Omron CQM1H fatal I/O error

I have an Omron CQM1H PLC that keeps having a reoccurring error. In CX Programmer I read the error as "FATAL I/O". I usually just power it down and unseat and reseat all of the cards and the error will clear. Any suggestions on how I can get this issue to quit or find the specific culprit without replacing the PLC piece by piece?

That fault indicates a problem with one of the connectors between the I/O modules. If the modules are not properly locked together vibration will cause the connectors to work loose.
If all of the module locks are properly in place and you have end barriers installed on the DIN rail then you really don't have any option except replacing the I/O modules one at a time.

Issues with connectors/backplane. The PLC is old and no longer supported. Replace it with a CJ2M - CX-P will convert the program for you. You may have to do a little manipulation of the code but it does it pretty well.

Fatal I/O Error

This is what I was afraid of. I'll try to replace the output cards first. My recommendation to management will be a CJ2 and a complete overhaul of the electrical in the near future.
Scary part of all of this is, we must have dozens of CQM1s, CQM1Hs and C60Ks currently running in our facility.
Job Security!! LOL
Thanks for the input.