Dell PowerEdge 2550 - Manual (Page 15)

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Jumpers, Switches, and Connectors
Dell™ PowerEdge™ 2550 Systems Installation and Troubleshooting Guide
Jumpers and Switches—A General Explanation
System Board Jumpers
System Board Connectors
SCSI Backplane Board Connectors
Disabling a Forgotten Password
This section provides specific information about the jumpers on the system board. It also provides some basic information on jumpers and switches and
describes the connectors and sockets on the various boards in the system.
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 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.
Figure A-1. Example Jumpers
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.
Figure A -3 shows the location and default settings of the jumper blocks on the system board. See Table A -1 for the designations, default settings, and
functions of the system's jumpers.
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
Figure A -2 ).
Figure A-2. Example Switches
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 A -3 shows the location of the configuration jumpers on the system board. Table A -1 lists the function of these jumpers.
WARNING: Make sure the system is turned off before you change a jumper setting. Otherwise, damage to the system or unpredictable results
may occur.