American Megatrends MAN-758 User Manual

MegaRUM

Dual Pentium® II

PCI ISA Motherboard

User's Guide

MAN-758

6/5/97

© Copyright 1985-2010 American Megatrends, Inc.
All rights reserved.
American Megatrends, Inc.

5555 Oakbrook Parkway, Building 200,

Norcross, GA 30093

This publication contains proprietary information which is protected by copyright. No part of this publication may be reproduced,
transcribed, stored in a retrieval system, translated into any language or computer language, or transmitted in any form whatsoever
without the prior written consent of the publisher, American Megatrends, Inc.

Limited Warranty

Buyer agrees if this product proves to be defective, that American Megatrends, Inc. is only obligated to replace or refund the purchase
price of this product at American Megatrend's discretion according to the terms and conditions on the motherboard warranty card.
American Megatrends shall not be liable in tort or contract for any loss or damage, direct, incidental or consequential. Please see the
Warranty Registration Card shipped with this product for full warranty details.

Limitations of Liability

In no event shall American Megatrends be held liable for any loss, expenses, or damages of any kind whatsoever, whether direct,
indirect, incidental, or consequential, arising from the design or use of this product or the support materials provided with the product.

Trademarks

VESA is a registered trademark of the Video Electronics Standards Association.
Intel, Pentium. Pentium Pro, and Pentium II are registered trademarks of Intel Corporation.
MS-DOS, Microsoft Word, and Microsoft are registered trademarks of Microsoft Corporation. Microsoft
Windows, Windows NT, and Windows 95 are trademarks of Microsoft Corporation.
IBM, AT, XT, CGA, VGA, PS/2, OS/2, and EGA are registered trademarks of International Business Machines
Corporation.
Fujitsu is a registered trademark of Fujitsu America, Inc.
Motorola is a registered trademark of Motorola Corporation.
Hitachi is a registered trademark of Hitachi America, Ltd.
PNY is a registered trademark of PNY Corporation.
Oki is a registered trademark of Oki America, Inc.
NEC is a registered trademark of NEC Corporation.
Samsung is a registered trademark of Samsung Electronics Corporation.
Siemens is a trademark of Siemens Corporation.
Mitsubishi is a registered trademark of Mitsubishi Electronics of America.
Micron is a registered trademark of Micron Corporation.
SCO, Unix, and UnixWare are registered trademarks of the Santa Cruz Operation, Inc.
Toshiba is a registered trademark of Kabushiki Kaisha Toshiba.
All other brand and product names are trademarks or registered trademarks of their respective companies.

Revision History

6/5/97 Initial release of preliminary version.

MegaRUM PCI Motherboard User’s Guideii

Preface

To the OEM Thank you for purchasing the high performance American Megatrends

MegaRUM Dual Pentium II PCI ISA motherboard. This product is a state of the
art motherboard that includes the famous AMIBIOS. It is assumed that you
have also licensed the rights to use the American Megatrends documentation
for the American Megatrends MegaRUM motherboard.

This manual was written for the OEM to assist in the proper installation and
operation of this motherboard. This manual describes the specifications and
features of the MegaRUM PCI motherboard. It explains how to assemble a
system based on the MegaRUM PCI motherboard and how to use the
AMIBIOS that is specifically designed for this motherboard.

This manual is not meant to be read by the computer owner who purchases a
computer with this motherboard. It is assumed that you, the computer
manufacturer, will use this manual as a sourcebook of information, and that
parts of this manual will be included in the computer owner's manual.

Technical Support If an American Megatrends motherboard fails to operate as described or you

are in doubt about a configuration option, please call technical support at 770­246-8600.

Web Site We invite you to access the American Megatrends world wide web site at:

http://www.ami.com.

Preface iii

Packing List

Do not use 16 MB x 36 (64 MB) SIMMs that have 36 chips per SIMM.

excessive loading on the motherboard circuitry. If you must use 64

Do not use 70 ns SIMMs. The system memory timing cycle on this

You should have received the following:

•

a MegaRUM Dual Pentium II PCI ISA motherboard,

•

two serial cables,

•

one parallel cable,

•

one VGA cable,

•

two VGA driver diskettes for Windows 95 and Windows NT V3.5x,

•

5 SCSI driver diskettes,

•

a diskette containing the American Megatrends DMI Wizard 95 software utility,

•

The DMI Wizard 95 User’s Guide,

•

the SystemGuru User’s Guide,

•

4 diskettes containing the SystemGuru Server Management Software for Windows NT,

•

a Warranty Card, and

•

the American Megatrends MegaRUM Dual Pentium II PCI ISA Motherboard User's Guide.

Warning

This type of 16 MB SIMM does not work reliably because of

MB SIMMs, use only SIMMs that have 12 or 8 chips per SIMM.

motherboard are very sensitive. This motherboard does not work

reliably with 70 ns SIMMs.

MegaRUM PCI Motherboard User’s Guideiv

1 Hardware Installation

Overview

The American Megatrends MegaRUM PCI Dual Pentium II ISA motherboard
features include:

• two Intel Pentium II CPUs operating at 120, 133, 150, 166, 180, 200, 210, 233,

240, 266 MHz or higher speeds ,

• up to 1 GB of system memory on the motherboard,

• parity checking or ECC (Error Checking and Correction),

• PCI local bus throughput of 132 megabytes per second,

• two Ultra Wide SCSI channels operating at 40 MBs,

• specially designed for the American Megatrends RAID Upgrade controller

cards,

• onboard ATI Rage II PCI VGA controller with 2 MB of synchronous

graphics RAM,

• the American Megatrends SystemGuru server management software,

• two ISA expansion slots, and

•

six PCI expansion slots.

CPUs The MegaRUM motherboard will support all Intel Slot1 CPUs operating at 233

MHz, 266 MHz, or faster speeds.

PCI Bus Speed AMIBIOS automatically configures the PCI slots. The PCI slots are

synchronous with the CPU clock:

CPU External Clock Frequency PCI Expansion Slot Frequency

66 MHz 33 MHz
60 MHz 30 MHz

Cont’d

Chapter 1 Hardware Installation 1

Overview, Continued

Onboard I/O The MegaRUM motherboard includes:

• an onboard ATI Rage II PCI VGA controller with 2 MB of synchronous

graphics memory,

• two onboard Symbios Logic 53C875 SCSI controllers that provide 2 40

MBs ultra wide SCSI channels and one ultra wide/narrow SCSI channel,

• two 40-pin IDE connectors for 1 – 4 IDE drives,

• a 34-pin floppy drive connector,

• two serial port connectors,

• a 25-pin parallel port connector,

• a keyboard DIN connector,

• two 4-pin USB ports, and

•

a 9-pin berg mouse connector.

Server Management Software The American Megatrends SystemGuru server management

software is included with the MegaRUM motherboard. SystemGuru uses the
I2C interface to constantly monitor and report the CPU temperature, fan speed,
ECC memory errors, ambient temperature, CPU voltage, system voltage and
other user-specified system status information to any remote client computer.
See the American Megatrends SystemGuru User’s Guide for additional
information.

Onboard PCI VGA The PCI VGA on the MegaRUM motherboard is supported by the ATI 3D

RAGE II 264GT PCI Graphics Controller chip. The PCI VGA features are:

•

2 MB SGRAM (not upgradable),

•

a VGA cable is included, and

•

video drivers for Windows 95 and Windows NT will be provided.

You can download video drivers for all other operating systems from the ATI
BBS at 905-764-9404. Make sure you load the ATI 3D RAGE II drivers from the
diskette provided. Windows 95 auto detection tries to load the ATI Mach 64
drivers, which will not function properly.

MegaRUM PCI Motherboard User’s Guide2

MegaRUM PCI Dimensions

The motherboard is approximately 12.25” by 13.8”. The motherboard height
restrictions are shown below:

Warning

This motherboard contains sensitive electronic components

that can be easily damaged by static electricity. Follow the

antistatic instructions carefully to ensure correct installation

and to avoid damage.

Chapter 1 Hardware Installation 3

MegaRUM PCI Motherboard Layout

MegaRUM PCI Motherboard User’s Guide4

Step 1 Unpack the Motherboard

Step Action

1 Inspect the cardboard carton for obvious damage. If

damaged, call 770-246-8645. Leave the motherboard in its
original packing.

2 Perform all unpacking and installation procedures on a

ground-connected anti-static mat. Wear an anti-static
wristband grounded at the same point as the anti-static
mat. Or use a sheet of conductive aluminum foil grounded
through a 1 megohm resistor instead of the anti-static mat.
Similarly, a strip of conductive aluminum foil wrapped
around the wrist and grounded through a 1 megohm
resistor serves the same purpose as the wristband.

3 Inside the carton, the motherboard is packed in an

anti-static bag, and sandwiched between sheets of
sponge. Remove the sponge and the anti-static bag. Place
the motherboard on a grounded anti-static surface
component side up. Save the original packing material.

4 Inspect the motherboard for damage. Press down on all

ICs mounted in sockets to verify proper seating. Do not
apply power to the motherboard if it has been damaged.

5 If the motherboard is undamaged, it is ready to be

installed.

Set Jumpers Set all jumpers and install the CPU before placing the motherboard in the

chassis.

Avoid Static Electricity

Static electricity can damage the motherboard and other computer components.
Keep the motherboard in the anti-static bag until it is to be installed. Wear an
anti-static wrist grounding strap before handling the motherboard. Make sure
you stand on an anti-static mat when handling the motherboard.

Avoid contact with any component or connector on any adapter card, printed
circuit board, or memory module. Handle these components by the mounting
bracket.

Chapter 1 Hardware Installation 5

Step 2 Configure CPU Speed

If using two CPUs with different speed ratings, set the motherboard jumpers to
the lower CPU speed. J21 and J24 select the CPU speed. The drawings on the
next screens show how J24 and J21 should look for each possible CPU speed:

CPU Speed J21 J24

120MHz OPEN Short Pins 1-2,

133 MHz Shorted Short Pins 1-2,

150 MHz OPEN Short Pins 3-4

166 MHz Shorted Short Pins3-4

180 MHz OPEN Short Pins 1-2

200 MHz Open Short Pins 1-2

210 MHz OPEN Short Pin 5-6
233 MHz Shorted Short Pin 5-6
240 MHz OPEN Short Pins 1-2

266 MHz Shorted Short Pins 1-2

Short Pins 3-4
Short Pins 5-6
Short Pins 7-8

Short Pins 3-4
Short Pins 5-6
Short Pins 7-8

Short Pins 5-6
Short Pins 7-8

Short Pins 5-6
Short Pins 7-8

Short Pins 5-6
Short Pins 7-8

Short Pins 5-6
Short Pins 7-8

Short Pin 7-8
Short Pin 7-8

Short Pins 3-4
Short Pins 7-8

Short Pins 3-4
Short Pins 7-8

Important

Please contact American Megatrends technical support at

770-246-8645 to support a CPU running at other speeds.

Cont’d

MegaRUM PCI Motherboard User’s Guide6

Step 2 Configure CPU Speed, Continued

Cont’d

Chapter 1 Hardware Installation 7

Step 2 Configure CPU Speed, Continued

MegaRUM PCI Motherboard User’s Guide8

Step 3 Configure CPU Voltage

J5 and J15 Each CPU can be independently set to the correct CPU core voltage. J5 sets the

voltage for the CPU in CPU Slot1. J15 sets the voltage for the CPU in Slot2.

Core CPU Voltage J5 and J15 Setting

3.50V Short Pins 3-4

3.40V Short Pins 3-4

3.3V (Factory Setting) Short Pins 3-4

3.2V Short Pins 3-4

3.1V Short Pins 3-4

3.0V Short Pins 3-4

2.9V Short Pins 3-4

2.8V Short Pins 3-4

2.7V Short Pins 5-6

2.6V Short Pins 5-6

2.5V Short Pins 5-6

2.4V Short Pins 5-6

2.3V Short Pins 7-8

2.2V Short Pins 7-8

2.1V Short Pins 9-10

2.05V Short Pins 1-2

2.0V Short Pins 1-2

1.95V Short Pins 1-2

1.90V Short Pins 1-2

1.85V Short Pins 1-2

1.8V Short Pins 1-2

No CPU None

Short Pins 5-6
Short Pins 7-8

Short Pins 9-10

Short Pins 5-6
Short Pins 7-8

Short Pins 5-6

Short Pins 9-10

Short Pins 5-6
Short Pins 7-8

Short Pins 9-10

Short Pins 7-8

Short Pins 9-10

Short Pins 7-8

Short Pins 9-10

Short Pins 7-8

Short Pins 9-10

Short Pins 9-10

Short Pins 3-4
Short Pins 5-6
Short Pins 7-8

Short Pins 9-10

Short Pins 3-4
Short Pins 5-6
Short Pins 7-8

Short Pins 3-4
Short Pins 5-6

Short Pins 9-10

Short Pins 3-4
Short Pins 5-6

Short Pins 3-4
Short Pins 7-8

Short Pins 9-10

Short Pins 3-4
Short Pins 7-8

Chapter 1 Hardware Installation 9

Step 4 Install Additional Voltage Regulator

One Voltage Regulator Module (VRM) is shipped with every MegaRUM
motherboard. You need another VRM if you install two CPUs. You can order
VRMs for Intel Pentium II CPUs from:

Manufacturer Part Number AMI Part Number

VXI 073-20715-02 MDL-P681-V5A140

Corsair SPX560KM MDL-P681-V5A140

MegaRUM PCI Motherboard User’s Guide10

Step 5 Connect CPU Fans

J1, J7, and

J23 pinout

J1 and J7 (shown below) are 3-pin bergs that connect the fan on the CPU heat
sink to the motherboard power. J1 is the CPU fan connector for the CPU in CPU
Slot1. J7 is the CPU fan connector for the CPU in CPU Slot2.

Ground

Pin 1

+12V

Fan Sense

All Pentium II CPUs are shipped with a heat sink and a CPU fan. The
connector from the CPU fan usually has three leads (has red, yellow, and black
leads). Connect the Red lead to Pin 3 (+12V). Make sure that you use fans
that have 3 leads . The 3rd (yellow) lead should provide a tachometer output to
permit the fan speed to be monitored by the onboard server management
hardware. If you must use fans with only 2 leads, connect the red lead to Pin 3.

J23 Chassis Fan J23 is a 3-pin berg located near the VRM for the CPU 2 socket. The pinout is

the same for J23 as it is for J1 and J7. J23 provides +12V power to the main
chassis fan. The chassis fan should provide a tachometer output on Pin 3 so it
can be monitored by the onboard server management hardware.

Step 6 Install CPU

The Pentium II CPUs are on Intel Slot1 adapter cards. Insert the Slot1 cards into
the CPU card sockets on the motherboard. The CPU Slot1 sockets are below
the SIMM sockets.

Warning

Improper CPU installation can damage the CPU and the

motherboard. You must follow the procedures in this section

exactly as documented. Make sure you wear an antistatic
wristband while installing the CPU. Follow all antistatic

procedures.

Chapter 1 Hardware Installation 11

Step 7 Install Memory

System Memory There are eight 32-bit SIMM (Single Inline Memory Module) sockets. System

memory must be populated one bank at a time. Each bank has two sockets.
Each bank must be populated with the same type of SIMM. If a 4 MB SIMM is

installed in the first socket in Bank0, then the same type of 4 MB SIMM must
be installed in the second Bank0 SIMM socket. The minimum amount of
system memory supported by the MegaRUM PCI is 8 MB. Each socket can
hold one SIMM. You can use:

•

1 MB x 32 (or 36),

•

2 MB x 32 (or 36),

•

4 MB x 32 (or 36),

•

8 MB x 32 (or 36),

•

16 MB x 32 (or 36), or

•

32 MB x 32 (or 36) SIMMs.

The MegaRUM motherboard will support 128 MB SIMMs when they become
available, permitting up to 1 GB of system memory to be installed on the
motherboard.

Fast Page Mode, EDO, and Burst EDO SIMMs cannot be mixed. The
motherboard supports SIMMs operating at 60 or 70 ns (RAS access time). Set
the Chipset Setup DRAM Speed (ns) option correctly.

Memory Display System memory is reported by AMIBIOS as it boots and again when the

AMIBIOS System Configuration Screen is displayed just before the operating
system boots. The memory displayed by AMIBIOS on the System
Configuration Screen is 384 KB less than the total memory installed.

Cont’d

MegaRUM PCI Motherboard User’s Guide12

Step 7 Install Memory, Continued

Select SIMMs SIMMs must meet the following specifications:

Parameter Specification

Page Mode FAST

Refresh CAS before RAS

CAC

SIMM Part Numbers

1 MB x 36 Micron MT12D136M-7
“ Mitsubishi MH1M36ADJ-7
“ PNY P361000-70
“ Motorola MCM36100AS-70
“ Oki MSC2355-70YS12
“ Samsung KMM5361000AV-7
2 MB x 36 PNY P362000-70
“ Samsung EMM53620036-70
4 MB x 36 Micron MT12D436M-7
“ Mitsubishi MH4M36SAJ-7
“ Motorola MCM36400S-70
“ PNY P364000-70
“ Samsung KMM5364100-7
8 MB x 36 Motorola MCM36800S-70
“ PNY P368000-707
“ Samsung KMM5368100-7
16 MB x 36 Samsung KMM53616000AKG-6

t

RAC

t

AA

t

RP

t

CPA

t

Type Manufacturer Part Number

≤
≤
≤

70 ns

≤

20 ns
80 ns
45 ns

45 ns

Cont’d

Chapter 1 Hardware Installation 13

Step 7 Install Memory, Continued

Installing SIMMs The four SIMM sockets on the motherboard can be filled with either 1 MB x 32

(or 36), 2 MB x 32 (or 36), 4 MB x 32 (or 36), 8 MB x 32 (or 36), or 16 MB x 32 (or

36) SIMMs.
Place the motherboard on an anti-static mat. With the component side of the

SIMM facing you, firmly push the SIMM into the socket at an angle, then push
it up. When properly inserted, the SIMM clicks into place as the latching pins
engage. The SIMM installation process is shown below:

MegaRUM PCI Motherboard User’s Guide14

Step 8 Install the Motherboard

The motherboard mounting hole pattern is shown below. Standoffs and
mounting screws are not supplied with the motherboard. The chassis
manufacturer should supply these parts.

Step Action

1 Place the chassis on an anti-static mat. Connect the chassis to ground to avoid static

damage during installation. Connect an alligator clip with a wire lead to any
unpainted part of the chassis. Ground the other end of the lead at the same point as
the mat and the wristband.

2 Rotate the chassis so the front is to the right, and the rear is to the left. The side facing

you is where the motherboard is mounted. The power supply is mounted at the far end
of the chassis.

3 Hold the motherboard, component-side up, with the edge with the SIMM sockets

toward you and the edge with the power supply connector away from you. The
keyboard, mouse, and video connectors should be to the left.

4 Carefully slide the motherboard into the chassis. Make certain the edge connectors fit

the ports in the rear of the chassis. The motherboard should rest level with the
chassis.

5 Place the mounting screws in the holes provided and tighten them. If necessary, shift

the motherboard slightly to align the mounting holes on the motherboard with the
holes on the chassis,

If using metallic screws, make sure you use them only in

Warning

the plated mounting holes.

If using metallic screws, make sure the head of the screw

fits completely inside the plated mounting holes.

Chapter 1 Hardware Installation 15

Step 9 Attach Cables

Connectors The MegaRUM PCI motherboard includes many connectors. Connection

instructions, illustrations of connectors, and pinouts are supplied in the
following pages. A list of all connectors described in this section follows:

Connector

Power supply connectors P1, P2, P3, and P4
Drain CMOS RAM power – J35
Keyboard connector J12
PS/2 mouse connector J2
Chassis intrusion LED – J29
External SMI connector – J18
Disable onboard VGA – J14
Hardware reset switch J28
Speaker J46
SCSI activity LED – J40
Keyboard lock connector J41
Turbo LED connector J33
IDE LED connector J38
USB port 1 connector J19
USB port 2 connector J20
System override – J47
AMI-specific VGA cable – J16
Disable VGA interrupt – J13
Serial port 1 connector J9
Serial port 2 connector J8
Parallel port connector J3
Floppy connector J4
IDE channel 0 connector J10
IDE channel 1 connector J11
SCSI channel 1 (Wide) – J44
SCSI channel 1 (Narrow) – J36
SCSI channel 2 (Wide) – J45
SCSI channel 2 (Narrow) – J37

Cont’d

MegaRUM PCI Motherboard User’s Guide16

Step 9 Attach Cables, Continued

Cable Connector Ends When connecting chassis connectors to the motherboard, make sure to

connect the correct connector end. Most connector wires are color-coded.
Match the color of the wires leaving the switch or LED to the same pin on the
connector end. There may be more than one connector with the same color-
coded wires. If so, follow the wire to the switch or LED. All motherboard
components are outlined by a white rectangular box with a broad arrow at one
end. Pin 1 is always at the arrow end of the white outlined box, as shown
below:

Chapter 1 Hardware Installation 17

Step 9 Attach Cables, Continued

Connect Power Supply The power supply should match the physical configuration of the

chassis. Make sure the power switch is off before assembly.
Before attaching all components, make sure the proper voltage has been

selected. Power supplies often can run on a wide range of voltages and must
be set (usually via a switch) to the proper range. Use at least a 450 watt power
supply, which should have built-in filters to suppress radiated emissions.

Connect Power Cables Attach the power supply cables to the power connector (P1 and P3) on

the motherboard. AT-compatible power supplies have two six-pin connectors,
attached as shown below. The six-pin connector on the power cable with three
red wires and two black wires is attached to P3. The other connector on the end
of the power cable is attached to P1.

Cont’d

MegaRUM PCI Motherboard User’s Guide18

Step 9 Attach Cables, Continued

Power Connector Keys The power connectors are keyed to prevent incorrect installation. The

keys on the connector must be cut to fit on some power supplies, as shown
below.

P1 Pinout

Pin Description

1 Power Good (Orange wire) (Not used)
2 VCC (Red wire)
3 +12 Volts (Yellow wire)
4 -12 Volts (Blue wire)
5 Ground (Black wire)
6 Ground (Black wire)

P3 Pinout

Pin Description

1 Ground (Black wire)
2 Ground (Black wire)
3 -5 Volts (White wire)
4 VCC (Red wire)
5 VCC (Red wire)
6 VCC (Red wire)

Cont’d

Chapter 1 Hardware Installation 19

Step 9 Attach Cables, Continued

P2 Pinout

Pin Description

1 5V
2 5V
3 5V
4 Ground
5 Ground
6 Ground

P4 Pinout

Pin Description

1 3V
2 3V
3 3V
4 Ground
5 Ground
6 Ground

J35 Erase Password J35 is a 2-pin berg that can be used to erase the contents of CMOS RAM,

where all system configuration information is stored.
If you forget the AMIBIOS password, you can place a shorting bridge on J35

for a few seconds to erase the old password (and all system configuration
information as well). You must then reboot the computer, run AMIBIOS Setup,
and restore all system configuration information. The J35 settings are:

CMOS Drain J35 Setting

Normal operation (factory setting). OPEN

The contents of CMOS RAM are destroyed. Shorted

Cont’d

MegaRUM PCI Motherboard User’s Guide20

Step 9 Attach Cables, Continued

J12 Keyboard Connector The keyboard connector is a 6-pin DIN socket. The pinout is shown

below.

Pin Assignments

1 Keyboard clock
2 Keyboard data

3, 6 Not used

4 Ground
5 VCC

Connect Mouse Cable The mouse connector (J2) is a 10-pin berg. The mouse cable is the same as

the serial cable in the motherboard. Two serial cables are shipped with the
motherboard. Use one of these cables for the mouse, or make your own cable.
The pinout is:

Pin Description Pin Description

1 Mouse Clock 2 N/C
3 N/C 4 N/C
5 N/C 6 VCC
7 N/C 8 Mouse Data
9 Ground 10 N/C

J29 Chassis Door Intrusion J29 is a 2-pin berg that can be used to attach a wire to the chassis

door intrusion connector, if the chassis has this feature. The logic must be set
so that Pin 1 and Pin 2 are shorted when the chassis door is closed and open
when the chassis door is opened.

J18 External SMI J18 is a 3-pin berg. An external SMI (System Management Interrupt) source

can be connected to J18. When an external SMI needs to generate an SMI to
the system, Pin 1 must be shorted to Pin 2 (as a pulse).

Cont’d

Chapter 1 Hardware Installation 21

Step 9 Attach Cables, Continued

J28 Reset Switch Connector J28 is a two-pin single-inline berg that is attached via a cable to an

externally-mounted reset switch.
When the reset switch is pressed, the system performs a hard reset. Pin 1 is

ground and Pin 2 is Hard Reset.

J46 Speaker Connector J46 is a four-pin single-inline berg that is optionally attached via a cable

to a standard system speaker. AMIBIOS signals hardware problems through
the speaker. Pin 1 on the motherboard is identified by the arrow on the white
box around the berg. The MegaRUM PCI motherboard also has a built-in
speaker mounted on the motherboard.

Pin Description

1 Data Out
2 Key
3 N/C
4 VCC

J40 SCSI Activity J40 is a 4-pin berg that attaches to a cable connected to the SCSI activity

indicator.

J47 System Override J47 is a 2-pin berg that attached to a system override switch.

Cont’d

MegaRUM PCI Motherboard User’s Guide22

Step 9 Attach Cables, Continued

J41 Keyboard Lock J41 is a 5-pin single-inline berg that is attached via a cable to the keyboard

lock connector (or separate keyboard lock and Power LED connectors). The
computer chassis may not include the keyboard lock and Power LED on a
single connector. The keyboard lock allows the user to lock the keyboard,
protecting the system from unauthorized use. Pin 1 on the motherboard is
identified by the broad arrow.

Pin Description

1 VCC
2 Ground
3 Ground
4 Keyboard Lock (KBDINH)
5 Ground

J33 Turbo LED J33 is a 2-pin berg that is attached via a cable to the externally-mounted bipolar

Turbo LED. The LED lights when the motherboard is running at high speed.

J38 IDE LED J38 is a two-pin berg that is attached via a cable to the externally-mounted IDE

Activity LED. This LED lights when the IDE drive is running.

Warning

In some IDE drives, you may have to disable the

IDE LED mounted on the drive by changing a

jumper or setting a switch on the IDE drive itself,

before the IDE drive sends a signal to J34.

Cont’d

Chapter 1 Hardware Installation 23