Hello all, I have a Controllogix 1756-L61 with some RIO. There are a couple of 1734-OB4E's that have gone bad. (no output voltage) My boss found some online and we received them the other day. 7 of them. Same part number, same series, revision 3.022. The configuration for keying is setup as "compatible module" with the major revision at 3 and the minor at 1. My understanding is if the replacement is the same, or higher, with the minor revision we should have no problem. Correct? Because all 7 of these modules we received do not work. I suppose it's possible, but I find it difficult to believe they're all bad.