Specifications

9-12 • Quick Reference AlphaServer 1000A Owner's Guide
System Board and CPU Card Jumper Settings
Table 9-7 lists the default jumper settings for the system board. The jumper settings
are shown in Figure 9-6.
Table 9-7 System Board Default Jumper Settings
Number Name Description and Default
J16 Large fan Allows the large fan to be disabled.
Enabled.
J27 VGA enable Enables the on-board VGA logic.
Enabled. Set to the disabled position
(pins 2 and 3) when using a graphics
option card.
J50 FROM VPP enable Permits the 12 volts needed to update
the Flash ROMs. Enabled.
J51 SCSI terminator Enables the on-board SCSI
terminators. The system specification
requires that the SCSI bus be
terminated at both ends. Enabled.
J52 Temperature
shutdown
Allows the temperature chips to shut
down the system in an orderly
sequence. Enabled.
J53 Fan shutdown Allows the software to shut down the
system in the event of a fan failure.
Enabled.
J55 Small fan Allows the small fan to be disabled.
Enabled.
J56 Fan fault Allows hardware to detect a fan fault
and shut down the system in an
orderly sequence. Enabled.
Set to disable if testing the system
board or CPU card outside of the
enclosure.