BL20 PG4 will not power up in new enclosure

[Penkare]

In an effort to retire the BL20 PG3 blade servers we are moving all our G4s to one rack. Two slots remain yet moving the G4's to these results in them being unable to power up. The yellow light is on and I can connect to the ILO but we can not turn the server on. There is no problem with the servers because if we move them back to their old rack they will power up fine. This is a problem with slots one in enclosures 4 and 5 of our rack. I am wondering if anyone has seen this issue before.