System Board
The system board is designed with 32-/64-bit auto-detect, auto-switch architecture. It is a high-peformance board that supports both the 486 series and the new Pentium microprocessors, making the 486/Pentium system a performance machine that will last well into the future.
It features single-chip upgrade technology that makes CPU upgrades easy and economical. It is fully compatible with the IBM PC/AT and is suitable for use as a multiuser file server, LAN file server or as a CAD/CAE/CAM workstation.
The system board supports 128-KB system ROM, five 16-bit ISA expansion slots, three PCI local bus slots, a CPU board slot, four 72-pin DRAM sockets, two IDE connectors and one SCSI connector (for SCSI models). Standard features such as two serial ports, one parallel port, a diskette drive interface and an embedded fixed disk drive interface also reside on the system board.
The system board supports a maximum memory of 128 MB using 4- and 16-MB single-density, 8- and 32-MB (with parity) double-density, and 2-MB (without parity) SIMMs.
System Board |
1-1 |
The system board has the following major components:
∙Four 72-pin SIMM sockets arranged in two banks (labeled Bank 0 and Bank 1)
∙DRAM controller with page/faster page mode and burst read capability
∙One CPU board slot
∙Four 16-bit ISA expansion slots supporting master add-on cards
∙Two PCI slots
∙One full-function ISA/PCI slot
∙Real-time clock with 5-7-year battery
∙128-KB flash ROM used as system BIOS
∙PS/2 keyboard and mouse interface
∙Reset and front-panel LED interface for ID3P or IDAB housing
∙Onboard National PC87332 chip that supports one parallel port, two serial ports, one IDE port, and one FDD port
∙Onboard AIC-7850 chip that supports one 8-bit SCSI-II port (one port supports seven devices)
∙Enhanced IDE (PCI to IDE) on PCI bus that supports two IDE ports for four IDE devices
Figure 1-1 shows the system board layout and the locations of the major components.
1-2 |
User’s Guide |
221 12 |
23 34 |
45 |
56 |
67 |
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21 |
BANK 1 |
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22 |
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210 |
BANK 0 |
87 |
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20 |
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19 |
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8 |
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9 |
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9 |
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10 |
198 |
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110 |
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18 |
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11 |
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12 |
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17 |
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132 |
17 |
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16 |
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16 |
14 |
15 |
14 |
15 |
13 |
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1 |
COM2 |
12 |
HDD LED connector 1 |
2 |
Printer port |
13 |
Reset/SMI connector 1 |
3 |
IDE connector |
14 |
Real-time clock |
4 |
FDD connector |
15 |
System BIOS (flash ROM) |
5 |
Power connector |
16 |
ISA slots |
6 |
CPU board slot |
17 |
Keyboard controller |
7 |
SIMM sockets |
18 |
ISA/PCI slot 2 |
8 |
SCSI connector |
19 |
PCI slots |
9 |
Enhanced IDE1 connector |
20 |
PS/2 mouse connector |
10 |
Enhanced IDE2 connector |
21 |
COM1 |
11 |
Power LED connector 1 |
22 |
PS/2 keyboard connector |
Figure 1-1 System Board Layout
1The connector version varies depending on the system housing. The system may come with either an IDAB or an ID3P housing.
2You cannot use both slots at the same time.
System Board |
1-3 |
Electrostatic discharge (ESD) can damage your processor, disk drives, expansion boards, and other components. Always observe the following precautions before you install a system component.
1.Do not remove a component from its protective packaging until you are ready to install it.
2.Wear a wrist grounding strap and attach it to a metal part of the system unit before handling components. If a wrist strap is not available, maintain contact with the system unit throughout any procedure requiring ESD protection.
1.3Pre-installation Instructions
Always observe the following before you install a system component:
1.Turn off the system power and all the peripherals connected to the unit before opening it.
2.Open the system according to the instructions in the housing installation manual.
3.Follow the ESD precautions in section 1.2 before handling a system component.
4.Remove any expansion boards or peripherals that block access to the SIMM sockets or CPU socket.
5.See the following sections for specific instructions on the component you wish to install.
Do not attempt the procedures described in the following sections unless you are a qualified service technician.
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User’s Guide |
The system has a separate board for the CPU and the second-level cache. The single-chip upgrade technology gives you the flexibility to upgrade the CPU by simply inserting a higher 486 CPU or a Pentium CPU. Refer to Chapter 2 for detailed instructions on how to upgrade the CPU.
You have to change the jumper settings on the system board whenever you reconfigure the system.
Follow these steps to change a jumper setting:
1.Shut off the system power.
2.Remove the jumper cap from the jumper.
3.Position the jumper cap over the two pins for the desired function.
4.Gently press the cap into place.
Figure 1-2 shows the jumper locations.
System Board |
1-5 |
Figure 1-2 System Board Jumper Locations
Table 1-1 lists the system board jumpers settings and their corresponding functions.
Table 1-1 |
System Board Jumper Settings |
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Jumper |
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Setting |
Function |
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JP1 |
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2-3* |
Disregards password |
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1-2 |
Enables password |
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JP2 |
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1-2* |
Enables reset function |
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Open |
Disables reset function |
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JP3 |
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1-2* |
BIOS |
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2-3 |
Reserved |
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JP4 |
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1-2* |
128 bytes or 256 bytes (NVRAM) |
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2-3 |
4 Kbytes, reserved (NVRAM) |
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JP6 |
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1-2* |
Enables onboard buzzer |
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2-3 |
Enables external speaker |
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*Default setting
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User’s Guide |