Compaq AlphaServer DS20 Service Manual

AlphaServer DS20

Service Manual

Order Number: EK–AS140–SV. A 01

This manual is for anyone who services this system. It includes
troubleshooting information, configuration rules, and instructions for
removal and replacement of field-replaceable units.

Compaq Computer Corporat ion

Notice

The in fo rmatio n in this p ublication is subject to ch ange w ithout n otice.
COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECHNICAL

OR EDITORIAL ERRORS OR OMISSIONS CONTAINED HEREIN, NOR FOR
INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE
FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL.

This publication c ont ai ns in formation protecte d by copyright. No par t of this p ubl ic at ion may b e
photocopied or repr oduced in any form without prior written consent from Compaq Co mp ut er
Corporation.

The software desc ri bed i n th is do cument is furnished under a license agreement or
nondisclosure agr eement and may be used or copied only in acco rda nce with the terms of the
agreement.

© 1999 Digital Equipment Corporat ion.
All rights res e rved. P rinted in the U. S .A.
COMPAQ and the Compaq logo are trademarks or registere d tr adem arks of Compaq Computer

Corporation. A lphaS erver, DIGITAL, OpenVMS, and StorageWorks are trademarks or
registered trademarks of Digital Equ ip me nt Corporation. Micros oft, Windows, and Windows
NT are registere d tr ademarks of Microsoft Corporat ion. U N IX is a regi stered tradem ar k in th e
U.S. and other countr ie s, licens ed exclusively through X/Open Company Ltd. Other produc t
names mentioned herein may be trademarks and/o r reg is tered trademarks of their respect iv e
companies.

Digital Equipmen t Corporation now ow ned by C ompaq Compu ter Co rporation.
FCC Notice: The equipment described in thi s ma nual generates, use s, and may emit radio

frequency energ y. T he equipment has been typ e te st ed and f ound to comply with the l im i ts for a
Class A digital device pursuant to Part 15 of FCC Rules, w hich are de si gned to provide
reasonable prote ct ion a gainst such radio freq uency interferenc e. O pera ti on of thi s equ ipment in
a residential area may cause inter fe rence, in which case the user at his own expense will be
required to take w hat ever measures a re re quired to correc t the interference.

Shielded Cables: If shielded cables have been supplied or specified, they mus t be us ed on t he
syste m in order to mainta in internatio n al regulatory compliance.

Warning! This is a Clas s A produ ct. In a do mestic environment this product may cause radio
interference, in wh i ch case the user may be required to take adequate measures.

Achtung! Dieses ist ein Gerä t de r Funk st örgrenzwertkla ss e A . In Wohnbereichen können bei
Betrieb dieses Geräte s Rundfunkstörungen auftreten, in welchen Fäl le n der Be nut zer für
entsprechend e G egenmaßnahmen ve rantwortlich ist.

Avertissement! Cet appareil est un appareil de Classe A. Dans un environnement résidentiel,
cet appareil peut provoquer des brouillages radioélectriques. Dans ce cas, il peut être demandé à
l'utilisateur de prendre les mesures appropriées.

Contents

Preface ........................................................................... ix

Chapter 1 System Overview

1.1 System Enclosure.....................................................................................1-2

1.2 Operator Control Panel and Drives........................................................... 1-4

1.3 System Consoles ......................................................................................1-6

1.4 System Architecture................................................................................. 1-8

1.5 CPU Types.............................................................................................1-10

1.6 Memory .................................................................................................1-12

1.7 Memory Addressing and Data Location ..................................................1-14

1.8 System Board.........................................................................................1-16

1.8.1 Cross-Bar Switch and System Components ......................................1-18

1.8.2 I/O Subsystem.................................................................................1-20

1.8.3 System Board Switchpacks..............................................................1-22

1.9 Server Feature Module...........................................................................1-24

1.9.1 Power Control Logic .......................................................................1-26

1.10 Power C ir cuit and C o ver Interlock..........................................................1-28

1.11 Power Supply.........................................................................................1-30

1.12 Power Up/Down Sequence.....................................................................1-32

1.13 TIG Bus.................................................................................................1-34

1.14 Maintenance Bus (I

1.15 StorageWorks Drives.............................................................................. 1-38

2

C Bus).....................................................................1-36

Chapter 2 Troubleshooting

2.1 Troubleshooting During Power-Up...........................................................2-2

2.2 Control Panel Display and Troubleshooting..............................................2-4

2.3 Power-Up Display and Troubleshooting....................................................2-6

2.4 Running Diagnostics — Test Command ...................................................2-8

2.5 Testing an Entire System..........................................................................2-9

2.6 Other Useful Console Commands...........................................................2-11

2.7 Troubleshooting with LEDs....................................................................2-12

2.8 Compaq Analyze....................................................................................2-14

2.8.1 Compaq Analyze Graphics Interface (GUI)......................................2-14

2.8.2 Description of the Error...................................................................2-16

2.9 Releasing Secure Mode..........................................................................2-20

iii

Chapter 3 Error Registers

3.1 Ibox Status Register - I_STAT..................................................................3-2

3.2 Memory Management Status Register – MM_STAT.................................3-3

3.3 Dcache Status Register – DC_STAT.........................................................3-5

3.4 Cbox Read Register..................................................................................3-7

3.5 Miscellaneous Register (MISC) ................................................................3-9

3.6 Device Interrupt Request Register (DIRn, n=0,1).................................... 3-12

3.7 Pchip Error Register (PERROR).............................................................3-13

3.8 Failure Register......................................................................................3-16

3.9 Funct i o n R egiste r...................................................................................3-18

Chapter 4 Removal and Replacement

4.1 System Safety.......................................................................................... 4-1

4.2 FRU List..................................................................................................4-2

4.3 System Access .........................................................................................4-6

4.4 CPU Removal and Replacement............................................................... 4-8

4.5 Memory Module Removal and Replacement..................................4-10

4.6 System Board Removal and Replacement...............................................4-12

4.7 PCI/ISA Option Removal and Replacement ............................................4-14

4.8 Server Feature Module Removal and Replacement..................................4-16

4.9 Power Supply Removal and Replacement............................................... 4-18

4.10 Power Harness Removal and Replacement..............................................4-20

4.11 Power Transition Module Removal and Replacement..............................4-22

4.12 Auxiliary Fan Removal and Replacement...............................................4-24

4.13 System Fan Removal and Replacement...................................................4-26

4.14 Cover Interlock Removal and Replacement............................................. 4-28

4.15 Operator Control Panel Removal and Replacement................................4-30

4.16 CD-ROM Removal and Replacement..................................................... 4-32

4.17 Floppy Removal and Replacement..........................................................4-34

4.18 SCSI Disk Removal and Replacement....................................................4-36

4.19 StorageWorks Backplane Removal and Replacement..............................4-38

4.20 StorageWorks UltraSCSI Bus Extender Removal and Replacement.........4-40

Appendix A Halts, Console Commands, and Environment
Variables

A.1 Halt Button Functions..............................................................................A-2

A.2 Using the Halt Button..............................................................................A-3

A.3 Ha lt Assertion .........................................................................................A-4

A.4 Summary of SRM Console Commands....................................................A-6

A.5 Summary of SRM Environment Variables...............................................A-8

A.6 Recordi n g Envir o n ment Va r iables.........................................................A-10

iv

Appendix B Managing the System Remotely

B.1 RCM Overview.......................................................................................B-2

B.2 First-Time Setup.....................................................................................B-3

B.2.1 Using RCM Locally or with a Modem on COM1...............................B-4

B.3 RCM Commands.....................................................................................B-5

B.4 Using the RCM Switchpack...................................................................B-10

B.5 Troubleshooting Guide..........................................................................B-13

Appendix C Firmware Update

C.1 Updating Firmware and Consoles............................................................C-2

C.1.1 Updating Firmware from the CD-ROM....................................................C-4

C.1.2 Updating Firmware from Floppy Disk — Creating th e Diskettes.............. C-8

C.1.3 Updating Firmware from Floppy Disk — Performing the Update........... C-10

C.1.4 Updating Firmware from a Network Device........................................... C-14

C.1.5 LFU Commands.................................................................................... C-18

Examples

1–1 Show Memory............................................................................................1-15

2–1 Power-Up Display........................................................................................2-6

2–2 Test Command Syntax..................................................................................2-8

2–3 Sample Test Command.................................................................................2-9

2–4 Show Power............................................................................................... 2-11

2–5 Show Memory............................................................................................2-11

2–6 Compaq Analyze Error Report....................................................................2-16

2–7 Releasing/Reestablishing Secure Mode.......................................................2-20

B–1 Invoking and Leaving RCM Locally ............................................................ B-4

C–1 Starting LFU from the SRM Console ........................................................... C-2

C–2 Booting LFU from the CD-ROM ................................................................. C-3

C–3 Updating Firmware from the CD-ROM ........................................................ C-4

C–4 Creating Update Diskettes on an OpenVMS System..................................... C-9

C–5 Updating Firmware from the Floppy Disk .................................................. C-10

C–6 Selecting AS1400FW to Update Firmware from the Internal Floppy Disk . . . C-13

C–7 Updating Firmware from a Network Device............................................... C-14

v

Figures

1-1 System Enclosure.........................................................................................1-2

1-2 Cover Interlock Circuit.................................................................................1-3

1-3 Control Panel Assembly...............................................................................1-4

1-4 Block Diagram.............................................................................................1-8

1-5 CPU Module Placement .............................................................................1-10

1-6 Memory Placement.................................................................................... 1-12

1-7 Contents of DIMMs ................................................................................... 1-14

1-8 Memory Configuration...............................................................................1-15

1-9 System Board.............................................................................................1-16

1-10 Cross-Bar Switch Data Block Diagram .......................................................1-18

1-11 PCI Block Diagram....................................................................................1-20

1-12 Switchpack Location..................................................................................1-22

1-13 Server Feature Module...............................................................................1-24

1-14 Power Control Logic..................................................................................1-26

1-15 Power Circuit Diagram...............................................................................1-28

1-16 Back of Power Supply and Location...........................................................1-30

1-17 Power Up/Down Sequence Flowchart.........................................................1-32

1-18 TIG Bus Block Diagram.............................................................................1-34

2

1-19 I

1-20 StorageWorks Drive Location ....................................................................1-38

2-1 Control Panel and LCD Display....................................................................2-4

2-2 CPU and Server Feature Module LEDs.......................................................2-12

2-3 Compaq Analyze Graphics Interface...........................................................2-14

4-1 Some of the FRU Locations..........................................................................4-2

4-2 Accessing the System...................................................................................4-6

4-3 Removing CPU Module ...............................................................................4-8

4-4 Removing Memory.................................................................................... 4-10

4-5 Removing System Board............................................................................4-12

4-6 Removing PCI/ISA Option .........................................................................4-14

4-7 Removing Server Feature Module ..............................................................4-16

4-8 Removing Power Supply............................................................................4-18

4-9 Removing Power Harness........................................................................... 4-20

4-10 Removing Power Transition Module ..........................................................4-22

4-11 Remove Auxiliary Fan Removal.................................................................4-24

4-12 Removing System Fan................................................................................4-26

4-13 Removing Cover Interlock..........................................................................4-28

4-14 Removing OCP..........................................................................................4-30

4-15 Removing CD-ROM.................................................................................. 4-32

4-16 Removing Floppy.......................................................................................4-34

4-17 Removing StorageWorks Disk....................................................................4-36

4-18 Removing StorageWorks Backplane...........................................................4-38

C Bus Block Diagram.............................................................................. 1-36

vi

4-19 Removing StorageWorks UltraSCSI Bus Extender...................................... 4-40

B-1 RCM Connections ...................................................................................... B-3

B-2 Location of RCM Switchpack on Server Feature Module .......................... B-10

C–1 Starting LFU from the AlphaBIOS Console.................................................C-2

Tables

1-1 PCI Slot Numbering....................................................................................1-21

1-2 Switchpack 2............................................................................................... 1-23

1-3 Switchpack 3............................................................................................... 1-23

1-4 Remote Control Switch Functions ...............................................................1-25

2-1 Control Panel Display................................................................................... 2-5

2-2 Types of Errors ...........................................................................................2-19

3-1 Ibox Status Register......................................................................................3-2

3-2 Memory Management Status Register............................................................3-4

3-3 Dcache Status Register..................................................................................3-6

3-4 Cbox Read Register.......................................................................................3-7

3-5 Miscellaneous Register................................................................................3-10

3-6 Device Interrupt Request Register ...............................................................3-12

3-7 Pchip Error Register....................................................................................3-14

3-8 Failure Register...........................................................................................3-17

3-9 Function Register........................................................................................3-19

4-1 Field-Replaceable Unit Part Numbers............................................................4-3

A-1 Results of Pressing the Halt Button...............................................................A-2

A-2 Summary of SRM Console Commands.........................................................A-6

A-3 Environment Variable Summary...................................................................A-8

A-4 Environment Variables Worksheet..............................................................A-10

B-1 RCM Command Summary............................................................................B-5

B-2 RCM Status Command Fields ....................................................................... B-9

B-3 RCM Troubleshooting ................................................................................ B-13

C–1 File Locations for Creating Update Diskettes on a PC....................................C-8

C–2 LFU Command Summary........................................................................... C-18

vii

Preface

Intended Audience

This manual is written for the customer service engineer.

Document Structure

This manual uses a structured document ation desig n. Topics are organ ized into small
sections for efficient online and printed reference. Each topic begins with an abstract,
followed by an illustration or example, and ends with descriptive text.

This manual has four chapters and three appendixes, as follows:

• Chapter 1, System Overview, introduces the Compaq AlphaServer DS20

system. It describes each system component.

• Chapter 2, Trouble shoo ting , describes troubleshooting during power-up and

booting, as well as the test command.

• Chapter 3, Error Registers, describes the error registers used to hold error

information.

• Chapter 4, Removal and Replacement, describes removal and replacement

procedures for field-replaceable units (FRUs).

• Appendix A, Halts, Co nsole Commands, a nd Enviro nment Vari a bles,

summarizes the commands used to examine and alter the system configuration.

• Appendix B, Managing t he System Remotel y, describes how to use the Remote

Console Manager (RCM) to monitor and control the system remotely.

• Appendix C, Firmware Upda te, describes how to update system firmware.

ix

Documentation Titles

Table 1 lists books in the documentation set.

Table 1 AlphaServer DS20 Documentation

Title Order Number

User and Installation Documentation Kit QZ–014AA–G8

User’s Guide EK–AS140–UG

Basic Installation EK–AS140–IN

Service Information

Service Manual EK–AS140–SV

Information on the Internet

Using a Web browser you can access the AlphaServer InfoCenter at:
http://www.digital.com/info/alphaserver/products.html
Access the latest system firmware either with a Web browser or via FTP as follows:

ftp://ftp.digital.com/pub/Digital/Alpha/firmware/

Interim firmware released since the last firmware CD is located at:

ftp://ftp.digital.com/pub/Digital/Alpha/firmware/interim/

x

Chapter 1

System Overview

The Compaq Alpha Server DS2 0 system c onsi sts of up to two CPUs, up to 4 Gbytes of
memory, 6 I/O slots, and up to 7 SCSI storage devices. AlphaServer DS20 systems

can be mounted in a standard 19” rack.
AlphaServer DS20 systems support OpenVMS, Compaq Tru64 UNIX, Windows NT,

and Linux.
Topics in this chapter include the following:

• System Enclosure

• Operator Control Panel and Drives

• System Consoles

• System Architecture

• CPU Types

• Memory

• Memory Addressing and Data Location

• System Board

• Server Feature Module

• Power Circuit and Cover Interlock

• Power Supply

• Power Up/Down Sequence

• TIG Bus

• Maintenance Bus (I

• StorageWorks Drives

2

C Bus)

System Overview 1-1

1.1 System Enclosure

The system has up to two CPU modules and up to 4 Gby tes of memory. A single
fast wide UltraSCSI Stora geW orks she lf prov i des up to 128 Gbyte s of storage.

Figure 1-1 System Enclosure

4

1

2

5

PKW-1402-98

3

6

1-2 AlphaServer DS20 Service Manual

The numbered callouts in Figure 1-1 refer to the system components.

➊

System card cage, which holds the system board and the CPU, memory, and
system I/O.

➋ PCI/ISA section of the system card cage.
➌ Operator contro l p anel assemb ly, which in cludes th e control p anel, the LC D

display, and the floppy drive.

➍ CD-ROM drive.
➎

Cooling section containing two fans and the server feature module.

➏ StorageWorks shelf.

Cover Interlock

The system has a single cover interlock switch tripped by the top cover.

Figure 1-2 Cover Interlock Circuit

Power

Server Feature Module

Switch

pack

Supply

Cover

Interlock

Push button

ON/OFF

OCP

DC_ENABLE_L

OCP

Connector

PK1405-99

NOTE: The cover interlock must be engaged to enable power-up.

To overr ide the cover inter lock, use a s u itable object to close the inter lock cir cuit.

Disk damage will result if the system is run with the top cover off.

Cover

Interlock

Switch

System Overview 1-3

1.2 Operator Control Panel and Drives

The control panel includes the On/Off, Halt, and Reset buttons and an LCD
display.

Figure 1-3 Control Panel Assembly

CD-ROM

Floppy

OCP Display

1

OCP display. The OCP display is a 16-character LCD that indicates status during
power-up and self-test. While the operating system is running, the LCD displays the
system type. Its controller is on the XBUS.

CD-ROM. The CD-ROM drive is used to load software, firmware, and updates. Its
controller i s on P CI1 on th e P C I backplane on the system b oa rd.

Floppy disk. The floppy drive is used to load software and firmware updates. The
floppy c ontrol ler is on the XBUS on the PCI backplane on the system b oard.

2

3

PKW-0501-97

1-4 AlphaServer DS20 Service Manual

➊ On/Off button. Powers the system on or off. When the LED to the right of the

button is lit, the power is on. The On/Off button is connected to the power
supplies through the system interlock and the RCM logic.

➋ Rese t but ton. Initializes the system.
➌ Halt button. When the Halt button is pressed, different results are manifest

depending upon the state of the machine.
The major function of the Halt button is to stop whatever the machine is doing

and return the system to the SRM console.
To get to the SRM console, for sy stems r u nni ng OpenVMS o r Compaq Tr u64

UNIX, press the Halt button.
To get to the SRM console, for systems running Windows NT, press the Halt

button and then press the Reset button. (Pressing the Halt button when the

system is running Windows NT causes a “halt assertion” flag to be set in the
firmware. When Reset is pressed, the console reads the “halt assertion” flag and
ignores environment variables that would cause the system to boot.)

The function of the Halt button is complex; it depends upon the state of the
machine when the button is pressed. See Section B.1 for a full discussion of the
Halt button.

System Overview 1-5

1.3 System Consoles

There are two console progra ms: the SRM consol e and the AlphaBIOS console.

SRM Console Prompt

On systems running the Compaq Tru64 UNIX or OpenVMS operating system, the
following console prompt is displayed after system startup messages are displayed, or
whenever the SRM console is invoked:

P00>>>

NOTE: The console prompt displays only after the entir e power-u p s equenc e is
complete. This can take up to several minutes if the memory is very large.

AlphaBIOS Boot Menu

On systems running the Windows NT operating system, the Boot menu is displayed
when the AlphaBIOS console is invoked:

1-6 AlphaServer DS20 Service Manual

SRM Console

The SRM console is a command-line interface used to boot the Compaq Tru64 UNIX
and OpenVMS operating systems. It also provides support for examining and
modifying the system state and configuring and testing the system. The SRM console
can be run from a serial terminal or a graphics monitor.

AlphaBIOS Console

The AlphaBIOS console is a menu-based interface that supports the Microsoft
Windows NT operating system. AlphaBIOS is used to set up operating system
selections, boot Windows NT, and display information about the system configuration.
The ISA Configuration Utility and the RAID Standalone Configuration Utility are run
from the AlphaBIOS console. AlphaBIOS runs on either a serial terminal or graphics
terminal. Windows NT requires a graphics monitor.

Environment Variables

Environment variables are software parameters that define, among other things, the
system configuration. They are used to pass information to different pieces of
software running in the system at various times . The os_type environment variable,
which can be set to VMS, UNIX, or NT, determines which of the two consoles is used.
The SRM console is always brought into memory, but AlphaBIOS is loaded if os_type
is set to NT and the Halt LED is not lit .

Refer to Appendix A of this guide for a list of the environment variables used to
configure a system.

Refer to your system User’s Guide for information on setting environment variables.
Most environment variables are stored in the NVRAM area of the flash ROM on the

system board. It is recommended that you keep a record of the environment variables
for each system that you service. Some environment variable settings are lost when a
module is swapped and must be restored after the new module is installed. Refer to
Appendix A for a convenient worksheet for recording environment variable settings.

System Overview 1-7

1.4 System Architecture

1 or 2

PKW1400-98

An Alpha microprocessor chi p is use d in this system. The CPU, memo ry, and the
I/O modules are physically connected to the system board and logically connected
through a switch-based interconnect implemented in a cross-bar switch chipset.

Figure 1-4 Block Diagram

Command, Address, and Control lines for each Memory Array

C chip

Control lines for D chips

Probe/
Addr.

CMD/
Addr.

CPU 0

Probe/
Addr.

CMD/
Addr.

CPU 1

(optional)

B cache

CPU
Data
Bus

CAPbus

P chip

P chip

PAD
Bus

64 bit PCI

8 D chips

64 bit PCI

Up to 2

Memory

Banks

Memory

Data

Bus

Memory

Banks

B cache

1-8 AlphaServer DS20 Service Manual

The AlphaServer DS20 is a switch-based interconnect system; it uses a cross-bar
switch chipset that allows data to move directly from place to place in the system. The
CPU, memory, and I/O devices physically connect to the system board and each has
one or two logical connections to the switch. The arrows on the block diagram shown
in Figure 1-4 indicate the flow of data, command/address, and control signals.

On the system board is:

• A system switch consisting of a control chip (C-chip) and 8 data chips (D-chips)

• Three buses to the D-chips: the memory data bus, the CPU data bus, and the

P-chip address and data bu s (PAD bus)

• One bus from the C-chip to the P-chips (CAP bus)

• Two 60 command/address and control connections between each CPU and the

C-chip: the command/a d dress li ne f rom the CPUs to the C-chi p and the probe
address lines from the C-chip to the CPUs

• A TIG bus connected to the C-chip

• Control lines from the C-chip to the D-chips

• Control, timing, and address lines from the C-chip to each memory array

• Two 64-bit PCI buses with three PCI option slots each

• One ISA bus bridged on PCI0 and two SCSI ports (unused at FRS) also on PCI0

(If an ISA option is used, PCI 1 slot 9 cannot be used for a PCI option.)

• One ISA to XBUS bridge to the built-in XBUS options

A fully configu red pe desta l syst em can have two CPUs, sixte en DIMMs, a total of six
I/O options, and seven 18 Gbyte UltraSCSI disks. Maximum memory is 4 Gbytes.
The I/O options can be all PCI options or five PCI options and a single ISA option.

Other major lines in the system are used for command, addresses, and control.
For information on CPUs, see Sectio n 1. 5.
For information on memory, see Sections 1.6 and 1.7.
There are two 64-bit PCI buses connected to the cross-bar switch chipset by two PAD

buses and a single CAP bus. Each bus has three PCI slots for I/O devices. PCI bus 0
has an ISA bridge and a SCSI adapter with two ports (not used) embedded on the bus.
A single ISA slot is available on PCI bus 0 that, when used, eliminates the use of one
PCI slot on PCI bus 1.

Logic and sensors on the system feature module monitor power status and the system
environment (temperature and fan speeds).

System Overview 1-9

1.5 CPU Types

There is a single CPU variant.

Figure 1-5 CPU Module Placement

1
3
1

DIMM Slo ts

3
0
2
0
2

D

Chip

D

Chip

C

Chip

D

ChipDChip

CPU 0

DIMM Slots

PCI 0 Slot 7
PCI 0 Slot 8
PCI 0 Slot 9
PCI 1 Slot 7
PCI 1 Slot 8
PCI 1 Slot 9

ISA S lo t

D

D

Chip

Chip

2
0
2
0
3
1
3
1

D

ChipDChip

P

ChipPChip

CPU 1

PKW1401A-98

1-10 AlphaServer DS20 Service Manual

Alpha Chip Composition

The Alpha 21264 chip uses 0.35 micron chip technology, has a transistor count of 15.2
million, consumes 50 watts of power, and is air cooled (a fan is on the chip). The
default cache system is write-back.

Chip Description

Unit Description

Instruction 64-Kbyte I-cache
Execution 4-way execution; four integer units, two of which can perform

memory address calculations for load and store instructions;
dedicated units for floating-point add, multiply, divide, and
square root operations.

Memory Merge logic, 64-Kbyte write-through first-level data cache,

bus interface unit that consists of two ports, one a 16-byte B­cache port and the other an 8-byte system port.

CPU Variants

Module Variant Clock Frequency Onboard Cache

KN310-Ax 500 MHz 4 Mbytes

CPU Configuration Rules

• The first CPU must be in CPU slot 0.

• Both CPUs must have the same Alpha chi p clo c k spee d selected.

Module LEDs

Description (read LEDs from right to left on the

LED Name

module)

2V_PWRGOOD_LED Normally on. Indicates the presence of 2.XV.
SROM_CLK_LED Normally off. Toggles on and off rapidly during the

SROM load phase.
DC_OK_LED Normally on. Indicates the presence of DC_OK.
CPU_SELF_TEST_LED Normally on. Indicates the status of self-test. If the LED

is off, there was an error or timeout after the SROM load.

System Overview 1-11

1.6 Memory

Memory consists of up to four memory options, each consisting of four DIMMs.
There are four option variants: 128 Mbytes, 256 Mbytes, 512 Mbytes, and 1
Gbyte.

Figure 1-6 Memory Placement

1
3
1

DIMM Slo ts

3

0

2

0

2

D

Chip

D

Chip

C

Chip

D

ChipDChip

CPU 0

DIMM Slots

PCI 0 Slot 7
PCI 0 Slot 8
PCI 0 Slot 9
PCI 1 Slot 7
PCI 1 Slot 8
PCI 1 Slot 9

ISA S lo t

D

Chip

2
0
2
0
3

1

3

1

D

Chip

D

ChipDChip

P

ChipPChip

CPU 1

PKW1401B-98

1-12 AlphaServer DS20 Service Manual

Memory Variants

Memory is organized on two 256 plus ECC bit buses. Each bus can hold up to two
memory banks (a memory option) made up of four DIMM modules. Memory can be
configured from a minimum of 128 Mbytes (1 MS340-BA) to 4 Gbytes (4 MS340­EA). All memory is synchronous.

DRAM

Number/

Option Size Module Type

option Size

MS340-BA 128 MB 54-25066-BA Synch. 36 4 x 32MB
MS340-CA 256 MB 54-25053-BA Synch. 36 4 x 64MB
MS340-DA 512 MB 54-25941-KA Synch. 36 4 x 128MB
MS340-EA 1 GB 54-25941-BA Synch. 36 4 x 256MB

Memory Operation

Two 256-bit memory buses transfer data between the cross-bar chipset switch and
main memory. Each DIMM bank, made up of four DIMM modules, provides the data,
or 256 bits p lus 32 ECC b its, of the 32 by tes transferred. Two modules in the b an k
provide the odd bytes of data, and the other two modules provide the even bytes of
data.

Memory Configuration Rules

In a system, memories of different sizes are permitted, but:

• A memory option consists of four DIMMs all of which must be the same size.

• Convention places the largest memory option in slots marked 0 on the system

board. See Figure 1-6.

• Memory options must be installed in slots designated for each bank. The first

bank goes into slots marked 0, the second bank into slots marked 1, and so on.

System Overview 1-13

1.7 Memory Addressing and Data Location

0

0

0

0

PK1488-98

Memory addressing is contiguous beginning with memory bank 0. The first
address of each bank is one above the ending address of the previous bank.
Data is located in DIMMs as described by Figure 1-7.

Figure 1-7 Contents of DIMMs

D
Chip

D
Chip

DIMM Slots

D
Chip

D
Chip

DIMM Contains

Bank 1 even b yt es 0, 2, 4, 6, 8, 10, 12, 14
Bank 3 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 1 even b yt es 16, 18, 20, 22, 24, 26, 28, 3
Bank 3 even b yt es 16, 18, 20, 22, 24, 26, 28, 3
Bank 0 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 2 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 0 even b yt es 16, 18, 20, 22, 24, 26, 28, 3
Bank 2 even b yt es 16, 18, 20, 22, 24, 26, 28, 3

C
Chip

D
Chip

D
Chip

Bank 2 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 0 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 2 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 0 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 3 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 1 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 3 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 1 odd bytes 1, 3, 5, 7, 9, 11, 13, 15

D
Chip

D
Chip

DIMM Slots

1-14 AlphaServer DS20 Service Manual

Memory Addressing

p

Sy

The first address of each bank is one above the ending address of the previous bank.
Examp le 1 –1 and Figure 1-8 show the starting address of each memory bank using

either the SRM console or AlphaBIOS.

Example 1–1 Show Memory

P00>>> show memory

Array # Size Base Addr

------- ---------- --------­ 0 128 MB 000000000
1 128 MB 008000000
2 128 MB 010000000
3 128 MB 018000000

Total Ba d Pa ge s = 0
Total Good Memory = 512 MBytes

P00>>>

Figure 1-8 Memory Configuration

Display System Configuration F1= Hel

Systemboard Configuration
Hard Disk Configuration
PCI Configuration
SCSI Configuration
ISA Configuration

Memory Configuration

Integrated Peripherals

æ

Bank 0: 128 MB (32 MB per DIMM)-- Starting Address = 0x000 00000
Bank 1: 128 MB (32 MB per DIMM)-- Starting Address = 0x800 00000
Bank 2: 128 MB (32 MB per DIMM)-- Starting Address = 0x100 00000
Bank 3: 128 MB (32 MB per DIMM)-- Starting Address = 0x180 00000

ESC =Exit

DIMM Contents

Figure 1-7 shows the data contents of each DIMM in memory. Odd data bytes are in
DIMMs below the cross-bar swi tch chip set , a nd the even data byte s are in the DIMMs
above the cross-bar switch chipset.

stem Memory Configuration

System Overview 1-15

1.8 System Board

r

r

The system board contains five major logic sections performing five major
system functio ns.

Figure 1-9 System Board

Even bytes
of all memory
banks

I/O

Connector s

Odd bytes
of all memory
banks

PCI 0 Slot 7
PCI 0 Slot 8
PCI 0 Slot 9
PCI 1 Slot 7
PCI 1 Slot 8
PCI 1 Slot 9

ISA Slot

1
3
1
3
0
2
0
2

D

Chip

Chip

2
0
2
0
3
1
3

1

D

Chip

D

D

Chip

C

Chip

D

ChipDChip

D

ChipDChip

P

ChipPChip

TIG
Pal

3 V Power
& Misc 3V

CPU 0

CPU 1

5 V Power
Speaker

Connectors

SCSI

CTRL

ISA

Bridge

Junk I/O

SCSI

Battery

Flash
ROM

Connector
RCM

Connector

Floppy
Connect o

IDE
Connect o

PK1491-98

1-16 AlphaServer DS20 Service Manual

Three major sections on the system board are:

• The cross-bar switch chipset and the system components attached to it (CPU(s),

memory, PCI chips, and the TIG bus)

• The power connections and voltage regulator

• The I/O subsystem

System Overview 1-17

1.8.1 Cross-Bar Switch and System Components







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8

The cross-bar switch chipset consists of a single control chip, the C-chip, and
eight data chips, the D-chips. Into and out of the D-chips are two system buses to
CPUs, two PAD buses to PCI chips, and two memory data buses that connect to
up to four memory banks.

Figure 1-10 Cross-Bar Switch Data Block Diagram

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1-18 AlphaServer DS20 Service Manual

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PK1489-9

Each type of bus in the system is unique:

• The two memory data buses operate in 256-bit mode passing two hex words (32

bytes) of data between memory and the D-chips per cycle. The bus operates at

83.3 MHz.

• The two CPU data buses operate in “64-bit mode” passing a quadword (8 bytes)

of data between CPU and the D-chips per cycle. Though the CPU data bus is
narrower than the memory data bus, it operates at four times the speed of the
memory data bus at 333 MHz.

• The single CAP bus is a 24-bit wide bidirectional bus that carries commands and

addresses and is also used for transmitting data to and from the C-chip CSRs and
the TIG bus.

• The two PAD buses operate in 32-bit mode passing 8 nibbles per cycle. Two

cycles are required to pass 8 bytes of data. The PAD bus runs at 83.3 MHz.

• The TIG bus handles flash ROM data (system diagnostics and console programs)

and system interrupts.

The cross-bar switch is controlled by the C-chip which synchronizes, along with the
clock, the D-c hips, th e CPUs, me m ory, and the P- chi p s. Figure 1- 10 sho ws the major
data paths through the system.

The C-chip contains:

• Buffers for requests for the P-chips (shared), and each CPU

• Request queues for each memory bank

• A CPU interface for probe and fill requests and issues

• A P-chip interfac e co ntroller and bridg e b etween PCI comman ds and addresses

and CPU PIO commands and addresses

• D-chip contr olle r s, o ne for the PAD bus and one fo r ever yth i ng el se

The D-chip contains:

• Queues to and from t he P-c hip , to an d from th e CPUs, and to and from memory

• Control from the C-chip

The P-chip contains:

• Upstream (away from the PCI) and downstream (toward the PCI) data queues

• Upstream and downstream address queues

• An upstream address state machin e fo r DMA and peer-to-peer reads and writes

• A scatter/gather table for direct mapped and scatter/gather DMA memory access

System Overview 1-19

1.8.2 I/O Subsystem

s

The I/O subsystem consists of two 64-bit PCI buses. One has an embedded ISA
bridge, three PCI option slots, and a single ISA sl ot; the other bus has three PCI
option slots.

Figure 1-11 PCI Block Diagram

Crossbar

Switch

8 D Chips

P Chip

PCI 1

I/O ASIC

CAP Bus (24 bits)

P Chip

PCI 0

C Chip

PAD Bus (32 bits)

1 ISA

Slot

Cypress Chip

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PCI-0

3 64-bi t slots

(ISA Bridge,
IDE, KBRD,

MSE, USB)

ADAPTEC
Ultra SCSI

Controller

(2 ports)

1-20 AlphaServer DS20 Service Manual

COM1
COM2

Parallel
Port

Floppy

PCI- 1 B u

PCI-1

3 64-bi t slots

PK1494- 9 8

Table 1-1 PCI Slot Numbering

Slot PCI0 PCI1 ISA Shared

5 PCI to ISA bridge ISA device logically
6 Adaptec SCSI
7 PCI slot PCI slot
8 PCI slot PCI slot
9 PCI slot PCI slot ISA device physically

The logic for two PCI buses is on the system board.

• PCI0 is a 64-bit bus with three PCI slots, a Cypress chip, and an Adaptec SCSI

controller. The Cypress chip is the PCI to ISA bus bridge and controls the
following: the keyboard, mouse, IDE bus, real-time clock, and the USB bus. (The
IDE bus an d the USB bus ar e not used.) Conne cted to the ISA bus is an Adapte c
UltraSCSI controller with two ports (also not used).

• PCI1 is a 64-bit bus with three PCI slots.

The cable connector to the floppy is on the system board. Connectors for the mouse,
keyboard, and COM2 are on the bulkhead and are connected directly to the Cypress
chip. The connector for COM1 is also on the bulkhead, but its path is from the
Cypress chip to the RCM connector out to the server featur e module and back throu gh
the RCM co n nector and then to the b u lkhead. The p ath to the OCP is also carri ed
through the RCM connector to the server feature module and then on to the OCP.

System Overview 1-21

1.8.3 System Board Switchpacks

PK1410-99

fsb

coa

cob

mdb

sp0

sp1

sp2

pby

cn7

cn2

cn3

cn4

cn5

cn6

spr

flash_wr

There are two switchpacks on the syste m board. They control the wri ting of t he
flash ROM and the speed of the crossbar switch among other things.

Figure 1-12 Switchpack Location

Off On

1
2
3
4
5
6
7
8

SW2

Off On

D

Chip

D

Chip

P

ChipPChip

CPU 0

CPU 1

System Board

1-22 AlphaServer DS20 Service Manual

SW2
SW3

1
2
3
4
5
6
7
8

SW3

Figure 1-12 shows the location of the switchpacks and Table 1-2 and Table 1-3
describe what each switch controls.

Table 1-2 Switchpack 2

Switch Description

1 Fail safe bo ot. O ff (defa ult) = normal boot. On = boot the fail safe bo oter
2 Reserved. Must be off.
3 Reserved. Must be off.
4 Reserved. Must be off.
5
6
7

Switches 5, 6, and 7 create a field that defines the speed at which the cross
bar switch runs. Switches 5 and 6 are on and switch 7 is off.

8 AlphaBIOS Password bypass: Off (default) = Normal operation;

On = Bypass AlphaBIOS password

Table 1-3 Switchpack 3

Switch Description

1 Reserved. Must be off.
2 Reserved. Must be off.
3 Reserved. Must be off.
4 Reserved. Must be on.
5 Reserved. Must be off.
6 Reserved. Must be off.
7 Reserved. Must be off.
8 Flash write protect: Off (default) = Write enable the flash ROM

On = Write d isable the fl ash ROM

System Overview 1-23

1.9 Server Feature Module

K

The server feature module provides remote control operation of the system. A
four-switch switchpack enables or disables remote control features.

Figure 1-13 Server Feature Module

Power
Connector

RCM

Connector

5 Vaux

Power OK

System Fan

Connectors

Switchpack
Interlock

Connector
Sys Fan OK

CPU Fan O
Temp OK

OCP

Connector

1-24 AlphaServer DS20 Service Manual

PK1492-98

The system allows both local and remote control. The remote control firmware and a
set of switches that enable or disable remote control features reside on the server
feature module.

Table 1-4 Remote Control Switch Functions

Switch Condition Function

1 EN RCM

2 Reserved NA Reserved

On (default)
Off

Allows remote system control
Does not allow remote system control

3 RPD DIS On

Off (default)

4 SET DEF On

Off (default)

Disables remote power down
Enables remote power down

Resets the RCM microprocessor defaults
Allows use of conditions set by the user

The defau lt setting s allow comp lete remote control. The user wo uld have to change th e
switch settings to any other desired control.

See Appendix C for information on controlling the system remotely.
The server feature module connects to COM1 on the bulkhead so that its remote

console functions can be accessed. The RCM uses VAUX power provided by the
system power supplies.

The interlock circuit runs through the server feature module as does the path to the
OCP. See Section 1.1.

System Overview 1-25

1.9.1 Power Control Logic

K

The power control logic is on the server feature module.

Figure 1-14 Power Control Logic

Power
Connector

RCM

Connector

5 Vaux

Power OK

Switchpack
Interlock

Connector
Sys Fan OK

CPU Fan O
Temp OK

Connectors

Fa n

OCP

Connector

PK1492-98

1-26 AlphaServer DS20 Service Manual

The power control logic performs these functions:

• Monitors system temperature and powers down the system 30 seconds after it

detects that internal temperature of the system is above the value of the
environment variable over_temp. Default = 55

0

C.

• Monitors the system and CPU fans and powers down the system 30 seconds after

it detects a fan failur e .

• Provides some visual indication of faults throu gh LEDs.

• Provides I









2

C interface for fans, power supplies, and temp era tur e signals :
Power supply 0, 1: present
Power supply 0, 1: power OK
CPU fan 0, 1: OK
CPU 0, 1: present
Overtemp: Temp OK
System fan 0, 1: OK
Fan Kit OK

System Overview 1-27

1.10 Power Circuit and Cover Interlock

Power is distribute d throughout the system and mechanically can be broken by
the On/Off switch, the cover interlock, or remotely through the RCM.

Figure 1-15 Power Circuit Diagram

Power

Supply

Server Feature Module

Switch

pack

OCP

Connector

Cover

Interlock

Push button

ON/OFF

OCP

DC_ENABLE_L

PK1493-98

1-28 AlphaServer DS20 Service Manual

Figure 1-15 shows the distribution of the power enable circuit through the system.
Opens in the circui t, or the RCM s ig nal RCM_DC _EN_L, or a power sup ply dete cted
power fault causes interruption to the DC power applied to the system.

A failure anywhere in the circuit will result in the removal of DC power. A potential
failure is the relay used in the remote control logic to control the RCM_DC_EN_L
signal.

The cover interlock is located under the top cover between the system card cage and
the storage area. To override the interlock, place a suitable object in the interlock
switch that closes it.

System Overview 1-29

1.11 Power Supply

Two power supplies provide sy stem power.

Figure 1-16 Back of Power Supply and Location

Power
Supply 1

+5V/Return

+3.4V/Return

Current
share

Power
Supply 0

+5V/Return
+12V/Return

Misc.
Signal

PK1495-98

1-30 AlphaServer DS20 Service Manual

Description

A single 675 watt power supply provides power to the system. A second power
supply (optional) provides redundant power.

Power Supply Features

• 88–132 and 176–264 Vrms AC input

• 675 watts output. Output voltages are as follows:

Output Voltage Min. Voltage Max. Voltage Max. Current

+5.0 4.85 5.25 100
+3.3 3.18 3.48 100
+12 11.5 12.6 28
–12 –10.9 –13.2 2
+5 Vaux 4.9 5.4 1.5

• Remote sense on +5.0V and +3.3V

+5.0V is sensed on the system board.
+3.3V is sensed on the system board.

• Current share on +5.0V, +3.3V, and +12V.

• 3% regulation on +3.3V.

• Fault protection (latched). If a fault is detected by the power supply, it will shut

down. The power supply faults detected are:

Fan Failure (overtemp)
Overvoltage
Overcurrent
Power overload

• DC_ENABLE_L input signal starts the DC outputs.

• SHUTDOWN_H input signal shuts the power supply off in case of a system fan,

or CPU fan failure, or an overtemp condition detected by the power control logic.

• POK_H output signal indicates that the power supply is operating properly.

System Overview 1-31

1.12 Power Up/Down Sequence

System power can be controlled manually by the On/Off button on the OCP or
remotely through t he RCM. The power-up/do wn sequence flo w is shown belo w.

Figure 1-17 Power Up/Down Sequence Flowchart

Apply AC

Power

Vaux on

Off

On-Off
Button

Assert

SHUTDOWN

30 Second

Delay

On

Disa ble Out puts

Deass ert PO K

On-Off Button

RCM Enable OK

Interlock OK

DC_ENABLE_L

Powe r Supply

Yes

No

Fan/Temp

Assert

Star t s

Any

Faults

Assert

POK

OK

On

No

Yes

Off

On

On-Off Button

DC_ENABLE_L

PK1409-99

Off

1-32 AlphaServer DS20 Service Manual

When AC is applied to the system, Vaux (auxiliary voltage) is asserted and is sensed
on the server feature module. If the On-Off Button is On, and RCM OK and Interlock
OK are asserted, the OCP asserts DC_ENAB LE _L star ti ng the powe r supplie s. If
there is a hard fault on power-up, the power supplies shut down immediately;
otherwise, the power system powers up and remains up until the system is shut off or
the server feature module senses a fault. If a power fault is sensed, the signal
SHUTDOWN is asserted af ter a 30 secon d delay. Cycling the On-Off button can
restore the power. If the system powers up and shuts off in approximately 30 seconds,
the server feature module has sensed a fault and a fan (system or CPU) is likely
broken.

System Overview 1-33

1.13 TIG Bus

The Timing, Interrupt, a nd General bus (TIG) performs a number of functi ons;
it carries all system interrupts, timing signals and provides the path to the
diagnostic and console flash ROMs.

Figure 1-18 TIG Bus Block Diagram

CPU
Data

D Chips

Bus

CPU s

Flash
ROM

PAD
Bus

CAP

Bus

TIG Bus

C ChipP Chip

Config

Registers

and

switchpack

Interrupt
data lines

IRQs

3.

1-34 AlphaServer DS20 Service Manual

Figure 1-18 is a block diagram of the TIG bus implemented through the TIG chip.
Three system functions are carried out on this bus.

Flash ROM

The flash ROM containing the diagnostics, fail-safe loader, and console firmware sits
on the TIG bus. (This is different from the AS 1200 where the flash ROM sat on the

2

C bus.) Still a good deal of logic has to function for the diagnostics to run.

I

Configuration Registers

Registers on the bus include interrupts, module information, and clock information.

Interrupts

System interrupts are passed through the TIG bus to the C-chip. The bus connects
directly to PCI slots and to onboard devices.

System Overview 1-35

1.14 Maintenance Bus (I2C Bus)

PK1406-99

P-Chip 0

ISA Bridge

There are two I2C buses (referred to as the “I squared C bus”) in this system.

The internal maintena nce bus is used to monitor syste m conditions scanned by
the power control logic on the server feature module, log error state and track
system configuration information. There is a private I
and the C-chip used to provide memory configuration information to the consoles
and operating syste m s.

Figure 1-19 I2C Bus Block Diagram

Server Feature

Module

NVRAM

C-Chip

2

C bus between memory

CPU 0

System

Board

1

I C Bus

Registers

Thermom/
Thermostat

OCP

Controller

2

PCL

Memory

2

I C Bus

Controller

Banks

Private

2

I C Bus

up to 4

XBUS

System

1-36 AlphaServer DS20 Service Manual

Monitor

2

C bus monitors the state of system conditions scanned by the power control

The I
logic. There are two registers that the PC logic writes data to:

• One records the state of the fans and power supplies and is latched when there is a

fault.

2

• The other causes an interrupt on the I

C bus when a CPU or system fan fails, an
overtemperature condition exists, or power supplied to the system changes from
N + 1 to N or from N to N +1.

2

The interrupt received by the I

C bus controller and passed on to P-chip 0 alerts the
system of a power system event that may or may not cause a power shutdown. In the
event of imminent power loss the controller has 30 seconds to read the two registers
and store the information in the NVRAM on the server feature module. The SRM
console command show power reads these reg isters .

Fault Display

2

The OCP display is written through the I

C bus.

Error State

Error state is stored for power, fan, and overtemperature conditions on the I

2

C bus.

Configuration Tracking

Each CPU and each logical section of the system board (the PCI bridge, the PCI
backplane, the power control logic, the remote console manager), and the system
board itself has an EEPROM that contains information about the module that can be
written and read over the I

2

C bus. All EEPROMs contain the following information:

• Module type

• Module serial number

• Hardware revision for the logical block

• Firmware revision

System Overview 1-37

1.15 StorageWorks Drives

7

The system support s up to seven StorageW orks dri ves.

Figure 1-20 StorageWorks Drive Location

StorageWorks
Drives Shelf

1-38 AlphaServer DS20 Service Manual

PKW0514-9

The StorageWorks drives are to the right of the system cage. Up to seven drives fit
into the shelf. The system supports fast wide UltraSCSI disk drives. The RAID
controller is also supported. With an optional UltraSCSI Bus Splitter Kit, the
StorageWorks shelf can be split into two buses.

System Overview 1-39

Chapter 2

Troubleshooting

This chapter describes troubleshooting during power-up and booting. It also describes
the console test command and other service related console commands. A Compaq
Analyze example is also provided. The following topics are covered:

• Troubleshooting During Power-Up

• Control Panel Display and Troubleshooting

• Power-Up Display and Troubleshooting

• Running Diagnostics — Test Command

• Testing an Entire System

• Other Useful Console Commands

• Troubleshooting with LEDs

• Compaq Analyze

• Releasing Secure Mode

Troubleshooting 2-1

2.1 Troubleshooting During Power-Up

Power or other problems can occ ur before the syste m is up and running.

Power Problem List

The system will halt/power off for the following reasons:

1. A CPU fan failure

2. A system fan failure

3. An overtemperature condition

4. Power supply failure if the redundant power option is not present

5. Circuit beaker(s) tripped

6. AC problem

7. Interloc k sw itch activation or failure

8. Environmental electrical failure or unrecoverable system fault with auto_action ev

= hal t or b oot

9. Cable failure

Indication of failure

• LEDs on the server feature module indicate fan, overtemperature, and power

problem conditions.

• Circuit breaker(s) tripped at the AC service panel.

• There is no obvious indication for failures 7 – 9 from the power system.

Beep Codes

Number Definition

1, 2, 3 beeps The firmware in flash ROM is corrupt.
4 beeps T he header in the ROM is not valid.
6 beeps A checksum error occurred after the ROM image was copied into

memory.

2-2 AlphaServer DS20 Service Manual

If the system does not power up

• Are the power cords plugged in?

• Is the power supply functioning? (The power supply will shut down if it detects

any faults. See Section 1.11.)

• Are the cover and side panels closed and the interlock engaged?

If the system comes up and approximately 30 seconds later goes down,
possible failures are:

• CPU fan failure

• System fan failure

• Overtemperature condit io n

If you hear a series of beeps (1, followed by 2, followed by 3)

These beeps indicate that the firmware in flash ROM is corrupt. The machine hangs
and the floppy light goes on.

Action:

1. On a working machine, insert the Alph a Syste m s Firmwa re Update Ve rsion V5.4

(minimum rev.) CD in the CD-ROM drive and copy the file PC264SRM.ROM
found in the DS20 subdirectory onto a floppy renaming the file to
DP264SRM.ROM.

2. Insert the floppy you just made into the floppy drive on the broken system.

3. Using the On/Off button, turn the machine off and then back on. The SRM

console will load from the floppy.

4. Place the Alpha Systems Firmware Update CD in the CD-ROM drive.

5. Run LFU and update the firmware.
Refer to Appendix C for instructions on updating firmware.

If you hear four beeps

The header in the ROM is not valid, and the system will not boot. Replace the system
board.

If you hear six beeps

Six beeps indicate a checksum error occurred after the ROM image was copied into
memory. Either memory is misconfigured or a memory DIMM needs to be reseated.

Troubleshooting 2-3

2.2 Control Panel Display and Troubleshooting

The control panel display indicates the likely device when testing fails.

Figure 2-1 Control Panel and LCD Display

AlphaServer DS20

PK1408

• When the On/Off button LED is on, power is applied and the system is running.

When it is off, the system is not running, but power may or may not be present. If
the power supplies are receiving AC power, Vaux is present on the server feature
module regardless of the condition of the On/Off switch.

• When the Halt button LED is lit and the On/Off button LED is on, the system

should be running either the SRM console or Windows NT.

2-4 AlphaServer DS20 Service Manual

Table 2-1 Control Panel Display

Content of Display Progress Indicated in Power-Up Flow

Compaq CPU functioning, path to the OCP operating. Hardware

involved – CPU, C-chip, P-chip 0, PCI to ISA bridge,
ISA to XBUS bridge, OCP contro ll e r.

Compaq * B-cache initialized and both B-cach e and memory is

being tested. Additional hardware involved: Backup
cache on the CPU module, D-chips, memory DIMMs.

Compaq Firmware Firmware loading. Additional hardware involved – TIG

bus.

Compaq Error 06

Probe I/O Subsystem SRM console probing the system. Additional hardware

AlphaServer DS20 Either the SRM console or AlphaBIOS are up and

Memory error. No memory was found, or memory is
bad, or misconfigured, or needs re-seating.

involved – P-chip 1, all devices on both PCIs.

running.

Troubleshooting 2-5

2.3 Power-Up Display and Troubleshooting

If the power-up display appears, the following hardware is at least partially
functioning: at least one CPU, the C-chip, some D-chips, the P-chips, the TIG
bus, the ISA bridge, and the I
serial terminal (if the console environment variable is set to serial); the last
several lines print to either a serial terminal or a graphics monitor. Power-up
status also is seen on the control panel di spl ay.

Example 2–1 Power-Up Display

512 Meg of system memory ➊
probing hose 1, PCI ➋

bus 0, slot 7 -- pka -- QLogic ISP1040
bus 0, slot 8 -- ewa -- DECchip 21140-AA
probing hose 0, PCI
probing PCI-to-ISA bridge, bus 1
bus 0, slot 5, function 1 -- dqa -- Cypress 82C693 IDE
bus 0, slot 5, function 2 -- dqb -- Cypress 82C693 IDE
bus 0, slot 6, function 0 -- pkb -- Adaptec AIC-7895
bus 0, slot 6, function 1 -- pkc -- Adaptec AIC-7895
bus 0, slot 7 -- vga -- DEC PowerStorm
bus 0, slot 8 -- ewa -- DECchip 21040-AA

Testing the System
Testing the Disks (read only)
Testing the Network
System Temperature is 22 degrees C

2

C bus. The entire power-up display prints to a

➌

Compaq AlphaServer DS20 Console V5.4, Aug 26 1998 16:07:57 ➍

P00>>>

2-6 AlphaServer DS20 Service Manual

By the time the power-up display is completed,

1. the CPUs have run their self-te sts,

2. the SROM has completed its preliminary tests and loaded the SRM console from

flash ROM on the TIG bus into memory,

3. the SROM has passed control to the SRM console,

4. the SRM has polled the system , r un its sy stem dia g nost ic s, a nd has sent t he

display characters.

If the system’s operating system is NT, you will not see any of the power-up display
before the line that says “Testing the System.”

➊ Memory size is determined by the C-chip.
➋ The PCI bridges and attendant buses (indicated as IODn by the cons o le) are

probed and the devices are reported. I/O adapters are configured. At a
minimum, the devices are responding to probes by the console program.

➌ The system, disks, and network are tested by the console.
➍ The SRM console banner and prompt are printed. (The SRM prompt is shown in

this manual as P00>>>. It can, however, be P01>>>. The number indicates the
primary processor.) If the auto_action environment variable is set to boot or
restart an d the os_type environment variable is set to unix or openvms, the
Compaq Tru64 UNIX or OpenVMS operating system boots.

If the system is running the Windows NT operating system (the os_type
environment variable is set to nt), the SRM console loads and starts the
AlphaBIOS console.

Refer to Chapters 4 and 5 of the AlphaServer DS20 User’s Guide for

information about the SRM console and AlphaBIOS.

Troubleshooting 2-7

2.4 Running Diagnostics — Test Command

The test command runs diagnostics on the entire system, CPU devices, memory
devices, and the PCI I/O subsystem. The test command runs only from the SRM
console. Ctrl/C stops the test . T he console canno t be sec ure.

Example 2–2 Test Command Syntax

P00>>> help test
NAME
test
FUNCTION
Test the system.
SYNOPSIS
test [-lb] [-t <time>]

COMMAND ARGUMENT(S):
P00>>>

P00>>>
P00>>>

SYNOPSIS
test ([-lb] [-t <time>]
The entire system is tested by default.

NOTE: If you are running the Microsoft Windows NT operating system, switch from
AlphaBIOS to the SRM console in order to enter the test command. From th e
AlphaBIOS console, press in the Halt button (the LED will light) and reset the system,
or select Tru64 UNIX (SRM) or OpenVMS (SRM) from the Advanced CMOS Setup
screen and reset the system.

test [-lb] [-t time]

-lb Loop back test enable. Loop back connectors are needed on COM1,

COM2, and the parallel port.

-t time Specifies the run time in seconds. The default for system test is 600

seconds (10 minutes).

2-8 AlphaServer DS20 Service Manual

2.5 Testing an Entire System

A test command runs all exercisers for subsystems and devices on the system.
I/O devices tested are suppor ted bo o t devices. The test runs f or 2 minute s.

Example 2–3 Sample Test Command

P00>>> test

System test, runtime 120 seconds

Type ^C if you wish to abort testing once it has started

Default zone extended at the expense of memzone.
Use INIT before booting

Testing Ethernet device(s)
Testing VGA
Testing Memory

Testing SCSI disks (read-only)
Testing other SCSI devices (read-only)..

Testing floppy drive (dva0, read-only)
No diskette present, skipping floppy test

ID Program Device Pass Hard/Soft Bytes Wrtn Bytes Rd

-------- ------------ ---------- ----- -------- ---------- ---------­00001c12 memtest memory 1 0 0 352321536 352321536
00001c17 memtest memory 1 0 0 352321536 352321536
00001c35 memtest memory 1 0 0 352321536 352321536
00001c80 exer_kid dkb100.1.0.9 0 0 0 0 4915200
00001c83 exer_kid dkb200.2.0.9 0 0 0 0 4898816
00001c85 exer_kid dkb300.3.0.9 0 0 0 0 4898816
00001cc7 exer_kid dke0.0.0.200 0 0 0 0 6144000
00001cc8 exer_kid dke200.2.0.2 0 0 0 0 6144000
00001cc9 exer_kid dke400.4.0.2 0 0 0 0 6127616
00001cf7 exer_kid dkf100.1.0.2 0 0 0 0 8830976
00001cfa exer_kid dkf300.3.0.2 0 0 0 0 8814592

ID Program Device Pass Hard/Soft Bytes Wrtn Bytes Rd

-------- ------------ ---------- ---- ---------- ---------- --------­00001c12 memtest memory 1 0 0 713031680 713031680
00001c17 memtest memory 1 0 0 721420288 721420288
00001c35 memtest memory 1 0 0 713031680 713031680
00001c80 exer_kid dkb100.1.0.9 0 0 0 0 12730368
00001c83 exer_kid dkb200.2.0.9 0 0 0 0 12713984
00001c85 exer_kid dkb300.3.0.9 0 0 0 0 12713984
00001cc7 exer_kid dke0.0.0.200 0 0 0 0 8749056
00001cc8 exer_kid dke200.2.0.2 0 0 0 0 8749056
00001cc9 exer_kid dke400.4.0.2 0 0 0 0 8749056
00001cf7 exer_kid dkf100.1.0.2 0 0 0 0 13533184
00001cfa exer_kid dkf300.3.0.2 0 0 0 0 13516800

Continued on next page

Troubleshooting 2-9

ID Program Device Pass Hard/Soft Bytes Wrtn Bytes Rd

-------- ------------ ---------- ----- -------- ---------- ---------­00001c12 memtest memory 2 0 0 1082130432 1082130432
00001c17 memtest memory 2 0 0 1082130432 1082130432
00001c35 memtest memory 2 0 0 1073741824 1073741824
00001c80 exer_kid dkb100.1.0.9 0 0 0 0 20086784
00001c83 exer_kid dkb200.2.0.9 0 0 0 0 20086784
00001c85 exer_kid dkb300.3.0.9 0 0 0 0 20086784
00001cc7 exer_kid dke0.0.0.200 0 0 0 0 16531456
00001cc8 exer_kid dke200.2.0.2 0 0 0 0 16515072
00001cc9 exer_kid dke400.4.0.2 0 0 0 0 16515072
00001cf7 exer_kid dkf100.1.0.2 0 0 0 0 23511040
00001cfa exer_kid dkf300.3.0.2 0 0 0 0 23494656

ID Program Device Pass Hard/Soft Bytes Wrtn Bytes Rd

-------- ------------ ---------- ----- -------- ---------- ---------­00001c12 memtest memory 2 0 0 1442840576 1442840576
00001c17 memtest memory 2 0 0 1442840576 1442840576
00001c35 memtest memory 2 0 0 1442840576 1442840576
00001c80 exer_kid dkb100.1.0.9 0 0 0 0 28852224
00001c83 exer_kid dkb200.2.0.9 0 0 0 0 28852224
00001c85 exer_kid dkb300.3.0.9 0 0 0 0 28852224
00001cc7 exer_kid dke0.0.0.200 0 0 0 0 19513344
00001cc8 exer_kid dke200.2.0.2 0 0 0 0 19513344
00001cc9 exer_kid dke400.4.0.2 0 0 0 0 19513344
00001cf7 exer_kid dkf100.1.0.2 0 0 0 0 29917184
00001cfa exer_kid dkf300.3.0.2 0 0 0 0 29900800

ID Program Device Pass Hard/Soft Bytes Wrtn Bytes Rd

-------- ------------ ---------- ----- -------- ---------- ---------­00001c12 memtest memory 2 0 0 1803550720 1803550720
00001c17 memtest memory 2 0 0 1811939328 1811939328
00001c35 memtest memory 2 0 0 1803550720 1803550720
00001c80 exer_kid dkb100.1.0.9 0 0 0 0 36241408
00001c83 exer_kid dkb200.2.0.9 0 0 0 0 36241408
00001c85 exer_kid dkb300.3.0.9 0 0 0 0 36241408
00001cc7 exer_kid dke0.0.0.200 0 0 0 0 26968064
00001cc8 exer_kid dke200.2.0.2 0 0 0 0 26968064
00001cc9 exer_kid dke400.4.0.2 0 0 0 0 26968064
00001cf7 exer_kid dkf100.1.0.2 0 0 0 0 38158336
00001cfa exer_kid dkf300.3.0.2 0 0 0 0 38158336
^C
P00>>>

2-10 AlphaServer DS20 Service Manual

2.6 Other Useful Console Commands

Several console comma nds can be use d to diagnose the syste m.

The show power command identifies power, temperature, and fan faults.

Example 2–4 Show Power

P00>>> show power

Status
Power Supply 0 good
Power Supply 1/Fan Tray good
System Fans good
CPU Fans good
Temperature good

Current ambient temperature is 27 degrees C
System shutdown temperature is set to 55 degrees C

1 Environmental events are logged in nvram
Do you want to view the events? (Y/<N>) y

Total Environmental Events: 1 (1 logged)

1 NOV 11 18:00 System Fan 0 Failure, Power Supply 0,1 Failure

Do you want to clear all events from nvram? (Y/<N>) n
P00>>>

The show memory command shows memory DIMMs and their starting addresses.

Example 2–5 Show Memory

P00>>> show memory

Array # Size Base Addr

------- ---------- --------­ 0 512 MB 000000000
1 512 MB 020000000
2 256 MB 040000000
3 128 MB 050000000

Total Bad Pages = 0

Total Good Memory = 1408 MBytes

P00>>>

Troubleshooting 2-11

2.7 Troubleshooting with LEDs

K

During power-up, reset, initialization, or testing, diagnostics are run on CPUs,
memories, P-chi ps, and the PCI backplane and its embedded options. Although
system LEDs are not visible when the side pa nel s are on, they ca n be viewed when
the card cage side of the system is exposed and the top cover is on. There are
LEDs on the CPU and server feature modules.

Figure 2-2 CPU and Server Feature Module LEDs

CPU Self-test

CPU DC OK

SROM Clk

2V OK
5V OK

CPU

Module

Server

Feature

Module

5 Vaux

Power OK

2-12 AlphaServer DS20 Service Manual

Sys Fan OK
CPU Fan O

Temp OK

PK1407-99

To see LEDs, the card cage side of the system must be exposed; the system top should
be on, and the system must be on.

CPU LEDs

The CPU LEDs are on the under side of the module. Figure 2-2 shows the location of
the LEDs when looking up at the module. Normally all CPU LEDs are on except the
SROM Clock LED.

Replace the CPU if the 5V OK LED is on and any of the following LEDs are off: CPU
DC OK, or 2V OK.

If the 5V OK LED is off, power is not getting to the CPU. The problem could be the
power harness, the power translation board, the power supply, or the CPU.

If the CPU self-test LED is off, the built-in self-test on the CPU chip did not complete
for some reason.

Server Feature Module LEDs

All the LEDs on this module are normally on.
If the 5 Vaux Power OK LED is off, power is not getting to the module and the

problem could be the power harness, the power translation board, the power supply, or
the server feature module.

If the Sys Fan OK LED is off, a system fan is broken. Use the show power command
to determine which.

If the CPU Fan OK LED is off, a CPU fan is broken. Use the show power command
to determine which.

If the Temp OK LED is off, the temperature in the cabinet is above the temperature
thresho ld. Several th ings can cause this con dition: b locked airf low, temp er ature in the
room where the system is located is too high, the system card cage is open and air is
not channeled properly over the system. Fix any of these conditions, if possible. The
overtemperature threshold is programmable and is controlled by the environment
variable over_temp. Its default is 55 degrees C. After the system has cooled down
and can be powered up, you can change the threshold. If you do this and the
temperature inside the system gets too hot, it is likely that system errors will occur and
the system may crash. If the system gets too hot, hardware can be damaged.

Troubleshooting 2-13

2.8 Compaq Analyze

Compaq Analyze is the error analysis tool used to analyze errors. An example of
its output is shown here. For information on installing, running, and learning
about Compaq Analyze, go t o http: // www.e v nr ud.c x o. dec .c o m/desta/kits. htm.

2.8.1 Compaq Analyze Graphics Interface (GUI)

Compaq Analyze automatically runs on each of the supported operating systems
on the DS20 system.

Figure 2-3 Compaq Analyze Graphics Interface

2-14 AlphaServer DS20 Service Manual

PK1411-99

Figure 2-3 shows an example of what you can expect to see on a system’s console,
assuming it is a graphics terminal and Compaq Analyze is installed and running in the
backround. When an error is detected, it is reported to the console with a series of
problem found statements. In this case, “an uncorrectable system fan 0 error
detected,” was logged a couple of times in the event log with a time stamp of Friday
March 12, 1999.

To get a full analysis of the error, double click on the Problem Found: hot spot on the
active screen and a full report of the error is displayed.

Troubleshooting 2-15

2.8.2 Description of the Error

After “double clicking” the Problem Found: hot spot on the Compaq Analyze
screen a full description of the error is displayed and a FRU and its location is
called out. Example 2–6 shows a Compaq Analyze error report.

Example 2–6 Compaq Analyze Error Report

Problem Found: An uncorrect able sy stem fan 0 error det ected.

Managed Entity:

System Entity: enugu Error Environment:
Record Number :
Event ID_Count:2Ev ent ID_P refi x:15 008
Event Time:

Time of Error : Thu, 11 Mar 1999 12:43:58 –0500

Brief Description:

An uncorrectable system fan 0 error detected.

Callout ID:

0020050000072E05

Severity:

2

Reporting Node:

enugu

Full Description:

An uncorrectable system fan 0 error has been diagnosed. This System
error requires replacement service to be administered to Fan 0 Field
Replaceable Unit (FRU). This FRU is physically located in the
compartment to the right of the system card cage and is System Fan 0
– Upper Fan.

FRU List:

Probability: High
Manufacturer: Comp aq
Device Type: Power, Cooling, and Temperature
Physical Location: Slot System Fan 0 -­FRU Part Number: System fan 0 pn from config tree
FRU Serial Number: Fru SN from config tree
FRU Firmware Rev: NA

2-16 AlphaServer DS20 Service Manual

Evidence:

Entry Errlog: SMM_1838 SysType _34 OS_T ype_ 1 Entry_ Type _682
Entry_Type_Ana Mchk_Error_Cod
Event_Header_Common_Fields_V2_0
Event_Leader: xFFF FFFF E
Header_Length: 176
Event_Length: 312
Header_Rev_Maj or: 2
Header_Rev_Min or: 0
OS_Type: 1 ! 1 = UNIX, 2 = OVMS, 3 = NT
Hardware_Arch: 4
CEH_Vendor_ID: 3564
Hdwr_Sys_Type: 34
Logging_CPU: 0
CPUs_In_Active_Set: 2
Major_Class: 115
Minor_Class: 2
DSR_Msg_Num: 1838 !
CEH_Device: 35
Chip_Type: 8 ! 8 = EV6
CEH_Device_ID_0: x0000FFFF
CEH_Device_ID_1: x00000000
CEH_Device_ID_2: x00000000
Unique_ID_Count: 2
Unique_ID_Pref ix: 1500 8
Num_Strings: 2
Event_Header_UNIX_WNT_Specific_Fields_V2_0
Priority: 3
DID_Fmt: x00
Subid_Errcode: xFFFFFFFF
Subid_Num: 0
TLV_Processing_Support
TLV_Time_as_Local: Thu, 11 Mar 1999 12:43:58 -0500
TLV_Computer_Name: enugu
SMM_Decode_Support
System_Marketing_Model: 1838 !
System_Type: 34
Chip_Type: 8
Member_ID: 6
Chip_Speed: 500
Number_of_CPUs: 1
Entry_Type_Support
Entry_Type: 682 ! Machine Check type 682 (environment error)

Compaq AlphaServer

Compaq AlphaServer

DS20

DS20

Continued on next page

Troubleshooting 2-17

Systype34_Env_Regs_V1
Frame_Flags: x00000000
Mchk_Error_Code: x00000206
Frame_Rev: 1
SW_Sum_Flags: x000 0000 0000 0000 0
Cchip_DIR: x0001000000000000
Environ_QW_1: x000 0000 0000 0000 9
Environ_QW_2: x000 0000 0000 0004 F
Environ_QW_3: x000 0000 0000 0000 0
Environ_QW_4: x000 0000 0000 0000 0
Environ_QW_5: x000 0000 0000 0000 0
Environ_QW_6: x000 0000 0000 0000 0
Environ_QW_7: x000 0000 0000 0000 0
Environ_QW_8: x000 0000 0000 0000 0
Environ_QW_9: x000 0000 0000 0000 0
Subpacket_Supp ort
Subpacket_Head er_S uppo rt
Trailer_Frame_ Supp ort
Compaq Analyze Problem Report

2-18 AlphaServer DS20 Service Manual

Of particular interest in the error report is the Full Description of the error. If
Compaq Analyze is able to determine what failed on the machine, it gives a full
description of the failing FRU and its location. In this case the upper system fan is
identified as the failing part and its location is given.

Evidence provided depends upon the type of error detected. The types of errors
detected are given in Table 2-2. The evidence section of the Compaq Analyze report
provides information that lead the tool to identify the failing FRU and its location. For
more information, see the Regatta Platform Fault Management Specification.

Table 2-2 Types of Errors

Error Event Description

MCHK 670 Processor Machine checks. These are synchronous errors that

inform precisely what happened at the time the error occurred.
They are detected inside the CPU chip and are fatal errors.

MCHK 660 System machine checks. These are asynchronous errors that are

recorded after the error has occurred. Data on exactly what was
going on in the machine at the time of the error may not be

known. They are fatal errors.
MCHK 630 Processor correctable errors.
MCHK 620 System correctable errors.
MCHK 682 - 685 System environment failures that require repair (power supply

failure, system fan failure, overtemperature condition).
MCHK 687 Redundant power supply failure.

Troubleshooting 2-19

2.9 Releasing Secure Mode

The console cannot be secure for most SRM console commands to run. If the
console is not secure, user mode console commands can be entered. See the
system manager if the syste m is secure and you do not know the passwor d.

Example 2–7 Releasing/Reestablishing Secure Mode

P00>>> login
Please enter password: xxxx
P00>>>

[User mode SRM console commands are now available.]

P00>>> set secure

The console command login clears secure.
If the password has been forgotten and the system is in secure mode, enter the login

command:

P00>>> login
please enter password:

At this prompt, press the Halt button and then press the Return key.
The password is now cleared and the console is in user mode. A new password must

be set to put the console into secure mode again.
For a full discussion of securing the console, see your system User’s Guide.

2-20 AlphaServer DS20 Service Manual

Chapter 3

Error Registers

This chapter describes the following registers used to hold error information:

• Ibox Status Register - I_STAT

• Memory Management Status Register – MM_STAT

• Dcache Status Register – DC_STAT

• Cbox Read Register

• Miscellaneous Register (MISC)

• Device Interrupt Request Register (DIRn, n=0,1)

• Pchip Error Register (PERROR)

• Failure Register

• Function Register

Error Registers 3-1

3.1 Ibox Status Register - I_STAT

3

The Ibox Status Register (I_STAT) is a read/write-1-to-clear register that
contains Ibox status information. The register is read only by PAL code and is
an element in the CPU or System Uncorrectable Machine Check Error Logout
frame.

3031 29 28

TPE
DPE

61

PK1414-99

Table 3-1 Ibox Status Register

Name Bits Type Description

Reserved <63:31> RO Reserved for Compaq.
DPE

<30> W1C

TPE <29> W1C

Icache data parity error
When set, indicates that the Icache

encountered a data parity error on instruction
fetch.

Icache tag parity error
When set, indicates that the Icache

encountered a tag parity error on instruction
fetch.

0

2

Reserved <28:0> RO Reserved for Compaq.

3-2 AlphaServer DS20 Service Manual

3.2 Memory Management Status Register –

3

MM_STAT

The Memory Management Status Register (MM_STAT) is a read-only register.
When a Dstream TB miss or fault occurs, information about the error is latched
in MM_STAT. This register is not updated when a LD_VPTE gets a DTB miss
instruction. The register is read only by PALcode and is an element in the CPU
or System Uncorrectable Machine Check Error Logout frame.

61

31

DC_TAG_PERR

OPCODES<5:0>

FOW

FOR
ACV

WR

2

1011 49321

0

PK1415-99

Error Registers 3-3

Table 3-2 Memory Management Status Register

Name Bits Type Description

Reserved <63:11> Re served for Compaq.

DC_TAG
_PERR

<10> RO This bit is set when a Dcache tag parity error occurs

during the initial tag probe of a load or store
instruction. The error created a synchronous fau lt
to the D_FAULT PALcode entr y poi nt and is
correctable. The virtual address associated with the
error is available in the VA register.

OPCODE <9:4> RO Opcode of the instruction that caused the error.

HW_LD is displayed as 3 and HW_ST is displayed
as 7.

FOW < 3> RO Set when a fault-on-write error occurs during a

write transaction and PTE[FOW] was set.

FOR <2> RO Set when a fault-on-read error occurs during a read

transaction and PTE[FOR] was set.

ACV <1> RO Set when an access violation occurs during a

transaction. Access violations include a bad virtual
address.

WR < 0> RO Set when an error occurs during a write transaction.

3-4 AlphaServer DS20 Service Manual

3.3 Dcache Status Register – DC_STAT

3

1

The Dcache Status Register (DC_STAT) is a read-write register. If a Dcache tag
parity error or data ECC error occurs, information about the error is latched in
this register. The register is read only by PALcode and is an element in the CPU
or System Uncorrectable Machine Check Error Logout frame.

61

31

ECC_ERR_LD
ECC_ERR_ST

TPERR_P1

TPERR_P0

SEO

432

PK1416-99

2

0

Error Registers 3-5

Table 3-3 Dcache Status Register

Name Bits Type Description

Reserved < 63:5> Reserved for Compaq.

SEO < 4> W1C Second error occured. When set, indicates that a

second Dcache store ECC error occurred within 6
cycles of the previous Dcache store ECC error.

ECC_ERR
_LD

<3> W1C ECC error on load. When set, indicates that a

single-bit ECC error occurred while processing a
load from the Dcache or any fill.

ECC_ERR
_ST

<2> W1C ECC error on store. When set, indicates that an

ECC error occurred while processing a store.

TPERR_P1 <1> W1C Tag parity error — pipe 1. When set, indicates that

a Dcache tag probe from pipe 1 resulted in a tag
parity error. The error is uncorrectable and results
in a machin e check.

TPERR_P0 <0> W1C Tag parity error — pipe 0. When set, this bit

indicates that a Dcache tag probe from pipe 1
resulted in a tag parity error. The error is
uncorrectable an d r es u lts in a machine che ck.

3-6 AlphaServer DS20 Service Manual

3.4 Cbox Read Register

The Cbox Read Register is read 6 bits at a time. Table 3-4 shows the ordering
from LSB to MSB. The register is read only by PALcode and is an element in the
CPU or System Uncorrectable Machine Check Error Logout frame.

Table 3-4 Cbox Read Register

Name Description

C_SYNDROME_1
<7:0>

C_SYNDROME_0
<7:0>

C_STAT<4:0>

Syndrome for the upper QW in the OW of victim that was
scrubbed.

Syndrome for the lower QW in the OW of victim that was
scrubbed.

Bits Error status

00000 Either no error, or error on a speculative load, of a

Bcache victim read due to a Dcache/Bcache miss.
00001 BC_PERR (Bcache tag parity error)
00010 DC_PERR (duplicate tag parity error
00011 DSTREAM_MEM_ERR
00100 DSTREAM_BC_ERR
00101 DSTREAM_DC_ERR
0011X PROBE_BC_ERR
01000 Reserved
01001 Reserved
01010 Reserved
01011 ISTREAM_MEM_ERR
01100 ISTREAM_BC_ERR
01101 Reserved
1XXXX DOUBLE_BIT_ERROR

Error Registers 3-7

Table 3-4 Cbox Read Register (Continued)

Name Description

C_STAT<3:0>

C_ADDR
<6:42>

If C_STAT equals xxx_MEM_ERR or xxx_BC_ERR, then
C_STAT contains the status of the block as follows; otherwise, the
value of C_STAT is X.

Bit valus Status of block

7 - 4 Reserved

3 Parity
2 Valid
1 Dirty
0 Shared

Address of the last reported ECC or parity error. If C_STAT value
is DSTREAM_DC_ERR, only bits <6:19> are valid.

3-8 AlphaServer DS20 Service Manual

3.5 Miscellaneous Register (MISC)

This register is designed so that only writes of 1 affect it. When a 1 is written to
any bit in the register, the programmer does not need to be concerned with read­modify-write or the status of any other bits in the register. Once NXM is set, the
NXS field is locked. It is unlocked when software clears the NXM field. The
ABW (arbitration won) field is locked if either ABW bit is set, so the first CPU to
write it locks out the other CPU. Writing a 1 to ACL (arbitration clear) clears
both ABW bits and both ABT (arbitration try) bits and unlocks the ABW field.

Address 801 A000 0040

Access RW

63

44 43 40 39

reserved

DEVSUP

REV

31 43

29 28 27 2524 23 20 19 16 15 12 11 8 7 2 1

000

00

NXM
NXS

ACL
ABT

ABW

IPREQ

IPINTR

ITINTR

CPUID

32

0

PK1417-99

Error Registers 3-9

Table 3-5 Miscellaneous Register

Initial

Name Bits Type

RES <63:44> MBZ, RAZ 0 Reserved.
DEVSUP <43:40> WO 0
REV <39:32> RO 1 Latest revision of the Cchip:

NXS <31:29> RO 0 NXM source – Device that

NXM <28> R, W1C 0 Nonexistent memory address

RES <27:25> MBZ, RAZ 0 Reserved.
ACL <24> WO 0 Arbitration clear – writing a 1

ABT <23:20> R, W1S 0 Arbitration try – writing a 1 to

State Description

1 = Tsunami

caused the NXM.
Unpredictable if NXM not set.
0 = CPU0, 1 = CPU1.

detected. Sets DRIR<63> and
locks the NXS field until it is
cleared.

to this bit clears the ABT and
ABW fields.

these bits sets them.

ABW <19:16> R, W1S 0 Arbitration won – writing a 1

IPREQ <15:12> WO 0 Inter proc essor int errup t

IPINTR <11:8> R, W1C 0 Interprocessor interrupt

3-10 AlphaServer DS20 Service Manual

to these bits sets them unless
one is already set, in which
case the write is ignored.

request – write a 1 to the bit
corresponding to the CPU you
want to interrupt. Writing a 1
here sets the corresponding bit
in the IPINTR.

pending – one bit per CPU.
Pin irq<3> is asse r ted to the
CPU corresponding to a 1 in
this field.

Table 3-5 Miscellaneous Register (Continued)

Initial

Name Bits Type

ITINTR <7:4> R, W1C 0 Interval timer interrupt

RES <3:2> MBZ, RAZ 0 Re served.

State Description

pending – one bit per CPU.
Pin irq<2> is asserted to the
CPU corresponding to a 1 in
this field.

CPUID <1:0> RO -

ID of the CPU performing the
read.

Error Registers 3-11

3.6 Device Interrupt Request Register (DIRn, n=0,1)

These registers indi cate which interrupts are pending to the CP Us and indicate
the presence of an I/O error condition.

Address 801 A000 0280 CPU0

801 A000 02C0CPU1

Access RO

58 5756 5563

00

IRQ1 PCI interrupts pending

Reserved
ERR

31

IRQ1 PCI interrupts pending

Table 3-6 Device Interrupt Request Register

Initial

Name Bits Type

ERR <63:62> RO 0

RES <61:56> RO 0 Reserved

State Description

IRQ0 error interrupts
<63> Cchip detected MISC <NXM>
<62> Pchip0 error
<62> Pchip1 error

32

0

PK1418-99

NXS <55:0> RO 0 IRQ1 PCI interrupts pending to the CPU

3-12 AlphaServer DS20 Service Manual

3.7 Pchip Error Register (PERROR)

If any bits <11:0> are set, this register is frozen. Only bit <0> can be set after
that. All other values are held until all bits <11:0> are clear. When an error
occurs and one of the <11:0> bits set, the associated information is captured in bit
<63:16>. After the information is captured, the INV bit is cleared, but the
informatio n is not vali d and should not be used if INV is set.

Address 801 8000 03C0 P0 ERROR

803 8000 03C0 P1 ERROR

Access RW

525150

55

63

56

44 43 40 39

32

ADDR

INV
CMD
SYN

31 43

16 15 12 11 8910 7 5621

ADDR

RES

CRE

UECC

RES

NDS

RDPE

TA

APE

SGE

DCRTO

PERR
SERR

LOST

0

PK1419-99

Error Registers 3-13

Table 3-7 Pchip Error Register

Initial

Name Bits Type

SYN <63: 56> RO 0 ECC syndrome of error if CRE or

State Description

UECC.

CMD <55:52> RO 0

INV <51>

RO Rev1
RAZ Rv0

ADDR <50:16> RO 0

PCI command when error occurred if not
CRE or UECC.
If CRE or UECC, then:

Value Command

0000 DMA read
0001 DMA read-modify-write
0011 SGTE read
Others Reserved

0

Info Not Valid – meaningful when one
of bits <11:0> is set. Indicates the
validity of SYN, C MD, and ADDR bit s.
Valid = 0, Invalid = 1.

If CRE or UECC, then ADDR<50:19> =
system address <34:3> of erroneous
quadword and ADDR<1 8:1 6> = 0.
If not CRE and not UECC, then
ADDR<50:48> = 0;
ADDR<47:18> = starting PCI address
<31:2> of transaction when error was
detected;
ADDR<17:16> = 00 → not a DAC
operation;
ADDR<17:16> = 01 → via DAC SG
Window 3;

ADDR<17> = 1 → via Monster Window

RES <15:12> MBZ, RAZ 0 Reserved
CRE <11> R, W1C 0 Correctable ECC error.
UECC <10> R, W1C 0 Uncorrectable ECC error.
RES <9> MBZ, RAZ 0 Reserved.
NDS <8> R, W1C 0 No b_devsel_l as PCI master.

3-14 AlphaServer DS20 Service Manual

Table 3-7 Pchip Error Register (Continued)

Initial

Name Bits Type

RDPE <7> R,W1C 0 PCI read data parity error as PCI master.
TA <6> R, W1C 0 Target abort as PCI master.

State Description

APE <5> R, W1C 0

Address parity error detected as potential PCI

target.
SGE <4> R, W1C 0 Scatter-gather had invalid page table entry.
DCRTO <3> R, W1C 0

Delayed completion retry timeout as PCI

target.
PERR <2> R, W1C 0 b_perr_l sa mpled asse rte d.
SERR <1> R, W1C 0 b_serr_l sampled asserted.
LOST <0> R, W1C 0

Lost an error because it was detected after

this register was frozen, or while in the

process of clearing this register.

Error Registers 3-15

3.8 Failure Register

L

This register, on the I2C bus, is locked when there is a power supply or fan
failure. Together with the Function Register, fan and power supply failures are
identifie d and reported to the operating system thus notifying it that the system
will shut down in 30 seconds. The results of readi ng thi s regi ster are displa yed by
the SRM show power console command.

I2C Bus Address 0111000

Access Read Only

12345670

11 11

Reserved
C/SFAN0_

Reserved

Reserved
PS1_PRESENT_L/FA N TRA Y
C/SFAN1_L
Reserved
PS0_PRESENT_L

3-16 AlphaServer DS20 Service Manual

PK1420-99

Table 3-8 Failure Register

Initial

Name Bits Type

PS0_PRESENT_L <7> RO X If the bit is clear, power supply 0 is

Reserved <6> RO 1 Reserved
C/SFAN1_L <5> RO X W hen set , indic at e s that either the

State Description

present.

system fan 1 or the fan on the
heatsink on CPU1 failed. Which
failed is determined by the state of
SYSFAN_OK and CPUFANS_OK
in the Fun ction Regis ter.

PS1_PRESENT_L
/FAN TRAY

<4> RO X If the bit is clear, either power

supply 1 or the system fan tray is

present.
Reserved <3> RO 1 Reserved
Reserved <2> RO 1 Reserved
C/SFAN0_L <1> RO X W hen set , indic at e s that either the

system fan 0 or the fan on the

heatsink on CPU0 failed. Which

failed is determined by the state of

SYSFAN_OK and CPUFANS_OK

in the Fun ction Regis ter.
Reserved <0> RO 1 Reserved

Error Registers 3-17

3.9 Function Register

K

The Function Register generates an interrupt on the I2C bus if one of the critical
functions monitored (power, temperature, fan operation) goes beyond
predetermined limits. When such an interrupt is generated, the contents of bits
<0, 1, 2, and 5> in the Failure Register are frozen. The sy stem wil l shut down 30
seconds after the interrupt is posted. The results of reading this register are
displayed by the SRM show power console command.

I2C Bus Address 0111001

Access RO

12345670

0

0

TEMP_OK
SYSF AN_OK

Reserved

CPUFANS_O
FANTRAY_FAIL_H
PS0_OK_L
PS1_OK_L
Reserved

PK1421-99

3-18 AlphaServer DS20 Service Manual

Table 3-9 Function Register

Initial

Name Bits Type

Reserved <7> RO 0 Reserved
PS1_OK_L <6> RO X When set, indicates that power

PS0_OK_L <5> RO X When set, indicates that power

FANTRAY_FAIL_H <4> RO X When clear, indicates that the

CPUFANS_OK <3> RO X When set, indicat e s that the fan s on

Reserved <2> RO 0 Reserved
SYSFAN_OK <1> RO X When set, indicates that the sy stem

TEMP_OK <0> RO X When set, indicates that the

State Description

supply 1 is functioning properly.

supply 0 is functioning properly.

fantray, if present is functioning
properly.

CPU heatsinks are functioning
properly.

fans are functioning properly.

temperature inside the system
enclosure is below the temperature
limit.

Error Registers 3-19

Chapter 4

Removal and Replacement

This chapter describes removal and replacement procedures for field-replaceable units
(FRUs).

4.1 System Safety

Observe the safety guidelines in this section to prevent personal injury.

CAUTION: Wear an antistatic wrist strap whenever you work on a system.

WARNING: When the system is off and plugged into an AC outlet, auxiliary power is
still supplied to the system. To remove all power, unplug the power supply. Note
though that unplugging the system will turn off LEDs that could identify the problem.

When the system interlocks are disabled and the system is still powered on, voltages
are low in the system, but current is high. Observe the following guidelines to prevent
personal injury.

Remove any jewelry that may conduct electricity before working on the system.

1.
If you need to access the system card cage, power down the system and wait 2

2.
minutes to allow components in that area to cool.

Removal and Replacement 4-1

4.2 FRU List

0

Server Feature

Figure 4-1 shows of the FRU locations and Table 4-1 lists the part numbers of the
field-replaceable units.

Figure 4-1 Some of the FRU Locations

Memory

CPUs

Auxiliary Fan

or Optional

Power Supp ly

Memory
Power

Supply

I/O Options

CD-ROM

P

C

System Board

SCSI
Disk s

OCP and
Display

U

Floppy

System Fan

Module

System Fan 1

PK1497-87

4-2 AlphaServer DS20 Service Manual

Table 4-1 Field-Replaceable Unit Part Numbers

CPU Modules

54-24758-01 C01 500 MHz CPU, 4 Mbyte cache

Memory Modules

54-25066-BA 32 Mbyte DIMM
54-25053-BA 64 Mbyte DIMM
54-25941-KA 128 Mbyte DIMM
54-25941-BA 256 Mbyte DIMM

System Backplane, Display, and Support Hardware

54-25756-01 D02 System board
54-25580-01 Serve r feature module
RX23L-AC Floppy
RRD47-AC CD-ROM
54-23302-02 OCP assembly
70-31349-01 Speaker assembly

Fans

70-31351-01 & -02 Cooling fan 120x120
70-33195-02 Auxiliary cooling fan assembly

Power System Components

30-48043-01 Power supply (cables connect to the power transition

module)

54-25588-01 Power transition module

SCSI Hardware

54-23365-01 & -02 SCSI backplane
30-48985-01 Ult raSCSI bus extender

Removal and Replacement 4-3

Table 4-1 Field-Replaceable Unit Part Numbers (Continued)

Power Cords

BN26J-1K North America, Japan 12V, 75-inches long
BN19H-2E Australia, New Zealand, 2.5m long
BN19C-2E Cent ral Europe, 2.5m long
BN19A-2E UK, Ireland, 2.5m long
BN19E-2E Switzerland 2.5m long
BN19K-2E Denmark, 2.5m long
BN19Z-2E Italy, 2.5m long
BN19S-2E Egypt, India, South Africa, 2.5m long
BN18L-2E Israel, 2.5m long

Ultra SCSI Signal Cables From To

17-04890-01 68 pin connector

cable

17-04022-03

68 pin connector
cable

SCSI controller UltraSCSI bus

extender

UltraSCSI bus
extender

SCSI backplane

signal connector
17-04021-01 68 pin conn jumper SCSI backplane SCSI backplane
17-04795-01

68 pin connector
cable

External port, SCSI
backplane

Terminator

12-41768-03 68 pin terminator End or 17-04795-01

System Cables and Jumpers From To

17-04532-01 Current share cable Crrnt shr conn, PS0 Crrnt shr conn, PS1
17-03970-01

34 pin Floppy signal
cable

17-03971-06 OCP signal

Flop connector on
system board

OCP connector on

Floppy

OCP signal

server feature module

Twisted pair (y & g)

Twisted pair (red
and black)

RCM connector on
server feature module

OCP

Power connector on

OCP

Interlock switch

pigtail

4-4 AlphaServer DS20 Service Manual

Table 4-1 Field-Replaceable Unit Part Numbers (Continued)

System Cables and
Jumpers From To

70-31348-01 Interlock switch

and pigtail cable

Interlock
switch
assembly

17-04796-01 20 pin signal cable RCM con on

system board

17-04886-01 SCSI CD-ROM

signal cable

17-04735-01 24 pin power

SCSI
backplane

Power supply Power transition module

harness

70-33578-01 Power harness Power

transition

Power supply

Twisted pair (red and
black) OCP DC enable
power cable from OCP
connector

RCM connector on server
feature module

CD-ROM signal
connector

3 connectors on sys board,
connector on CPU(s)

server feature module
CD-ROM drive power
Floppy power
Optional drive above flop
Single UltraSCSI config
StorageWorks backplane
and power cable to Ultra­SCSI bus extender
Dual UltraSCSI config
two power cables to two
SCSI bus extenders

17-04700-01 Power cable to

UltraSCSI bus
extender(s) Y
cable(s)

Power harness UltraSCSI bus extender(s)

power and StorageWorks
backplane

Removal and Replacement 4-5

4.3 System Access

Three sheet metal covers, one on top and one on each side, when removed provide
access to the system card cage and the power/ SCSI sec tio ns o f the system.

Figure 4-2 Accessing the System

Top Cover

Release Latch

4-6 AlphaServer DS20 Service Manual

,3

Exposing the System

CAUTION: Be sure the system On/Off button is in the “off” position before removing
system covers.

1. Shut down the operating system.

2. Press the On/Off button to turn the system off.

3. Unlock and open the door that exposes the storage shelf.

4. Pull down the top cover latch shown in Figure 4-2 until it latches in the down
position.

5. Grasp the finger groove at the rear of the top cover and pull it straight back about
2 inches and then lift it off the cabinet.

6. Pull a side panel back a few inches, tilt the top away from the machine, and lift it
off. (Repeat for the other side.)

7. From the back, removing the right side cover exposes the system card cage;
removing the left side cover exposes the power supply and SCSI backplane.

Dressing the System

Reverse the steps in the exposure process.

Removal and Replacement 4-7

4.4 CPU Removal and Replacement

8

CAUTION: Make sure all CPU modules are the same variant.

Figure 4-3 Removing CPU Module

PK1477-9

WARNING: CPU modules and memory modules have parts that operate at high
temperatures. Wait 2 minutes after power is removed before touching any module.

4-8 AlphaServer DS20 Service Manual

Removal

1. Shut down the operating system and turn the system off.

2. Expose the card cage side of the system (see Section 4.3).

3. Detatch the power cable from the CPU.

4. Loosen the two captive screws holding the module to the card cage.

5. Pull the CPU module from the system.

Replacement

Reverse the steps in the Removal procedure.

Verification — DIGITAL UNIX and OpenVMS Systems

1. Bring the system up to the SRM console by pressing the Halt button, if necessary.

2. Issue the show cpu command to display the status of the new module.

Verification — Windows NT Systems

1. Start AlphaBIOS Setup, select Display System Configuration, and press En ter.

2. Using the arrow keys, select Systemboard Configuration to display the status of
the new module.

Removal and Replacement 4-9

4.5 Memory Module Removal and Replacement

IP00315A

CAUTION: Several different memory DIMMs work in these systems. Be sure you are

replacing the broken DIMM with the same variant.

Figure 4-4 Removing Memory

WARNING: CPU modules and memory DIMMs have parts that operate at high
temperatures. Wait 2 minutes after power is removed before touching any module.

4-10 AlphaServer DS20 Service Manual