Overview		SCSI Backplane Boards
	Jumpers and Switches—A General Explanation		Interposer Board Connectors
	System Board Jumpers		Disabling a Forgotten Password
	System Board Labels

Jumpers and Switches—A General Explanation

Jumpers and switches provide a convenient and reversible way of reconfiguring the circuitry on a printed circuit board. When installing replacement parts or reconfiguring the system, you may need to change jumper settings on the system board. You may also need to change jumper and/or switch settings on expansion cards or drives.

Jumpers

Jumpers are small blocks on a circuit board with two or more pins emerging from them. Plastic plugs containing a wire fit down over the pins. The wire connects the pins and creates a circuit. To change a jumper setting, pull the plug off its pin(s) and carefully fit it down onto the pin(s) indicated.

NOTICE: Make sure the system is turned off before you change a jumper setting. Otherwise, damage to the system or unpredictable results may occur.

A jumper is referred to as open or unjumpered when the plug is pushed down over only one pin or if there is no plug at all. When the plug is pushed down over two pins, the jumper is referred to as jumpered. The jumper setting is often shown in text as two numbers, such as 1-2. The number 1 is printed on the circuit board so that you can identify each pin number based on the location of pin 1.

Switches

Switches control various circuits or functions in the system. The switches that you are most likely to encounter are dual in-line package (DIP) switches, which are normally packaged in groups of two or more switches in a plastic case. Two common types of DIP switches are slide switches and rocker switches (see the following illustration).

Each of these switches has two positions, or settings (usually on and off). To change the setting of a slide switch, use a small, pointed object such as a small screwdriver or a straightened paper clip to slide the switch to the proper position. To change the setting of a rocker switch, use the screwdriver or paper clip to press down on the appropriate side of the switch. In either case, do not use a pen, pencil, or other object that might leave a residue on the switch.

System Board Jumpers

Figure 1 shows the location of the configuration jumpers on the system board. Table 1 lists the function of these jumpers.

Figure 1. System Board Jumpers

Jumper	Setting		Description
CARDBIOS			Reserved (do not change).
ISA_CLR		(default)	The configuration settings are retained at system boot. The configuration settings are cleared at next system boot. If the ISA configuration settings become corrupted to the point where the system will not boot, install the jumper plug and boot the system. Remove the jumper before restoring the configuration information.
PASSWRD		(default)	The password feature is enabled. The password feature is disabled.
jumpered      unjumpered

System Board Labels

Figure 2. SCSI Backplane Board Connectors

1 Thumbscrew 2 SCSI backplane board 3 SCSI connector (SCSIB) 4 System board interface connector (PLANAR) 5 Power connector (POWER2) 6 SCSI connector (SCSIA) 7 Data cable to optional 5th hard-disk drive SCSI backplane board (Drive5)

Interposer Board Connectors

Figure 3 shows the connectors and sockets located on the interposer board.

Figure 3. Connectors on the Interposer Board

1 Control panel cable connector 2 Cooling fans wiring harness connector (P2) 3 System board interface cable connector (P1) 4 Interposer board power cable connector (P3) 5 Diskette drive/CD-ROM drive interface connector (J1)

Disabling a Forgotten Password

The system's software security features include a supervisor password and a user password, which are discussed in detail in "Using the System Setup Program" of the User's Guide. A password jumper on the system board enables these password features or disables them and clears any password(s) currently in use.

To disable a forgotten supervisor password or user password, perform the following steps.

1. Turn off the system, including any attached peripherals, and disconnect the AC power cable from its power source.
   
   
2. Remove the optional front bezel, if installed.
   
   
3. Open the system doors.
   
   
4. Refer to "System Board Jumpers" for  the location of the password jumper (labeled PASSWRD) on the system board.
   
   
5. Remove the jumper plug from the PASSWRD jumper.
   
   
6. Close the system doors, reconnect the system to an electrical outlet, and turn it on.
   
   The existing passwords are not disabled (erased) until the system boots with the PASSWRD jumper plug removed. However, before you assign a new system and/or user password, you must install the jumper plug.

NOTE: If you assign a new system and/or user password with the jumper plug still removed, the system disables the new password(s) the next time it boots.

7. Repeat steps 1 through 4.
   
   
8. Install the jumper plug on the PASSWRD jumper.
   
   
9. Close the system doors, reconnect the system and peripherals to their electrical outlets, and turn them on.
   
   
10. Assign a new system and/or user password.
    
    To assign a new system password using the System Setup program, see "Using the System Password Feature." To assign a new user password using the System Setup program, see "Using the Setup Password Feature."