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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

drives bay (CD/DVD, floppy, media card reader, and hard drive)

2

power supply

3

system board

4

card slots

5

heat sink assembly

6

front I/O panel

System Board Components

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 jumper locations are shown below.

Jumper

Setting

Description

PSWD

Password features are enabled (default setting).

Password features are disabled.

RTCRST

The real-time clock has not been reset.

 

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

+3.3 V

Orange

14

-12 V*

Blue

15

GND

Black

16

PWR_PS_ON

Green

17

GND

Black

18

GND

Black

19

GND

Black

20

NC

N/C

21

VCC (+5V)

Red

22

VCC (+5V)

Red

23

VCC (+5V)

Red

24

GND

Black

*Use 22-AWG wire instead of 18-AWG wire.

DC Power Connector P2

Pin Number

Signal Name

18-AWG Wire

1

COM

Black

2

COM

Black

3

+12 VDC

Yellow

4

+12 VDC

Yellow

DC Power Connector P3

Pin Number

Signal name

18-AWG Wire

1

+12VDC

Yellow

2

COM

Black

3

COM

Black

4

+5 VDC

Red

DC Power Connector P4

Pin Number

Signal Name

22-AWG Wire

1

+5 VCD

Red

2

COM

Black

3

COM

Black

4

+12 VDC

Yellow

DC Power Connector P5 and P6

Pin Number

Signal name

18-AWG Wire

1

+3.3 VDC

Orange

2

COM

Black

3

+5 VDC

Red

4

COM

Black

5

+12 VDC

Yellow

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