. In error message list it is "stuck run time error for an I/O"
I have replaced with new CPU module, but same error appeared.

please help to solve the problem.
hoping to hear from yu soon.

Abdul Haq

hello:

I have solved the prblem. The error code was 0951. I replaced the card with new one at slot #9, The problem vanished.

Abdul Haq