Acer V12LC User manual

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System Board
System Board 1-1
The V12LC is a high-performance Pentium PCI-based system board
that supports the 64-bit Pentium microprocessor running at
75/90/100/120/133/150 MHz and has a 16-KB internal write-back
cache. It utilizes the Peripheral Component Interconnect (PCI) local
bus architecture. The PCI local bus maximizes the system
performance by enabling high-speed peripherals to match the speed
of the microprocessor with its 120 MB or 132 MB per second transfer
rate in burst mode.
The system board features a slot for the PCI/ISA slot board and two
PCI enhanced IDE interfaces with a zero-wait state 11 MB per second
transfer rate and support up to four IDE devices. It has buffered serial
ports that reduce the number of interrupts to avoid slowing other
system activities. With the optional ECP/EPP function, the parallel
port transfers data at a fast 2 MB to 10 MB.
The system board has two DRAM banks composed of four 72-pin
sockets that support both single- and double-density SIMMs for a
maximum memory of 128 MB.

1-2 User’s Guide
1.1 Major Features
The system board has the following major features:
•Pentium 75/90/100/120/133/150 MHz CPU in a zero-insertion
force (ZIF) socket
•Two DRAM banks composed of four 72-pin SIMM sockets that
support 4/8/16/32-MB 60/70ns SIMMs
•16-KB internal cache and 256-KB write-back second-level cache
•128-KB Flash ROM for system and VGA BIOS
•Two PCI enhanced IDE interfaces that support up to four IDE
devices
•System clock/calendar with 128 bytes CMOS RAM
•Cirrus 5430/5434/5440 VGA PCI accelerator that supports up to
2-MB video memory for a resolution up to 1280x1024 with 256
colors non-interlaced or 1024x768 with 65,536 colors interlaced
•External ports:
•PS/2 keyboard/mouse ports
•Two buffered high-speed serial ports
•One ECP/EPP high-speed parallel port
•Video port
•Feature socket for multimedia or Ethernet solution (optional)
•RJ-45 phone jack (optional)

System Board 1-3
1.1.1 Layout
Figure 1-1 shows the locations of the system board major
components.
1 Keyboard controller
2 Feature socket for multimedia
or Ethernet solution (optional)
3 Flash memory BIOS
4 Real-time clock
5 Slot board connector
6 Voltage regulator
7 Second-level cache
8 SIMM sockets
9 320-pin ZIF CPU socket
10 Video memory chips
11 Video memory upgrade sockets
12 Video port
13 Parallel port
14 COM2
15 COM1
16 PS/2 Mouse connector
17 PS/2 keyboard connector
18 RJ-45 phone jack (optional)
Figure 1-1 System Board Layout

1-4 User’s Guide
1.1.2 Slot Board
The system board comes with a slot board already installed. The slot
board carries the PCI and ISA bus slots for system enhancements and
future expansion.
The slot board may vary in size and layout depending on your system
housing. Figures 1-2 to 1-5 show the four kinds of slot boards.
Figure 1-2 2-PCI/3-ISA Slot Board (for generic desktop systems)
Figure 1-3 2-PCI/3-ISA Slot Board (for Aspire desktop systems)

System Board 1-5
Figure 1-4 3-PCI/5-ISA Slot Board
(for generic mini-tower systems)
Figure 1-5 3-PCI/4-ISA Slot Board
(for Aspire mini-tower systems)

1-6 User’s Guide
1.2 Jumpers and Connectors
1.2.1 Jumper and Connector Locations
Figure 1-6 shows the jumper and connector locations on the system
board.
Figure 1-6 System Board Jumper and Connector Locations
Jumpers are prefixed “JP”. Connectors are
prefixed “CN”.
The blackened pin of a jumper represents
pin 1.

System Board 1-7
1.2.2 Jumper Settings
Table 1-1 lists the system board jumpers with their corresponding
settings and functions.
Table 1-1 System Board Jumper Settings
Jumper Setting Function
BIOS Type
JP1 1-21
2-3 For models with Acer BIOS For models with OEM BIOS
Password Check
JP2 1-2
2-31Check password
Bypass password
BIOS ROM Type
JP3 Open
1-2
2-31
For 29EE010 only
EPROM
Flash ROM (Intel 28F010, 28F001,
or 28F101)
Onboard SMC665/669
JP6 1-2
2-31Disabled Enabled
CPU Local Bus Clock
JP8 1-4
2-51
3-6
50 MHz (Pentium 75 MHz)
60 MHz (Pentium 90/120/150 MHz)
66 MHz (Pentium 100/133 MHz)
CPU Type
JP12 1-21
2-3 Intel P54C or AMD K5 Cyrix M1
When your Flash ROM is Intel 28F001 (JP3
is set to pins 2-3), refer to JP20 for the Flash
ROM control settings.
1Default setting

1-8 User’s Guide
Table 1-1 System Board Jumper Settings (continued)
Jumper Setting Function
CPU Voltage
JP13 1-21
2-3 3.3825V for VR and standard CPU type
3.5250V for VRE CPU type
CPU Core / Local Bus
Clock Ratio
JP14, JP18 1-21, 1-21
2-3, 1-2
1-2, 2-3
2-3, 2-3
Intel P54C M1 and K5
3/2 3/2, 2/2, 3/1
2/1 1/1
3/1 3/2, 2/2, 3/1
5/2 1/1
Reset Switch
JP15 1-2
2-31For suspend mode function
For reset function
CN1 Connector Type
JP16, JP17 1-21
2-3 Feature Connector I2C interface
HDD/FDD LED Control
JP19 Open1
Closed
Detects HDD accesses only
(for generic housings)
Detects HDD and FDD accesses
(for Aspire housings only)
Flash ROM Control
JP20 1-2
2-31
(For Intel 28F001 only)
Programming boot block
Normal work or programming blocks
other than boot blocks
The settings of JP8, JP13, JP14, and JP18
depend on the Pentium CPU type.
1Default setting

System Board 1-9
1.2.3 Connector Functions
Table 1-2 lists the different connectors on the system board and their
respective functions.
Table 1-2 Connector Functions
Connector Function
CN1 VGA feature connector
CN2 PCI IDE channel 1
CN3 PCI IDE channel 2
CN4 Diskette drive connector
CN5 Power connector
CN6 Multifunction connector
CN7 Multifunction connector
CN8 Hard disk LED connector
CN9 Reserved
CN10 Feature socket for multimedia or
Ethernet card
Figures 1-7 and 1-8 show the pin assignments of multifunction
connectors CN6 and CN7 respectively.
Figure 1-7 20-Pin Multifunction Connector (CN6)

1-10 User’s Guide
Figure 1-8 8-pin Multifunction Connector (CN7)
1.3 ESD Precautions
Always observe the following electrostatic discharge (ESD)
precautions before installing a system component:
1. Do not remove a component from its antistatic packaging until
you are ready to install it.
2. Wear a wrist grounding strap before handling electronic
components. Wrist grounding straps are available at most
electronic component stores.
Do not attempt the procedures described in
the following sections unless you are a
qualified technician.

System Board 1-11
1.4 Memory Upgrade
The system board comes with four 72-pin SIMM sockets that support
4-MB and 16-MB single-density SIMMs and 8-MB and 32-MB double-
density SIMMs. Table 1-3 lists the possible memory configurations.
Table 1-3 Memory Configurations
Bank 0 Bank 1 Total
SIMM-1 SIMM-2 SIMM-3 SIMM-4 Memory
4 MB 4 MB 8 MB
4 MB 4 MB 8 MB
8 MB 8 MB 16 MB
8 MB 8 MB 16 MB
4 MB 4 MB 4 MB 4 MB 16 MB
4 MB 4 MB 8 MB 8 MB 24 MB
8 MB 8 MB 4 MB 4 MB 24 MB
8 MB 8 MB 8 MB 8 MB 32 MB
16 MB 16 MB 32 MB
16 MB 16 MB 32 MB
4 MB 4 MB 16 MB 16 MB 40 MB
16 MB 16 MB 4 MB 4 MB 40 MB
8 MB 8 MB 16 MB 16 MB 48 MB
16 MB 16 MB 8 MB 8 MB 48 MB
16 MB 16 MB 16 MB 16 MB 64 MB
32 MB 32 MB 64 MB
32 MB 32 MB 64 MB
4 MB 4 MB 32 MB 32 MB 72 MB
32 MB 32 MB 4 MB 4 MB 72 MB
8 MB 8 MB 32 MB 32 MB 80 MB
32 MB 32 MB 8 MB 8 MB 80 MB
16 MB 16 MB 32 MB 32 MB 96 MB
32 MB 32 MB 16 MB 16 MB 96 MB
32 MB 32 MB 32 MB 32 MB 128 MB

1-12 User’s Guide
1.4.1 Installing a SIMM
Follow these steps to install a SIMM:
1. Slip a SIMM at a 45°angle with the component side facing down
into the socket labeled SIMM-1.
Be careful when inserting SIMMs to avoid
damaging the SIMM or the socket.
2. Gently press the SIMM up until the pegs of the socket fit into the
holes on the SIMM and the holding clips lock the SIMM into
position. The SIMM should be at a 90°angle when installed.
Figure 1-9 Installing a SIMM

System Board 1-13
1.4.2 Removing a SIMM
Follow these steps to remove a SIMM:
1. Press the holding clips on both sides of the SIMM outward to
release it.
Figure 1-10 Removing a SIMM
2. Move the SIMM to a 45°angle.
3. Pull the SIMM out of the socket.
Always remove SIMMs from the socket
labeled SIMM-4, then SIMM-3, and so on.

1-14 User’s Guide
1.4.3 Reconfiguring the System
You must enter Setup after installing or removing SIMMs to
reconfigure the system.
Follow these steps to reconfigure the system:
1. Turn the system on. A memory error message appears,
indicating that the total memory does not match the value stored
in CMOS.
2. Press E
+D +A to enter Setup. A warning message
appears indicating a wrong memory configuration.
3. Press A
twice to exit and reboot the system.
The system boots with the new memory configuration.
1.5 IDE Fixed Disk Support
The system board supports four IDE fixed disks, or any other IDE
devices, through the two onboard PCI IDE interfaces. See Figure 1-1
for the location.
Follow the instructions in the housing installation manual on how to
install a fixed disk in the system. Connect the cables according to the
IDE fixed disk configuration in Table 1-4
Table 1-4 IDE Fixed Disk Configuration
IDE Connector Master Slave
Channel 1 Fixed Disk 0 Fixed Disk 1
Channel 2 Fixed Disk 2 Fixed Disk 3

System Board 1-15
1.6 CPU Installation
The system board comes with a zero-insertion force (ZIF) CPU socket
for easy installation.
Follow these steps to install a Pentium CPU:
1. Lift up the socket lever.
2. Insert the CPU to the socket. Make sure that the notched corner
of the CPU matches the pin 1 indicator on the socket.
Be careful not to bend any pins.
3. Pull down the socket lever.
Figure 1-11 Installing a Pentium CPU
4. Set jumpers JP8, JP14, and JP18 according to the CPU speed,
JP12 for the correct CPU type, and JP13 for the appropriate CPU
voltage. Refer to Table 1-1 for the jumper settings.

1-16 User’s Guide
1.7 Video Memory Upgrade
Larger video memory allows you to display higher resolutions and
more colors. The system board comes with a 1-MB video memory
onboard upgradable to 2 MB.
Follow these steps to upgrade the video memory:
1. Locate the video DRAM upgrade sockets labeled U12 and U13
on the system board. See Figure 1-1.
2. Gently insert a 514260ASL (256K x 16, 70ns SOJ) chip into each
of the upgrade sockets.
Make sure that the pin 1 indicator on the chip
matches the notched corner of the socket.
Figure 1-12 Installing a Video Memory Chip
Pin 1 Indicator
Notched Corner

System Board 1-17
1.8 Error Messages
Do not continue using the computer if you receive an error message of
any type. Note the message and take corrective action. This section
explains the different types of error messages and corresponding
corrective measures.
There are two general types of error messages:
•Software
•System
1.8.1 Software Error Messages
Software error messages are returned by your operating system or
application. These messages typically occur after you boot the
operating system or when you run your applications. If you receive
this type of message, consult your application or operating system
manual for help.
1.8.2 System Error Messages
A system error message indicates a problem with the computer itself.
A message of this type normally appears during the power-on self-test,
before the operating system prompt appears.
Table 1-5 lists the system error messages.

1-18 User’s Guide
Table 1-5 System Error Messages
Message Action
CMOS Battery Error Replace the RTC chip or
contact your dealer.
CMOS Checksum Error Check the RTC chip and the
necessary jumper. If the
battery is still good, run
Setup.
Display Card Mismatch Run Setup
Diskette Drive Controller
Error or Not Installed Check and connect the control cable to the diskette
controller.
Diskette Drive Error Diskette may be defective. If
not, replace the diskette drive.
Diskette Drive A Type
Mismatch Run Setup and select the proper drive type.
Diskette Drive B Type
Mismatch Run Setup and select the proper drive type.
Equipment Configuration
Error Modify the memory configuration to agree with
one of the options in Table
1-3.
Fixed Disk Controller Error Run Setup.
Fixed Disk 0 Error Check all cable connections.
Replace fixed disk.
Fixed Disk 1 Error Check all cable connections.
Replace fixed disk.
Keyboard Error or No
Keyboard Connected Check and connect the keyboard to the system unit.
Keyboard Interface Error Replace the keyboard or
contact your dealer.

System Board 1-19
Table 1-5 System Error Messages (continued)
Message Action
Memory Error at:
MMMM:SSSS:OOO
(W:XXXX, R:YYYY)
where:
M: MB, S: Segment,
O: Offset, X/Y: write/read
pattern
Check SIMMs on the system
board. Contact your dealer.
Memory Size Mismatch
CPU Clock Mismatch Run Setup. Check if the values
shown in the memory
parameters are correct. If
correct, exit Setup and reboot
the system. If the error
message reappears, ask for
technical assistance.
Onboard Serial Port 1
Conflict Run Setup and disable the port.
Onboard Serial Port 2
Conflict Run Setup and disable the port.
Onboard Parallel Port Conflict Run Setup and disable the
port.
Pointing Device Error Check and connect pointing
device.
Pointing Device Interface
Error Replace the pointing device or contact your dealer.
Press Okey to continue or
E
+D +A for Setup Press Oor
E
+D +A to enter
Setup.
Real Time Clock Error Check the RTC chip. If it is still
good, run Setup. If not, replace
the RTC chip.

1-20 User’s Guide
1.8.3 Correcting Error Conditions
As a general rule, if an error message says "Press F1 to continue," it is
caused by a configuration problem, which can be easily corrected. An
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:
1. Run Setup. You must know the correct configuration values for
your system before you enter Setup, which is why you should
write them down when the system is correctly configured. An
incorrect configuration is a major cause of power-on error
messages, especially for a new system.
2. Remove the system unit cover. Check that the jumpers on the
system board and any expansion boards are set correctly.
3. If you cannot access a new disk, it may be because your disk is
not properly formatted. Format the disk first using the FDISK and
FORMAT commands.
4. Check that all connectors and boards are securely plugged in.
If you go through the corrective steps above and still receive an error
message, the cause may be an equipment malfunction.
If you are sure that your configuration values are correct and your
battery is in good condition, the problem may lie in a damaged or
defective chip.
In both cases, contact an authorized service center for assistance.