4-24 Dell WorkStation 400 Systems Service ManualS ystem BoardFigure 4-25. System Board RemovalTo remove the system board, follow these steps:1. Rotate the power supply out of the way (see Figure 4-14).2. Disconnect all cables from their connectors at the back of thecomputer.3. Remove the expansion-card cage.4. Remove the microprocessor fan.5. Disconnect all cables from the system board.6. Remove the hard-disk drive power cable(s). Slide any drives in the5.25-inch bays toward the front of the computer, but leave them cabled.7. Remove the screw that secures the system board to the bottom of thecomputer.8. Slide the system board toward the front of the chassis until it stops.9. Carefully lift the system board out of the chassis (be sure to lift evenlyand not twist the system board).If you are replacing a system board, remove the DIMMs, the primary processorSEC cartridge/heat sink assembly, and the terminator card or secondary proces-sor assembly, and install them on the replacement board.When you reinstall the system board, before you slide the system board back tolock it into position, push down near each slot to engage the grounding clip ontoits corresponding tab. Push evenly on both sides of the system board as youslide it into position (do not twist the system board).screwslots (7)tabs (7)
