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Acer 486 User Manual

Acer 486 motherboards: user guide
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& K D S W H U

System Board

This high-performance, 32-bit personal computer system is based on
the 486 series microprocessor. It features the single-chip upgrade
technology which allows maximum ease and flexibility for upgrading
the system. It is fully compatible with the IBM PC/AT and is suitable
for use as a Windows workstation, CAD/CAE/CAM workstation, UNIX
personal workstation or desktop PC.
The system board accommodates an ISA riser card slot and two 72-
pin SIMM sockets that can hold a maximum memory of 36 MB. The
system architecture is based on the VESA local bus featuring an
onboard VGA. The VGA memory is expandable to 1 MB or 2 MB.
In a LAN environment, the system supports 16-bit Arcnet cards,
Ethernet cards and Token Ring cards. It is fully compatible with Novell
NetWare and Microsoft LAN Manager and also with SCO UNIX,
XENIX and OS/2 operating systems.
The system has a number of software-controlled security features.
These include power-on password, disk drive read/write control,
diskette boot control, serial- and parallel-port control, and a system
setup control.
Installing options such as memory modules, expansion boards and an
upgrade CPU enhance system performance. This chapter gives step-
by-step instructions on how to install these options.
System Board


Table of Contents

Summary of Contents for Acer 486

  • Page 1: System Board

    System Board This high-performance, 32-bit personal computer system is based on the 486 series microprocessor. It features the single-chip upgrade technology which allows maximum ease and flexibility for upgrading the system. It is fully compatible with the IBM PC/AT and is suitable for use as a Windows workstation, CAD/CAE/CAM workstation, UNIX personal workstation or desktop PC.
  • Page 2: System Board Layout

    System Board Layout The system board has the following major components: 486SX, SX2, DX2, or DX4 series CPU 4-MB onboard RAM expandable to 36 MB Two 72-pin SIMM sockets for memory upgrade 128-KB ROM for system BIOS and VGA BIOS 120-pin connector for ISA riser card System clock/calendar Two 9-pin serial ports...
  • Page 3 11. M1431 system chip 12. Second-level cache* 13. Power daughter board connectors 29. VGA upgrade sockets (2 MB) 14. TAG RAM 15. Fan power connector 16. 486 CPU socket Figure 1-1 System Board Layout Optional System Board 17. Power daughter board 18.
  • Page 4: Esd Precautions

    ESD Precautions Electrostatic discharge (ESD) can damage your processor, disk drives, expansion boards, and other components. following precautions before you install a system component. Do not remove a component from its protective packaging until you are ready to install it. Wear a wrist grounding strap and attach it to a metal part of the system unit before handling components.
  • Page 5: Jumper Settings

    Do not attempt the procedures described in the following sections unless you are a qualified service technician. Jumper Settings Figure 1-2 shows the jumper locations. Figure 1-2 Jumper Locations System Board...
  • Page 6 The following tables list the jumper settings and their correponding functions. Table 1-1 System Board Jumpers Jumper Setting JP14 Closed Open JP16 Open Closed JP21 Closed Open JP28 JP37-38 Table 1-2 CPU Clock Selection JP10 JP17 JP19 Function Enable password check Bypass password Enable onboard VGA Disable onboard VGA...
  • Page 7: Cpu Type Selection

    Table 1-3 CPU Type Selection 486 1 486 WB 2 Pentium OverDrive JP11 JP12 JP13 JP18 JP20 JP30-32 Open Open Open JP33 JP34-36 Closed Closed Closed JP39 1-2, 4-5 1-2, 4-5 1-2, 4-5 JP40-41 JP42 JP43 Open Open Open JP46...
  • Page 8: Installing Memory

    Installing Memory The system board has two 72-pin SIMM sockets that accept 1-MB, 2- MB, 4-MB, 8-MB, or 16-MB memory modules with 80 ns (or less) DRAM speed. The maximum system memory size is 36 MB. When installing additional memory, choose one of the SIMM configurations listed in Table 1-5.
  • Page 9: Installing A Simm

    1.5.1 Installing a SIMM Observe ESD precautions when installing SIMMs. See section 1.2. Follow these steps to install a SIMM: Insert the SIMM into the socket at a slight angle, making sure that the cut edge of the SIMM touches the base of the circle mark on the SIMM socket.
  • Page 10: Removing A Simm

    1.5.2 Removing a SIMM Observe ESD precautions when removing SIMMs. See section 1.2. Press the holding clips on both sides of the SIMM outward to release it. Push the SIMM upward. Gently pull the SIMM out of the socket. Figure 1-4 Removing a SIMM 1.5.3 Reconfiguring the System...
  • Page 11: Upgrading The Cpu

    Upgrading the CPU Conventional technology places the CPU on the same board as the ISA bus logic, system memory and I/O interface. The entire system board must be replaced to upgrade the CPU. Single-chip upgrade technology gives you the flexibility to upgrade the CPU by simply inserting a new CPU without replacing the entire system board.
  • Page 12 Insert the upgrade CPU (with the heatsink) into the upgrade socket. Make sure that pin 1 of the CPU corresponds to hole 1 of the upgrade socket (see Figure 1-6). The flat corner on the CPU indicates pin 1. Insert the CPU pins into the socket pinholes gently but firmly.
  • Page 13 Power Daughter Board The power daughter board enables the system to support a 3.3V microprocessor. Without this board, your system can only support a 5V CPU. Follow these steps to install the power daughter board: Before installing, you must check first the voltage requirement of your upgrade CPU.
  • Page 14 Upgrading VGA Memory Observe ESD precautions when installing components. See section 1.2. The VGA memory is upgradable to 1 or 2 MB depending on your onboard VGA chip. The system board may come with either a GD- 5424 or a GD-5429 VGA chip. If your board has a GD-5424, then your VGA memory is expandable to 1 MB only.
  • Page 15 514260 DRAM Figure 1-7 Installing VGA RAM You do not need to change any jumper settings when upgrading the VGA memory. System Board 44256 DRAM 1-15...
  • Page 16: Upgrading Cache Memory

    Upgrading Cache Memory To install cache chips, do the following: Locate the cache sockets on the system board. See Figure 1-1. Align the cut edge of the chip with the cut edge of the cache sockets. See Figure 1-8. U56 U57 U58 U59 U60 U61 U62 U63 Figure 1-8 Installing Cache Gently but firmly insert a 32 Kb x 8, 15 ns SRAM chip into each of...
  • Page 17: Post-Installation Instructions

    The SRAM must have an access speed of 15 nanoseconds. Make sure that you set the jumpers properly. See section 1.4. 1.10 Post-installation Instructions Always observe the following: See to it that the components are installed according to the step- by-step instructions in their respective sections.
  • Page 18: Power Management Feature

    1.11 Power-Management Feature The mainboard incorporates the latest power-conservation technology. However, to take advantage of its energy-saving capabilities, the mainboard must have an Intel SL-Enhanced or a power-saving CPU. The Power-Management feature allows you to monitor system activity. System activity refers to any action involving one or more of the following devices: keyboard, mouse, diskette drives, fixed disk drives, connected peripherals, or video memory.
  • Page 19 Set the independent power-management timers for the VESA DPMS monitor. Valid values are from 1 to 15 minutes. Any video or I/O action returns the system to full power. IDE FIXED DISK STANDBY MODE The IDE Fixed Disk Standby Mode offers a quick-resume power- saving mode for ATA-compliant IDE fixed disks.
  • Page 20 Set the Suspend Mode timer to a value from 2 to 120 minutes, or activate the Suspend/Resume button. LED light on the front panel blinks at a rate slower than when the system is in the Standby mode. button produces two beeps as the system enters the suspend mode. Any keyboard/mouse or I/O action resumes full power.
  • Page 21: Advanced Power Management (Apm)

    1.12 Advanced Power Management (APM) This system features the APM standard designed to further reduce system power consumption. APM is a power-management approach developed jointly by Microsoft and Intel. software applications support APM to take advantage of the power- saving features and offer greater system availability without affecting performance.
  • Page 22 1.14 VESA DPMS The Video Electronics Standard Association (VESA) proposed the Display Power-Management Signaling (DPMS) standard combinations of horizontal and vertical synchronization signals for the PC-VGA monitor. Its purpose is to comply with the U.S. Environmental Protection Agency (EPA) requirements. Table 1-8 lists the different VESA DPMS modes and their functions.
  • Page 23: Software Error Messages

    1.15 Error Messages In the event that you receive an error message, do not continue using the computer. Note the message and take corrective action at once. This section describes the different types of error messages and suggests corrective measures. There are two general types of error messages: Software System...
  • Page 24 Table 1-9 System Error Messages Error Message Bad CMOS Battery Replace battery. Contact your dealer. CMOS Checksum Error Run Setup. Diskette Drive Controller Check and connect the cable to the Error diskette drive or controller. Diskette Drive Error Diskette may be bad. If not, check the diskette drive and replace if necessary.
  • Page 25 Table 1-9 System Error Messages (continued) Error Message Memory Error Check SIMMs on the system board. Contact your dealer. Memory Size Mismatch Run Setup. Serial 1 Conflict Run Setup. Disable onboard serial 1. Serial 2 Conflict Run Setup. Disable onboard serial 2. Parallel Conflict Run Setup.
  • Page 26: Correcting Error Conditions

    1.15.3 Correcting Error Conditions As a general rule, the "Press F1 to continue" error message is caused by a configuration problem which can be easily corrected. equipment malfunction is more likely to cause a fatal error, i.e., an error that causes complete system failure. Here are some corrective measures for error conditions: Run Setup.

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