Sun Microsystems Ultra 1 140, Руководство по обслуживанию

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System Board and Component Replacement 10-9
10
The jumpers can be set as either RS-423 or RS-232 mode. The jumpers are
preset in RS-423 mode, the default standard for North American users.
RS-232 modes are required for digital telecommunication in nations of the
European Community.
Jumpers are identified on the system board with silkscreened part numbers.
For example, the serial port jumpers are marked J2104 and J2105. Jumper
pins are located immediately adjacent to the part number. Pin 1 is marked
with an asterisk in any of the positions shown. See Figure 10-8.
Figure 10-8 Identifying Jumper Pins
Be sure the serial port jumpers are set correctly. Use a pair of long-nose
pliers to move both jumpers to the correct positions. Table 10-1 shows the
correct setting for the serial port jumpers.
8. Replace the old NVRAM/TOD on the replacement system board.
See Section 10.2.2, “Replacing a NVRAM/TOD,” on page 11.
9. Replace all DSIMMs on the system board.
See Section 10.4, “DSIMM,” on page 18.
10. Replace all SBus card(s) on the system board.
See Section 10.3, “SBus Card,” on page 12.
Table 10-1 Serial Port Jumper Settings
Jumper Pins 1 + 2 Select Pins 2 + 3 Select
Default Shunt
on Pins
J2104 RS-232 RS-423 2 + 3
J2105 RS-232 RS-423 2 + 3
Pins
Part number
J 2 X X X
*
*
*
*
*
*