Fans - DEC 4000 Model 200 Operation Manual

bus with more than one expander, the power control bus
signal is passed along, using the secondary in and out
connectors as shown in Figure 1–11.
The secondary out (SO) connector sends the signal down
the power bus for configurations of more than one
expander.
Figure 1–11: Sample BA430 Power Bus Configuration
System

1.1.1.6 Fans

Two fans located under the card cage draw air in through the top of the
enclosure, down through the card cage, and out the bottom. The speed of
the fans varies, depending on the surrounding room temperature. To reduce
the load on the fans, keep the system away from heat sources. Figure 1–12
shows the air flow through the system enclosure.
NOTE: The power supply monitors the fans. If either fan stops working,
the Fan Failure indicator on the power supply lights, and the system
automatically shuts down as a precautionary measure. Call your Digital
service representative if a fan fails.
1–18 VAX 4000 Model 200 (BA430) Operation
Expander 1 Expander 2
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