Technical data

and internal cabling found in other enclosures. This design is easier to
maintain since it eliminates problems caused by faulty internal cabling.
• Modules that do not have external I/O connections have blank bulkhead
covers.
The module handles and blank covers form an electrical noise seal that
complies with requirements for electromagnetic interference (EMI) by
(1) keeping radio frequency interference generated by the system in the
enclosure and (2) keeping external radio frequencies from entering the
enclosure. The module handles and blankcovers also help guarantee proper
airflow.
Each handle or cover has two captive quarter-turn Phillips screws to hold
the module in the card cage. Module handles also use levers to help install
or remove a module from the card cage.
The five basic types of handles and covers or panels used for BA400-series
compatible modules are:
• Single-width flush handle
• Single-width recessed handle
• Single-width ratchet ejector handle (BA440 CPU and memory only)
• Single-width blank cover
• Double-width console panel (BA430 only)
1.3.1 Filler Panel Between Flush and Recessed Handles
When you use a flush-handle module next to a recessed-handle module, you
must install a metal filler panel (Figure 1–3) between the modules. Without
the filler panel, circuitry on a flush-handle module adjacent to the recessed-
handle module is exposed. The filler panel (70–24505–01) has four sets of
finger stock that provide an effective chassis ground between the handles.
Flush handles and covers have screw holes at the top and bottom of each
side for the installation of this filler panel.
Ratchet ejector handles are only used with some CPU and memory modules
(Figure 1–3). To install a module with ratchet ejector handles, insert the
module into the guide slot and position the ratchet ejector fingers into the
latching slots at the top and bottom. Press the ratchet levers in until
the module is seated in the backplane. Latch the ratchet ejectors when
a positive feel of the bottom is realized. This removes any slack that may
exist between the module fingers and the backplane. These handles are
used to ensure a positive connection of the module in the backplane.
1–4 BA430/BA440 Enclosure Maintenance