Dell™ Dimension™ C521 Service Manual Before You Begin About Your Computer Technical Overview Removing the Computer Cover Specifications Troubleshooting System Setup Removing and Installing Parts Replacing the Computer Cover Notes, Notices, and Cautions NOTE: A NOTE indicates important information that helps you make better use of your computer. NOTICE: A NOTICE indicates either potential damage to hardware or loss of data and tells you how to avoid the problem.
Back to Contents Page About Your Computer Dell™ Dimension™ C521 Service Manual Front View Back View of the Computer Back Panel I/O Connectors Front View 1 cover release latch Use this latch to remove the cover. See Removing the Computer Cover. 2 Service Tag Use to identify your computer when you access the Dell Support website or call support. 3 FlexBay drive Can contain an optional floppy drive or optional Media Card Reader.
NOTICE: Ensure that there is a minimum of two inches of space between all vents and any object near these vents. NOTICE: Keep the vent area clean and dust-free to ensure that the system is adequately ventilated. Use only a dry cloth to clean the vent area to avoid water damage to the system. Back View of the Computer 1 voltage selection switch See the safety instructions in the Product Information Guide for more information. 2 power connector Insert the power cable.
NOTE: It is recommended that you use Category 5 wiring and connectors for your network. If you must use Category 3 wiring, force the network speed to 10 Mbps to ensure reliable operation. 3 network activity light Flashes a yellow light when the computer is transmitting or receiving network data. A high volume of network traffic may make this light appear to be in a steady "on" state. 4 surround sound connector Use the (black) surround sound connector to attach multichannelcapable speakers.
Back to Contents Page Before You Begin Dell™ Dimension™ C521 Service Manual Getting Started Recommended Tools Turning Off Your Computer Before Working Inside Your Computer Getting Started This manual provides procedures for removing and replacing the components in your computer. Unless otherwise noted, each procedure assumes that the following conditions exist: l You have performed the steps in Turning Off Your Computer and Before Working Inside Your Computer.
NOTICE: To disconnect a network cable, first unplug the cable from your computer and then unplug it from the network port or device. 2. Disconnect any telephone or network cables from the computer. 3. Disconnect your computer and all attached devices from their electrical outlets, and then press the power button to ground the system board. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before opening the cover. 4.
Back to Contents Page Replacing the Computer Cover Dell™ Dimension™ C521 Service Manual CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide. 1. Ensure that all cables are connected, and fold cables out of the way. Gently pull the power cables toward you so that they do not get caught underneath the drives. 2. Ensure that no tools or extra parts are left inside the computer. 3. To replace the cover: a.
Back to Contents Page Removing the Computer Cover Dell™ Dimension™ C521 Service Manual CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before opening the cover. NOTICE: Before touching anything inside your computer, ground yourself by touching an unpainted metal surface, such as the metal at the back of the computer.
Back to Contents Page Removing and Installing Parts Dell™ Dimension™ C521 Service Manual Memory Battery Cards Processor Drives Power Supply CD/DVD Drive Front I/O Panel Floppy Drive Fan Assembly Media Card Reader System Board Hard Drive Memory If your computer only has one memory module installed on the system board, you can increase your computer memory by installing an additional memory module. Your computer supports DDR2 memory.
NOTICE: If you remove your original memory modules from the computer during a memory upgrade, keep them separate from any new modules that you may have, even if you purchased the new modules from Dell. If possible, do not pair an original memory module with a new memory module. Otherwise, your computer may not start properly. Installing Memory CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.
7. When a message appears stating that memory size has changed, press to continue. 8. Log on to your computer. 9. Right-click the My Computer icon, then click Properties. 10. Click the General tab. 11. To verify that the memory is installed correctly, check the amount of memory (RAM) listed. Removing Memory CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.
Installing an Expansion Card 1. Follow the procedures in Before You Begin. 2. Gently push the release tab on the inside of the card retention door to pivot the door open. Because the door is captive, it will remain in the open position. 3. If you are installing a new card, remove the filler bracket to create a card-slot opening, then continue with step 5. 1 release tab 4. 2 card retention door If you are replacing a card that is already installed in the computer, remove the card.
1 release tab 2 card retention door 4 alignment guide 5 alignment bar 8. 3 filler bracket Close the card retention door by snapping it into place. NOTICE: Do not route card cables over the cards. Cables routed over the cards can prevent the computer cover from closing properly or cause damage to the equipment. 9. Connect any cables that should be attached to the card. See the documentation for the card for information about the card's cable connections.
1 PCI Express x16 card 2 lever 4 securing tab 5 PCI Express x16 card connector 6. 3 securing slot If you are removing the card permanently, install a filler bracket in the empty card-slot opening. NOTE: Installing filler brackets over empty card-slot openings is necessary to maintain FCC certification of the computer. The brackets also keep dust and dirt out of your computer. 7. 8.
1 DVD drive 2 optional floppy drive or media card reader 3 hard drive General Installation Guidelines Connect the SATA hard drive to the connector labeled "SATA0." Connect the SATA CD or DVD drives to the connector labeled "SATA1" on the system board. Connecting Drive Cables When you install a drive, you connect two cables—a DC power cable and a data cable—to the back of the drive and to the system board.
CD/DVD Drive CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before removing the cover. Removing a CD/DVD Drive 1. Follow the procedures in Before You Begin. NOTICE: Do not pull the drive out of the computer by the drive cables. Doing so may cause damage to the cables and the cable connectors. 2.
b. 4. Remove the three shoulder screws from the drive-panel insert. If you are replacing an existing drive: a. Remove the existing drive. b. Remove the three shoulder screws from the existing drive. 5. Insert the three shoulder screws into the sides of the new drive and tighten them. 6. Connect the power and data cables to the drive. 7. Align the shoulder screws with the screw guides, and slide the drive into the bay until it clicks into place. 8.
1 drive release latch 2 floppy drive 4. Disconnect the power and data cables from the back of the floppy drive. 5. Replace the computer cover. See Replacing the Computer Cover. NOTICE: To connect a network cable, first plug the cable into the network port or device, and then plug it into the computer. 6. Connect your computer and devices to electrical outlets, and turn them on.
1 floppy drive 2 slot verification number 8. Slide the drive into the bay until it clicks into place. 9. Connect the data cable to the connector labeled "FLOPPY" on the system board. 10. Replace the CD/DVD drive. 11. Check all cable connections, and fold cables out of the way to provide airflow for the fan and cooling vents. 12. Replace the computer cover. See Replacing the Computer Cover.
1 Media Card Reader 5. 2 drive release latch Replace the computer cover. See Replacing the Computer Cover. NOTICE: To connect a network cable, first plug the cable into the network port or device, and then plug it into the computer. 6. Connect your computer and devices to electrical outlets, and then turn them on. Installing a Media Card Reader CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.
1 Media Card Reader 2 slot verification number 7. Slide the Media Card Reader into the bay until it clicks into place. 8. Connect the power and data cables to the back of the Media Card Reader. 9. Connect the data cable to the USB connector on the system board. 10. Replace the computer cover. See Replacing the Computer Cover. NOTICE: To connect a network cable, first plug the cable into the network port or device, and then plug it into the computer. 11.
1 securing clips (2) 2 hard drive Installing a Hard Drive 1. Check the documentation for the drive to verify that it is configured for your computer. NOTICE: To avoid damage to the drive, do not set it on a hard surface. Instead, set the drive on a surface, such as a foam pad, that will sufficiently cushion it. 2. Unpack the replacement hard drive, and prepare it for installation. 3.
1 hard drive 2 slot verification number NOTICE: To prevent damaging the hard drive, gently slide the drive into the drive bay. Excessive force could damage the hard drive. 7. Gently slide the drive into the bay until it clicks into place. 8. Replace any drives or readers that you removed. 9. Check all connectors to ensure that they are properly cabled and firmly seated. 10. Replace the computer cover. See Replacing the Computer Cover.
To replace the battery: 1. Record all of the settings in system setup (see System Setup Options) so that you can restore the correct settings in step 8. 2. Follow the procedures in Before You Begin. 3. Locate the battery socket. 4. Remove the battery by carefully pressing the battery release lever away from the battery. When the battery release lever is properly pressed, the battery should spring out of the socket. 1 battery 2 battery release lever 3 battery socket 5.
1 heat sink assembly 2 captive screws (2) NOTICE: Unless a new heatsink is required for the new processor, reuse the original heat sink assembly when you replace the processor. 4. 1 Pull the release lever straight up until the processor is released. processor 2 release lever 3 socket NOTICE: Be careful not to bend any of the pins when you remove the processor from the socket. Bending the pins can permanently damage the processor. 5. Remove the processor from the socket.
2. Unpack the new processor, being careful not to bend any of the processor pins. NOTE: You must position the processor correctly in the socket to avoid permanent damage to the processor and the computer when you turn on the computer. 3. If the release lever on the socket is not fully extended, move it to that position. 4. Align the pin-1 corners of the processor and socket.
1 heat sink assembly 10. 2 heat-sink assembly bracket 3 captive screws (2) Replace the computer cover. See Replacing the Computer Cover. NOTICE: To connect a network cable, first plug the cable into the network port or device and then plug it into the computer. 11. Connect your computer and devices to electrical outlets, and turn them on.
1 release button 4 AC power connector 2 power supply 3 screws (2) 5. Slide the power supply toward the front of the computer and lift the power supply up and out of the computer. 6. Lower the replacement power supply into the computer. 7. Slide the replacement power supply toward the back of the computer until it snaps into place. 8. Replace the screws that secure the power supply to the back of the computer chassis. 9. Reconnect the DC power cables. 10. Replace the computer cover.
6. Disconnect the cable attached to the front I/O panel. 7. Remove the screw that secures the front I/O panel to the chassis. 8. Rotate the I/O panel toward the back of the computer and remove and the I/O panel from the computer. 1 securing tab 2 screw 4 I/O panel 5 front panel openings 3 I/O panel bracket Installing the Front I/O Panel 1. Align the I/O panel connectors and lights with the openings in the front panel. 2.
CAUTION: The heat-sink assembly can get very hot during normal operation. Be sure that the assembly has had sufficient time to cool before you touch it. 4. Disconnect the fan power cable from the FAN_CPU1 connector on the system board. See System Board Components. 1 fan tabs (2) 4 fan assembly 2 fan release lever 3 fan cable connector 5.
5. Remove the memory. See Removing Memory. Make a note of where each memory module(s) is installed so that you can reinstall the memory module(s) in the same connector. 6. Remove the processor and heat sink assembly. See Removing the Processor. 7. Remove the fan assemble. See Removing the Fan Assembly. 8. Disconnect all cables from the system board. 9. Remove the eight screws from the system board. 1 system board 10.
Back to Contents Page Specifications Dell™ Dimension™ C521 Service Manual Microprocessor Microprocessor type AMD™ Athlon™ 64 X2 Dual-Core processor AMD Athlon 64 AMD Sempron™ Internal L2 cache up to 1 MB per core up to 256 KB for Sempron Memory Type 533-MHz, 667-MHz, 800-MHz z (when available) DDR2 SDRAM Memory connectors four Memory modules supported 256-MB, 512-MB, or 1-GB non-ECC Minimum memory 256 MB Maximum memory 4 GB Computer Information Chipset nVidia GeForce 6150LE DMA channels e
card size low profile connector size 124 pins connector data width 32 bits (maximum) PCI Express: connectors one x1 and one x16 power 10 W (x1) and 25 W (x16) maximum connector size 36 pins (x1) and 164 pins (x16) connector data width (maximum) one PCI Express lane (x1) and 16 PCI Express lanes (x16) Drives Externally accessible one 3.5-inch drive one 5.
Power DC power supply: Wattage 280 W Heat dissipation 955.39 BTU/hr maximum NOTE: Heat dissipation is calculated based upon the power supply wattage rating. Voltage Backup battery manual selection power supply — 90 to 135 V at 50/60 Hz; 180 to 265 V at 50/60 Hz 3-V CR2032 lithium coin cell Physical Height 11.4 cm (4.5 inches) Width 39.9 cm (15.7 inches) Depth 35.3 cm (13.9 inches) Weight 10.
Back to Contents Page System Setup Dell™ Dimension™ C521 Service Manual Overview Clearing Forgotten Passwords and CMOS Settings Flashing the BIOS Overview Overview Use system setup as follows: l To change the system configuration information after you add, change, or remove any hardware in your computer l To set or change a user-selectable option such as the user password l To read the current amount of memory or set the type of hard drive installed Before you use system setup, it is recommended th
and lists keys and their functions within the active system setup field. System Setup Options NOTE: Depending on your computer and installed devices, the items listed in this section may not appear, or may not appear exactly as listed. System System Info Lists the computer name, BIOS Version, Service Tag, Express Service Code, (if applicable), and the Asset Tag. None of these fields can be modified.
(Auto default) NOTE: A PCI Express graphics card will override the integrated video controller. Video Memory Size This setting configures the amount of system memory that is reserved for the integrated video controller. The settings are Auto, 16MB, 32MB, 64MB, 128MB, or Off. (64MB default) Performance HDD Acoustic Mode (Bypass default) l l l l Bypass — Your computer does not test or change the current acoustics mode setting. Quiet — The hard drive operates at its most quiet setting.
Load Defaults Restores system setup options to their factory defaults. Event Log Allows you to view the Event Log. Entries are marked R for Read and U for Unread. Mark All Entries Read puts an R to the left of all the entries. Clear Log clears the Event Log. POST Behavior Fast Boot When enabled, this feature reduces computer startup time by bypassing some compatibility steps. Off does not skip any steps during computer startup. On starts the system more quickly.
1. Enter system setup, select Boot Sequence from the System group. See System Setup Options. 2. Press to access the menu. NOTE: Write down your current boot sequence in case you want to restore it. 3. Press the up- and down-arrow keys to highlight the appropriate Boot Sequence option. 4. Press the U or D key to move the option up or down in the boot sequence. 5. Press to Save the changes or to Cancel.
Clearing CMOS Settings CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide. 1. Follow the procedures in Before You Begin. 2. Reset the current CMOS settings: 3. a. Locate the 2-pin CMOS jumper (RTCRST) on the system board. See Jumper Locations. b. Remove the jumper plug from pin 1. c. Place the jumper plug on pins 1 and 2 and wait approximately five seconds. d. Replace the jumper plug on pin 1.
Back to Contents Page Technical Overview Dell™ Dimension™ C521 Service Manual Inside View of Your Computer System Board Components Power Supply DC Connector Pin Assignments Inside View of Your Computer CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before opening the cover.
1 fan connector (FAN_CPU1) 2 processor socket (CPU) 3 memory module connectors (DIMM_1, DIMM_2, DIMM_3, DIMM_4) 4 power connector (PW_12V_A1) 5 power connector (POWER1) 6 SATA drive connectors (SATA0, SATA1) 7 front-panel connector (FRONTPANEL) 8 CMOS reset (RTCRST) 9 battery socket (BT1) 10 internal USB (USB1) 11 PCI Express x16 connector (SLOT1) 12 PCI Express x1 connector (SLOT2) 13 PCI connector (SLOT3) 14 password jumper (PSWD) 15 floppy drive connector (FLOPPY1) Jumper Settings
The real-time clock is being reset (jumpered temporarily). jumpered unjumpered - Power Supply DC Connector Pin Assignments DC Power Connector P1 Pin Number Signal name 18-AWG Wire 1 +3.3 VDC Orange 2 +3.3 VDC Orange 3 GND Black 4 VCC (+5 V) Red 5 GND Black 6 VCC (+5 V) Red 7 GND Black 8 PS_PWRGOOD Gray 9 P5AUX Purple 10 V_12P0_DIG White 11 V_12P0_DIG White 12 +3.3 V Orange 13 +3.
23 VCC (+5V) Red 24 GND Black *Use 22-AWG wire instead of 18-AWG wire.
3 +5 VDC Red 4 COM Black 5 +12 VDC Yellow Back to Contents Page
Back to Contents Page Dell™ Dimension™ C521 Service Manual Notes, Notices, and Cautions NOTE: A NOTE indicates important information that helps you make better use of your computer. NOTICE: A NOTICE indicates either potential damage to hardware or loss of data and tells you how to avoid the problem. CAUTION: A CAUTION indicates a potential for property damage, personal injury, or death. Information in this document is subject to change without notice. © 2006 Dell Inc. All rights reserved.
Back to Contents Page Troubleshooting Dell™ Dimension™ C521 Service Manual Dell Diagnostics System Lights Diagnostic Lights Beep Codes Dell Diagnostics CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide. When to Use the Dell Diagnostics If you experience a problem with your computer, perform the checks in this section and run the Dell Diagnostics before you contact Dell for technical assistance.
Configuration Displays your hardware configuration for the selected device. The Dell Diagnostics obtains configuration information for all devices from system setup, memory, and various internal tests, and it displays the information in the device list in the left pane of the screen. The device list may not display the names of all the components installed on your computer or all devices attached to your computer. Parameters Allows you to customize the test by changing the test settings.
A possible USB failure has occurred. No memory modules are detected. Reinstall all USB devices, check cable connections, and then restart the computer. l l l Memory modules are detected, but a memory configuration or compatibility error exists. l l l A possible expansion card failure has occurred. 1. 2. 3. 4. If you have two or more memory modules installed, remove the modules, reinstall one module (see Memory), and then restart the computer.
