Motherboard Assembly (Mba); Continued - Toshiba VP 300 Installation Instructions Manual

5-88 Installation and Maintenance Manual
Installing
Motherboard
Assembly
Toshiba VP Systems Release 7.1 July, 1994
Cables which were disconnected from the MBA in Step 6 are secured to the
bottom panel with cable ties. These cables can remain secured.
11. Disconnect the power harness for the disk drive backplanes (SCSI
Motherboard) at the MBA. Leave the harness ends connected to the disk
drive backplanes.
12. Disconnect the two short flat cables from the MBA. Leave the cables
attached to the top disk drive backplane.
13. Disconnect the fan power harness from the the top disk drive backplane.
14. Remove five screws which secure the MBA to the cabinet from the sides of
the MBA I/O panel.
15. Remove the 18 screws holding the top and bottom of the MBA to the
cabinet and remove the MBA.
16. Remove the power filter harness from the MBA so that it can be installed on
the new MBA.
The hardware used to secure the harness to the MBA (two screws,
two nuts and a lockwasher) are reused when securing the harness to
the new MBA.
To install the Motherboard Assembly, follow the steps below.
It is critical that the MBA be aligned correctly for correct printed
circuit assembly (PCA) engagement. To accomplish this follow the
instructions exactly.
1. Install the power filter harness from the old MBA to the new MBA. See
Figure 5-13 (continued) for proper installation.
2. Remove the OCC chip from the old MBA and place it in the new MBA. See
the Option Control Chip Replacement section in this chapter for the removal
and installation procedures.
3. Hold the new Motherboard Assembly up to the cabinet and install a screw in
the top, center screw-hole to hold it in place. Pass the power harness to the
fan tray through the small rectangular cutout in the bottom of the
motherboard.
4. Install the remaining 17 screws along the top and bottom of the MBA so
that the MBA is just able to move with a minimal amount of distance
between screwheads and MBA. Screws should not be tightened at this time.
5. Install the six screws to the sides of MBA I/O panel but do not tighten the
screws at this time.
6. Push only PCAs in slots A1 and A14 and the Power Supply Assembly into
connectors on the MBA.
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