Exchanging the backplane in the 5094, 5294, 5096, 5296, and 8294 expansion units

Use this procedure in conjunction with Powering off an expansion unit to remove or replace the backplane .

1. Power off the expansion unit using Powering off an expansion unit.
   Note: The primary I/O unit backplane cannot be replaced concurrently.
2. Open the rear cover (see Exchanging the covers in the 5074, 5079, 5094, 5294, 5096, 5296, 8079-002, 8093-002, 8094-002, and 8294 expansion units).
3. Disconnect the plugs to each power supply.
4. From the rear of the expansion unit do the following:
   1. Remove the external cables from the rear of the PCI card enclosure and note their locations.
   2. Remove the EMC access plate that is located directly above the PCI card enclosure. Press the surfaces of the two latching mechanisms together and tilt the top of the cover away from the frame to remove it.
   3. Remove the cables from the top of the PCI cards and note their locations.
      Attention: All cards are sensitive to electrostatic discharge (see Working with electrostatic discharge-sensitive parts).
   4. Remove the screws that hold the PCI card enclosure to the frame.
   5. Pull the PCI card enclosure partially out of the frame while lifting the cables clear of the enclosure.
   6. Press the release mechanism that is located along the top right side of the enclosure and carefully slide the enclosure towards you. Make sure that the cables are clear of the enclosure.
5. Remove the PCI cards from the enclosure and note their locations (see Exchanging cards (dedicated) in the 5074, 5079, 5094, 5294, 5096, 5296, 8079-002, 8093-002, 8094-002, and 8294 expansion units).
6. Install the new PCI card enclosure by reversing the above procedure. Then continue with the next step.
7. Reconnect the power cord(s) and/or the power supply cords that you disconnected earlier.
   Note: The expansion unit will power on automatically.
8. Perform Setting expansion unit configuration ID and MTMS value and then continue with the next step of this procedure.
9. Go to Verifying the repair. This ends the procedure.