SERVICE MANUAL

PC40-ll |

C= commodore

COMPUTERS

SERVICE MANUAL

PC40-III

MARCH, 1989 PN-314134-01

CBM INTER-COMPANY (NOT FOR RESALE)

Commodore Business Machines, Inc. 1200 Wilson Drive, West Chester, Pennsylvania 19380 U.S.A.

Commodore makes no expressed or implied war- ranties with regard to the information contained herein. The information is made available solely on

_ anas is basis, and the entire risk as to quality and

- accuracy is with the user. Commodore shall not be liable for any consequential or incidental damages in connection with the use of the information con- tained herein. The listing of any available replace- ment part herein does not constitute in any case a recommendation, warranty or guaranty as to quality or suitability of such replacement part. Reproduction or use without expressed permission, of editorial or pictorial content, in any matter is prohibited.

This manual contains copyrighted and proprietary information. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permis- sion of Commodore Electronics Limited.

PC40-IIT SERVICE MANUAL

TABLE OF CONTENTS

SECTION 1 — SPECIFICATIONS

SECTION 2 — THEORY OF OPERATIONS SECTION 3 — TROUBLESHOOTING GUIDE SECTION 4 — PARTS

SECTION 5 — IC PINOUTS, SCHEMATICS APPENDIX A — POWER SUPPLIES APPENDIX B — DISK DRIVES

APPENDIX C — KEYBOARD

APPENDIX D — OPTIONS

APPENDIX E — TECHNICAL UPDATES

PC40-III SERVICE MANUAL

SECTION 1 SPECIFICATIONS

DESCRIPTION

PC40-III SERVICE MANUAL

This specification describes the Functional Requirements for the PC40-III computer. This system consists of a processor, memory, control unit and keyboard. This system is compatible with the IBM AT series of computers. The monitor for the system is an independent unit and must be VGA compatible.

STANDARD FEATURES MICROPROCESSOR SPEEDS

MEMORY CAPACITY VIDEO OUTPUT VIDEO DISPLAY RAM PARALLEL OUTPUT SERIAL OUTPUT

80286

6, 8, 12 MHz user selectable

1 MByte on board

Video Graphics Array compatible Horizontal scan frequency 31.5 KHz 256 KByte

Centronics (IBM) Compatible

RS-232 IBM Compatible

MOUSE PORT Commodore 1352 mouse Hardware and Software Compatible with Microsoft Bus Mouse

AutoConfig BIOS

BATTERY BACKED UP CLOCK EXPANSION SLOTS 3 AT style slots

1 XT style slot

40 MByte hard disk (formatted)

(AT style drive with embedded controller)

1.2 MByte Floppy Disk (formatted)

DISK STORAGE

112 WATT POWER SUPPLY

OPTIONAL FEATURES Math Coprocessor 80287.

Disk and Tape storage

1 40 MByte hard disk drive inside the case.

1 5.25" 1.2 MByte floppy drive accessible from the front of the unit.

1 unused slot that can be used for a second floppy or a streaming tape unit. Either or both floppy drives may be 3.5” drives.

Expansion slots

The three full length expansion slots conform to the standard AT bus structure, therefore, all options that are available for the AT on the after sale market are available on this unit.

The one XT expansion slot is for short cards that do not require a full length slot.

VIDEO FEATURES ALPHANUMERIC MODES

MODE # COL X ROW CHAR MATRIX RESOLUTION COLORS STANDARD 0, 1 40 X 25 8 X 8 320 X 200 16 CGA (1)

9X 16 360 X 400 16 OF 256K VGA (2) 2, 3 80 X 25 8X8 640 X 200 16 CGA (1)

9X 16 720 X 400 16 OF 256K VGA (2) 7 80 X 25 9X 14 720 X 350 MONOCHROME MDA

9X 16 720 X 400 MONOCHROME VGA (2) 54 132 X 43 7X9 924 X 387 COLOR ENHANCED 55 132 X 25 7X 16 924 X 400 COLOR ENHANCED 56 132 X 43 7X9 924 X 387 MONOCHROME ENHANCED 57 132 X 25 7X 16 924 X 400 MONOCHROME ENHANCED

IBM, AT and XT are registered trademarks of International Business Machine. AutoConfig is a registered trademark of Commodore Business Machine.

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GRAPHICS MODES:

MODE # RESOLUTION 4,5 320 X 200 6 640 X 200 D 320 X 200 E 640 X 200 F 640 X 350 10 640 X 350 11 640 X 480 12 640 X 480 13 320 X 200 NOTES

COLORS 4

4 OF 256K

2

2 OF 256K

16 OF 256K

16 OF 256K MONOCHROME 16 OF 256K

2 OF 256K

16 OF 256K

256 OF 256K

(1) All 200 line modes are double scanned for 400 line resolution. (2) The VGA implementation of these modes is the default.

VIDEO SIGNALS

Vertical Horizontal sync Resolution Frequency Polarity 350 lines 31.5 KHz + 400 lines 31.5 KHz - 480 lines 31.5 KHz - 600 lines* 35.2 KHz -

Vertical sync Frequency 70.1 Hz - 70.1 Hz + 59.9 Hz - 56.2 Hz -

*Requires an Analog MultiSync compatible monitor.

BLOCK MEMORY MAP Standard Memory

640 KBytes range 0 to 655360 decimal (Oh to 9FFFFh) 384 KBytes range 1048576 to 1441792 decimal (100000h to 160000h) The top 384 KBytes of memory can be disabled to function with third party add on boards.

KEYBOARD FEATURES

standard United States ASCII 101 International 102 key optional Dvorak

Polarity

PC40-III SERVICE MANUAL

STANDARD CGA (1) VGA (1) & (2) CGA

VGA (1) & (2) VGA (1)

VGA (1)

VGA

VGA VGA/MCGA VGA VGA/MCGA (1)

Special keyboards and drivers are available to customize the keyboard for the following countries. Germany, Spain, France, Italy and the United Kingdom.

ADDITIONAL FEATURES Numeric keypad

4 cursor keys in an inverted T formation

OTHER FEATURES

Security lock for keyboard lock out

Built in speaker

External Configuration switches

Battery backed-up real time clock/calendar. Metal Case (can support monitor)

MultiSync is a registered trademark of NEC

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PC40-III SERVICE MANUAL

SPEED SELECTION One of the three operating speeds is selected by either a program or by the operator.

Default speed is 6 MHz. The operator or program can change the speed by issuing the following command strings.

Control Alternate S for standard 6 MHz Control Alternate T for turbo 8 MHz Control Alternate D for double 12 MHz

PHYSICAL SPECIFICATIONS

Height 5.75 inches 14.6 cm Depth 15 inches 38.1 cm Width 14 inches 35.6 cm Weight 21 pounds 9.55 Kg Minimum Clearances

Right side 4 inches 10.2 cm Back side 4 inches 10.2 cm ENVIRONMENT SPECIFICATION

ENVIRONMENTAL —temperature— Operational 4 to 40 C. (+39 to +122 F) Storage —40 to +60 C. (-40 to +160 F) Gradient +10 C/Hour (+18 F/Hour) —humidity— Relative 8% to 80% RH (no condensation) Gradient 20% per Hour (no condensation) Wet Bulb 26 C, 78 C (no condensation), maximum

VIBRATION Operational 0.048 in. Dbl. Amplitude (5 - 17 Hz) 0.73 G, 17 - 150 Hz

0.33 G, 200 to 500 Hz use linear interpolation for acceleration levels between 150 Hz and 200 Hz

Non-Operate 1.0 G, 5 - 2000 Hz, sweep of .067 decades/minute

SHOCK Operational 10 G, 11 mS Half Sine Wave; any axis. Non-Operate 50 G, 25 mS Square Wave; any axis.

25 G, 25 mS Square Wave; heads over data.

ALTITUDE Operational — 457 to 2,972 Meters (— 1,500 to + 9,750 Ft) Non-Operate — 457 to 12,192 Meters (—1,500 to +40,000 Ft)

ACOUSTIC NOISE 45 dBA at 1 meter

REGULATORY APPROVALS:

STANDARD DESCRIPTION USA/Canada:

UL 478

Electronic Data Processing Units and Systems

FCC FCC Class B, Part 15 Subpart J CSA 22.2 Data Processing Equipment, Consumer and Commercial Products. EUROPE

VDE IEC 435

PC40-IIT SERVICE MANUAL

SECTION 2 THEORY OF OPERATIONS e SYSTEM BLOCK DIAGRAM . e SYSTEM OVERVIEW e NOTES — OPERATIONS GUIDE

PC40-I1I SERVICE MANUAL

SYSTEM OVERVIEW

(To be released)

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PC40-III SERVICE MANUAL

NOTES FROM OPERATIONS GUIDE AUTOCONFIG™

AUTOCONFIGuration is a unique feature of Commodore PC personal computers like the PC40-III, allowing the computer to automatically sense additional peripheral devices plugged into the expansion bus. Once these additional devices are detected, the resident peripherals on the PC40-III motherboard are adjusted so as not to conflict with expansion peripherals. The AUTOCONFIG™ feature can prevent hardware damage to peripherals and motherboard, as well as ease the installation of expansion cards.

The AUTOCONFIG™ process is described in this section.

Video

The PC40-III first examines the expansion bus for any expansion Advanced Video Adapter BIOS in the OC0000h — OC7FFFh memory range. If an expansion video BIOS is found, then an external VGA or EGA controller is assumed to be on the bus and the onboard VGA controller is disabled to avoid conflict. If an expansion video BIOS is not found, the video output is configured in accordance with the default CONFIG Control video setting, as defined by the CONFIG dip switches 1, 2 and 3.

You can add an expansion MDA or CGA compatible controller in conjunction with the onboard VGA controller or provide two video screens. (This makes many CAD packages easier to use.)

NOTE: When using the PC40-III’s onboard video controller, a VGA compatible monitor such as Commodore Models 1403 and 1450 (monochrome) or 1950 (color) must be connected to the 15 pin video output connector (no matter what video mode you have selected).

If you want to use two video screens, there are several things you should remember. First, you should use a CGA, MDA or compatible adapter — one that has no BIOS ROM of any kind.

Also, if you were to use an MDA/Herc adapter (monochrome) and you have the CONFIG switches set for VGA color, the PC40-III will boot using your VGA monitor and you will see a blinking cursor on your monochrome monitor, indicating that it has been initialized. If, while using the MDA/Herc adapter in the expansion port, you have the CONFIG switches on the back of the System Unit set to MDA/Herc, your PC40-III will use the monochrome monitor as the boot monitor and the VGA monitor will be initialized with the blinking cursor.

In either case, you can switch between the VGA and the monochrome monitors by using the MS-DOS MODE command. The syntax for the MODE command is as follows:

¢ MODE MONO — sets the MDA as the default monitor ¢ MODE co80 — places the onboard VGA adapter into 80 column mode and sets it as the default monitor

¢ MODE co40 — places the onboard VGA adapter into 40 column mode and sets it as the default monitor

Serial Port (COMn:)

Before the onboard serial port is enabled a scan of the two standard COMn: hardware locations is made. If serial hardware (serial card/modem) is found operational, possible bootup message(s) may be:

EXPANSION COM at 03F8h and/or EXPANSION COM at 02F8h

If both available COM: addresses are occupied by expansion boards, then the onboard serial port will not be enabled. The onboard serial port will be configured and tested at I/O address 03F8h if no expansion COM:’s are found and will be con- figured and tested to the unused COM: address if only one expansion COM: is found.

If the onboard serial port is configured and tested successfully a message will be output during bootup: ONBOARD COM at 03F8h or ONBOARD COM at 02F8h

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PC40-IIT SERVICE MANUAL

Parallel Port (LPTn: or PRN:)

Before the onboard parallel port is enabled a scan of the three standard LPTn: hardware locations is made. If parallel hard- ware (e.g., a printer card) is found operational, possible bootup message(s) may be:

EXPANSION LPT at 0378h and/or EXPANSION LPT at 0278h and/or EXPANSION LPT at 03BCh

If all available LPT: addresses are occupied by expansion boards, then the onboard parallel port will not be enabled. The onboard parallel port will be configured and tested at I/O address 03BCh if no expansion LPT:’s are found, and will be con- figured and tested to the unused LPT: address if two expansion LPT:’s are found. If only one expansion LPT: is found, the onboard parallel port will be enabled to the first available I/O address, when searching in the following sequence:

03BCh, 0378h, 0278h If the onboard parallel port is configured and tested successfully, a message will be output during bootup: ONBOARD LPT at 03BCh or ONBOARD LPT at 0378h or ONBOARD LPT at 0278h

Mouse Port Acheck is made for a standard Microsoft Bus Mouse. If it is found in the I/O channel then the onboard Microsoft compatible mouse hardware is never enabled. The following message will appear during bootup: EXPANSION MOUSE at 023Ch If no expansion mouse is found the onboard mouse is enabled and tested. If mouse is operational then the following message will appear during bootup: ONBOARD MOUSE at 023Ch

NOTE: The onboard mouse hardware is enabled/tested independent of the presence of the actual mouse. The bootup messages will appear even if the Commodore PC Mouse Kit is not attached.

80287 Numeric Coprocessor A test is made for the presence of an 80287 Numeric Coprocessor during bootup. If an 80287 is detected the following message will be output:

80287 Numeric Coprocessor NOTE: 80287 coprocessors are available in 5, 6, 8 and 12 MHz speeds. However, the units are downwardly compatible only — for example, an 8 MHz coprocessor will function if the PC40-III is running at 6 or 8 MHz, but a 6 MHz unit will not function properly if the PC40-ITI is running at 12 MHz. In order to use the 80287 at all three CPU speeds (6, 8, 12 MHz), an 80287-8 (an 8 MHz part) is necessary.

NOTES FOR THE PROGRAMMER It is possible to override the configuration done at bootup. We STRONGLY recommend that only advanced programmers with experience with low-level hardware/software interaction attempt this.

NOTE: If software override of the default configuration is performed, the presence of any expansion hardware should be taken into account to prevent hardware conflict resulting in damage of the expansion hardware or the PC40-III motherboard.

Configuration is performed via the COMMODORE CONFIGURATION REGISTER at I/O address 0230h. This register is read/write with only bit7 changing its meaning from read to write. The register values are shown in the following table.

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PC40-III SERVICE MANUAL

COMMODORE CONFIGuration REGISTER — I/O addr 230h

mono — indicates that the onboard video adapter is setup as a monochrome adapter when high, color when low. venb’ — when set low the onboard video adapter will be enabled.

rte © — when set high the onboard real-time clock will be enabled.

x — this bit is reserved for future use.

mouse — when set high the onboard mouse will be enabled.

coml1 _com0 Iptl__1ptd low low — onboard serial port is disabled. low low — onboard parallel port is disabled.

low high — serial port enabled at I/O addr 02F8h low high — parallel port enabled at I/O addr 03BCh high low -— serial port enabled at I/O addr 03F8h high low — parallel port enabled at I/O addr 0378h high high — this configuration is reserved. high high — parallel port enabled at I/O addr 0278h

THE PC40-11 HARDWARE CONFIGURATION Using the PC40-III Setup Utility

Once MS-DOS has finished booting and the C> prompt has appeared, you can use the built-in Setup utility to give the system detailed information on your PC40-III configuration. To run the Setup utility, hold down the Control and Alt keys and simultaneously press the Esc key. The main menu of the Setup utility will appear and will look like this:

Commodore Setup Utility

Date 23.08.88 Hard Disk Type Information

Time 14:23:08 Diskette 1 1.2M Diskette 2 NONE Hard Disk 1 28

Sma dceuit 940 17 512 940 62MB : 940 17 512 940 46¢B

oprocessor NONE 615 17 NONE 615 20MB Base Memory 640 KB 462 17 256 511 30MB Extended Memory 584 KB 733 17 NONE 733 30MB Base memory found: 640 KB 900 17 NONE 901 112MB Extended memory found: 384 KB 820 17 NONE 820 20MB Use |, | to select items 855 17 NONE 855 35 MB Use +,¢ to select predefined 855 17 NONE 855 49MB values 306 17 128 319 20MB Use <PgDn> to view more hard disk 733 17 NONE 733 42MB types 0 0 0 0 0 MB Press <Esc> to abort SETUP 612 17 0 635 20MB Press <End> to exit and update

Type Cyln Head Sect W-pc L-zone Size 306 17 128 305 10MB 615 17 300 615 20MB 615 17 300 615 30MB

PON DNIANNANYNDWhDOODHD HS H&

COMMODORE SETUP UTILITY MAIN MENU

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PC40-III SERVICE MANUAL

As noted on the Setup screen, you can use the cursor keys and the keyboard to define or change the system configuration, as follows:

¢ Use the up and down cursor keys to move from option to option in the main menu.

Following is specific information about the various Setup menu options.

Setting the Date and Time for the Real Time Clock/Calendar

The PC40-III has a Real Time Clock/Calendar with a battery backup. This means that once set, the clock/calendar will keep the correct date and time even when the computer is turned off. You use the first two lines of the Setup Utility to set the Real Time Clock/Calendar, as follows:

Date: Allows you to set the correct date into the Real Time Clock. This option does not have any predefined entries; simply enter the date from the keyboard, in the format dd/mm/yy.

Time: Allows you to set the correct time into the Real Time Clock, without invoking MS-DOS. This option also does not have any predefined entries; simply enter the time from the keyboard, in the format hh:mm:ss, where hh = 00-23,mm =00-59,and ss = 00-59.

Setting the Floppy Disk Drive Options

You can have a maximum of two floppy diskettes configured into your PC40-III. The next two Setup menu options, Diskette 1 and Diskette 2, allow you to tell the system how many floppy drives are available and what type they are. Here’s how to set these options:

Diskette 1: Predefined entries: None, 360 Kb 5.25, 1.2 Mb 5.25, 720 Kb 3.5, 1.44 Mb 3.5. The floppy drive in your PC40-III is always considered Diskette 1. Since PC40-III is equipped with a high density (1.2 MB) drive, select 1.2 Mb 5.25 for Diskette 1. Diskette 2: Predefined entries: None, 360 Kb 5.25, 1.2 Mb 5.25, 720 Kb 3.5, 1.44 Mb 3.5. If you have not installed a second floppy drive in your PC40-III, select None for Diskette 2. If you have installed a second floppy drive, select whichever drive type (360 Kb 5.25, 1.2 Mb 5.25, 720 Kb 3.5, 1.44 Mb 3.5) applies to the installed drive.

Setting the Hard Disk Drive Options

Hard Disk 1 and Hard Disk 2, the next two options in the Setup utility, define how many hard disk drives are available and what kind of hard disk drives they are. Hard disk drives are identified by a pre-assigned Drive Type (1, 2, etc.). This number tells the PC40-III the drive manufacturer and capacity.

Commodore Setup Utility

Date 23.08.88 Hard Disk Type Information

Time 14:26:26 Type Cyln Head Sect W-pc L-zone Size Diskette 1 1.2 17 977 17 300 977 40MB Diskette 2 NONE 18 977 17 NONE 977 56MB Hard Disk 1 28 19 1024 17 512 1023 59NB Hard Disk 2 NONE 20 733 17 300 732 30NMB Video SPECIAL 21 733 17 300 732 42MB Coprocessor NONE 22 733 17 300 733 30MB Base Memory 640 KB 23 306 17 0 336 10MB Extended Memory 384 KB 24 805 26 O 820 40MB Base memory found: 640 KB 25 776 33. =«-0)~=— 800 «100 MB Extended memory found: 384 KB 26 745 28 0 800 40MB Use ft, | to select items 27 625 a") eh. a Use >,< to select predefined 28 17 1000 40 MB

0

anh orhhonyndanryio

values 29 965 10 17 1000 80 MB

Use <PgDn> to view more hard disk 30. 782 064 «(28 800 42MB types 31 00 O 0 OMB

Press <Esc> to abort SETUP 32 00 0 0 OMB Press <End> to exit and update

SETUP UTILITY PULLDOWN MENU FOR HARD DISK DRIVE TYPE 2-6

PC40-IIT SERVICE MANUAL

Here’s how to define your hard disk configuration:

Hard Disk 1: Your PC40-III comes equipped with a 40 MB hard disk drive. This drive is always considered Hard Disk 1. The Drive Type for this drive is shown on a sticker located on the back of your System Unit. Find this number and type it in after Hard Disk I.

The PC40-III Setup utility includes a menu of hard disk drive types with their individual ID numbers. You can page through the menu by pressing the PgDn key. For example, the opening Setup screen on Page 2-3 lists drive types 1 through 16. If you press PgDn, the Setup screen will be as shown on Page 2-4, with drive types 17 through 32 listed.

Hard Disk 2: This option is not supported by the onboard controller.

Other Setup Options

Video: Tells system what the default video is. Factory-set default is special. To change this setting, see the permissible default modes listed in Appendix H.

Coprocessor: Tells system if an 80287 Numeric Coprocessor (NCP) is installed. Factory-set default is mone. Select Yes if you have installed an 80287 Numeric Coprocessor (see Appendix N for information on using an 80287 Numeric Coprocessor). Base memory: Lets you customize base memory for specific applications.

Extended Memory: Tells system how much extended memory is available. The default 384 Kbytes of extended memory can be enabled or disabled as required by setting the CONFIG Control dip switch 4.

SETTING THE MICROPROCESSOR CLOCK SPEED

The 80286 microprocessor in the PC40-III is capable of running at three different clock (i.e., processor or CPU) speeds: e Standard speed = 6 Mhz ¢ Turbo speed = 8 MHz © Double speed 12 MHz

The PC40-III is preset to the standard 6 MHz speed. You can switch between the clock speeds by using special key combina- tions or by using the MS-DOS ATSPEED command.

To set the clock speed from the keyboard, use these key sequences: e CTRL-ALT-S for standard speed (6 MHz) ¢ CTRL-ALT-T for turbo speed (8MHz) e CTRL-ALT-D for double speed (12 MHz) NOTE: Some software may require that you select standard or turbo speeds for normal operation. To set the clock speed using the ATSPEED command, first make-sure the MS-DOS prompt is showing on the screen. Then

type the word ATSPEED, followed by a space, a dash (—), and then a letter (S, T, or D) denoting the desired speed. For instance, if you are in standard speed and you want to change to turbo speed (8 MHz), type the following and press Enter:

ATSPEED —T Extended Memory Dip Switch Dip switch 4 enables or disables the 384K of extended memory in the PC40-III.

ENABLE EXT. MEM. [if DISABLE EXT. MEM. 4

THE RESET SWITCH

The Reset switch protrudes slightly on the right side of the machine, just behind the keyboard connector. The switch provides an alternative to cycling power when an application program may have ‘‘crashed”’ the computer. Pressing this switch will effectively reboot the computer as if the power had been cycled OFF and then ON. All information in the computer’s RAM memory will be lost. Be careful not to press this button during disk access, or you may lose information that was being written to mass storage devices (e.g., hard disks or floppy disks) while the switch was depressed.

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PC40-III SERVICE MANUAL

OOFFFF 0A0000

OBFFFF 0c0000

OCFFFF 008000

1MB OEFFFF 0F0000 INTERNAL USE 0F8000 32K AT ROM BIOS OFFFFF 100000 384K RAM (EXTENDED MEMORY) 1SFFFF 15MB

PC40-I11 MEMORY MAP

PC40-III SERVICE MANUAL

JUMPER SETTINGS ON MOTHERBOARD

PAD 301 JMP 903 PAD 302 JMP 904

Jumper Locations on Motherboard

| JUMPER _ FUNCTION DEFAULT RESULT JMP 903 Disable HD Not Installed HD Installed

JMP 904 HD Type Location A Conner HD

Location B Quantum HD PAD 301 80287 Clock Mode | +3Mode 8 MHz Part runs up to 12 MHz PAD 302 80287 Clock Speed CPU Clock (+3) 8 MHz Part runs up to 12 MHz

PAD 301 & PAD 302 may be changed to take full advantage of using a 12 MHz 80287. This is a dealer installation only.

IRQ Vectors Used in the PC40-IiT

PC40-III SERVICE MANUAL

There are two interrupt controllers on the PC40-III:

CPU Interrupt

Cascade 2

IRQ 0 — System Timer (built-in)

1 — Keyboard (built-in)

2 — Cascade #2

3 — COM2 (built-in or expansion)

4 — COMI (built-in or expansion)

5 — XT Compact HD (unused)

6 — Floppy (built-in)

7 — LPT1,2,3 (All ports: built-in plus expansion)

IRQ 8 — Real Time Clock

9 — Onboard Mouse

10 — Unused 11 — Unused 12 — Unused 13 — Unused 14 — AT Hard Disk (built-in or expansion) 15 — Unused

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PC40-III SERVICE MANUAL

SECTION 3 TROUBLESHOOTING GUIDE

TECHNICAL SERVICE NOTES

IMPORTANT:

¢PC40-III PCB’S RETURNED FOR CREDIT MUST BE SHIPPED IN AN ANTI-STATIC BAG, AVAILABLE THROUGH THE COMMODORE PARTS DEPT. ANY PCBS RETURNED FOR CREDIT BY SERVICE CENTERS WHICH ARE NOT PACKAGED CORRECTLY WILL BE SENT BACK TO THE SERVICE CENTER AND NO CREDIT WILL BE ISSUED.

¢PC40-III HARD DRIVES RETURNED FOR CREDIT MUST BE INSERTED IN AN ANTI-STATIC BAG AND PACKED IN A COMMODORE SPECIFIED HIGH DENSITY FOAM SHIPPING BOX, BOTH AVAILABLE THROUGH THE PARTS DEPT. FAILURE TO DO SO WILL VOID WARRANTY.

COMPONENT REPAIR:

PC40-III MAIN BOARD IS A MULTI-LAYERED PCB ASSEMBLY. COMPONENT REPAIR BEYOND THE SOCKETTED CHIP LEVEL RESULTING IN NON-REPAIRABLE DAMAGE WILL VOID WARRANTY. USE STATIC PRECAUTIONS WHEN SERVICING THIS PCB ASSEMBLY.

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PC40-III SERVICE MANUAL

TROUBLESHOOTING ERROR MESSAGES

Error Messages

. DMA 1 error

. DMA 2 error

. Interrupt controller 1 error

. Interrupt controller 2 error

. PIO error

. Parity error

. Real time clock is not working . Illegal shutdown code in CMOS

. Virtual Mode CPU error

Parity error on main circuit board Parity error on expansion bus Non-recoverable error-Processor halted Press F1 key to continue

Battery Failure

Base memory configuration error Extended memory configuration error Floppy 0 configuration error

Floppy | configuration error Coprocessor (80287) configuration error The realtime clock has not been initialized Keyboard

Key switch is off. Turn it on to continue

Boot failure, check disk and hit any key to try again

Troubleshooting Guide

Customer Response See your dealer

See your dealer See your dealer See your dealer See your dealer See your dealer See your dealer See your dealer. See your dealer See your dealer See your dealer See your dealer Press F1 key Run Setup Utility/See your dealer Run Setup Utility Run Setup Utility Run Setup Utility Run Setup Utility Run Setup Utility Run Setup Utility Check keyboard Turn keylock on

Check for non-MS-DOS disk in Drive A:; run Setup Utility

Test OB Test 0C Test OD Test OE Test OF Test 10 Test 1E Test 02 Test 26 Misc Misc Misc Misc Test 11 Test 17 Test 18 Test 1A Test 1A Test 1D Test 1E

Test 14

Misc

Service POD Test (H)

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PC40-II SERVICE MANUAL

POWER ON DIAGNOSTICS

PC40-III Trouble Shooting — Section 3

The Commodore 80286 ROM bios contains a ‘‘Power on Diagnostic’? program which tests the functions of hardware and checks the configuration prior to passing control to the operating system.

The number of the test routine being run is passed to addr 03 78 (H) prior to the start of each test section.

The 80286 processor is initialized by the ‘‘RESET”’ signal. Refer to RESET description in IC pinout section, note that ““VCC”’ and “CLK” to CPU must be correct and ‘‘HOLD”’ must not be active for 34 ticks from leading edge to trailing edge of initial reset.

RESET will terminate all instruction execution and local bus activity until it is negated. Prior to fetching, decoding and executing, the first instruction, located at physical address FF FF FO (H), the 80286, in real address mode, processes some micro code located in its internal ROM, this takes about 38 ticks.

Test 01 (H) 0000 0001 (B)

The first test performed by the power on diagnostic checks the 8088 flags, the arithmetic logical unit, and the CPU registers. If a failure is detected in Test 01, a ‘‘HALT”’ instruction is executed. This will stop program execution and prevent the CPU from using the local bus. The 80286 can be forced out of the halted state by ‘‘RESET”’’, ‘NMI’ or “INTR”’ (when “INTR”’

is used for RESTART, the interrupt enable bit of flag register must be on (set to 1), and the effective address computed from CS:IP will point to the next instruction after the halt instruction).

***Failure in test 01 indicates defective 80286.

Test 02 (H) 0000 0010 (B)

This routine checks to see if a ‘“SHUTDOWN”’ has occurred. A shutdown can indicate a severe error which would prevent

the CPU from further processing.

NOTE: A halt or shutdown condition is signaled externally, by the 80286 as a bus operation. Low states on SO’, SI’, COD/INTA’, and a high state on M/IO’ indicate a halt or shutdown. The state of address line 1 will indicate which condition, Al high is halt, Al low is shutdown.

After the test number is moved to the parallel port a check for keyboard reset is conducted and the program branches to test

04 (H) if it has.

The check for shutdown begins by examining the 8242 keyboard controller status port. In all ten shutdown conditions are

tested, of these, three unexpected shutdown conditions, numbers 6, 7 or 8, any one of which if true, will generate the console

message: ‘Illegal Shutdown Code in CMOS”’

NOTE: Branch information for shutdown routines are stored in CMOS memory. The shutdown command is sent to the 8242, the UPI status port, which will halt the CPU. Return depends on the shutdown code in CMOS memory.

An error code, F6, F7 or F8, (HEX) is sent to the parallel port before calling the display routine which generates the above message.

In real address mode a shutdown could occur under the following conditions:

Interrupt number 8, interrupt number 13, or a ““CALL INT’’ or ‘‘PUSH”’ instruction which wraps stack segment when SP is ODD.

Routines also perform valid shutdowns to exit protected mode. During these the DMA page register will be initialized and interrupt control words (ICW) 1, 2, 3 and 4 will be reinitialized. Other routines within the test enable ‘‘NMI’’, parity and set the I/O check bit.

***Failures in test 02 could indicate problems on the local bus, or expansion bus. This would include: 80286, FE3000, FE3010, or any third party cards.

Test 03 (H) 0000 0011 (B)

Eprom checksum test verifies contents of eprom by adding bytes and checking for result of zero. A compensation byte is fac- tored into the addition to make the sum zero.

Detection of an error results in a halt condition and would invalidate tests 01 and 02. ***Failure in test 03 indicates defective ROM.

PC40-III SERVICE MANUAL

Test 04 (H) 0000 0100 (B) Test 04 checks the DMA page registers by writing and reading bits starting at address 80 (H). ***Failure in test 04 indicates possible defective FE3010, or local bus.

Test 05 (H) 0000 0101 (B) Timer 1 and timer 2 are checked for correct operation. Interrupts are masked off during the test. ***Failure in test 5 indicates possible defective FE3010.

Test 06 (H) 0000 0110 (B)

Memory refresh test. Timer and DMA are setup to initiate refresh cycles every 15.1 microseconds. Size of virual memory is calculated.

***Failure in test 06 indicates possible FE3010, Refresh logic or memory problem.

Test 07 (H) 0000 0111 (B) Test 07 checks the 8242 keyboard controller by writing and reading the keyboard buffers. ***Failure in test 07 indicates possible defective 8242 or associated circuitry.

Test 08 (H) 0000 1000 (B)

Test 08 writes and reads the first 128K of RAM and verifies block size is 128K. First pass writes addresses into data, the second pass writes the complement of the address into data. Memory is cleared after test. The battery status is also confirmed in test 08.

***Failure in test 08 indicates possible defective RAM or RAM logic.

Test 09 (H) 0000 1001 (B)

Test and configure video. A search is made to determine if MDA, CGA or a special video adapter is configured, if not the onboard VGA is enabled and a call to VGA bios is executed. The dip switches are read to determine the default video mode.

NOTE: The mode register setting in the 5720 controls the reset signal to the onboard VGA controller chip. If no special video adapters are found on the expansion bus then ‘‘NOVID’”’ from the 5720 to the PVGA is negated.

On completion of this test the title and copyright message are displayed.

Test 0A (H) 0000 1010 (B) Test RAM from 128K to 640K. A display message is generated indicating that the base RAM of 128K, Test 08, is OK.

Blocks of 128K, starting at 128K are then tested by writing, reading and verifying RAM. The first pass writes addresses to data, that is, the address which defines the physical location is also used as the bit pattern that is being written. The second pass writes complement of address into data.

The test displays results in blocks of 128K to the console each time a 128K boundary is reached.

At completion of the onboard memory test the CPU is placed in virual mode and a test for virtual memory (over 1 MEG) is started. NOTE: See test 26 (H).

***Failure in test OA indicates a defective RAM.

Test 0B (H) 0000 1011 (B) DMA controller #1 register check.

NOTE: Appendix L of the PC40-III operator guide lists error messages starting with this test, see page 85 of operations guide part number 319983-01.

Four current address registers (16 bits wide, each) and four current word count registers (16 bits wide, each) for each of the four DMA channels are written to and read from to verify operation.

A failure in test OB will generate the following display on the console: ‘SDMA I error’

The beeper will sound, and a halt instruction will be executed.

***Failure in test OB indicates A defective FE3010.

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Test OC (H) 0000 1100 (B) DMA controller #2 register check. The second functional 8237 containing four current address registers (16 bits wide, each) and four current word count registers (16 bits wide, each) within the FE3010 are written to and read from to verify operation.

Successful completion of the test OC will set the modes for DMA channels 0 through 3 and enable cascading by channels 4, 5 and 6 (DMA 1). : : A failure in test OC will generate the following display on the console: ‘SDMA 2 error’’ The beeper will sound, and a halt instruction will be executed. ***Failure in test OC indicates a defective FE3010.

Test 0D (H) 0000 1101 (B)

Interrupt controller #1 test. Patterns are written to, and read from the interrupt mask register (IMR) which controls the inter- rupt request register (IRR).

A verification is made that no interrupts can occur if ‘‘IMR”’ is set to FF (H). A vector is initialized to a temporary interrupt service routine in the event of a failure.

A test for correct timer 0 interrupt is also made.

A failure in test OD will generate the following display on the console: ‘Interrupt controller 1 error’’

The beeper will sound, and a halt instruction will be executed.

***A failure in test OD indicates a defective FE3010.

Test OE (H) 0000 1110 (B) Interrupt controller #2 test. The second functional 8259 contained in the FE3010 is tested as in test OD, without timer test. A failure in test OE will generate the following display on the console: ‘Interrupt controller 2 error’’ The beeper will sound, and a halt instruction will be executed. ***A failure in test OE indicates a defective FE3010.

Test OF (H) 0000 1111 (B)

Check peripheral in/out register. Write and read from PIO register.

A failure in test OF will generate the following display on the console: **PIO error’

The beeper will sound, and a halt instruction will be executed.

***A failure in test OF indicates a defective FE3010.

Test 10 (H) 0001 0000 (B)

RAM parity test. Blocks of RAM are written to and read from, parity check for odd parity is made. Parity disabled after successful test.

NOTE: PC40-III does not use parity, third parity boards that use parity will enable parity.

‘NMI’? is enabled and a service routine for a parity error generates the following console message. ‘‘Parity error’

The beeper will sound, and a halt instruction will be executed.

***Failure in test 10 indicates a defective RAM, third party card, NMI, or local bus.

Test 11 (A) 0001 0001 (B) Test CMOS clock for battery failure and checksum failure. Beeper will sound if failure is detected. Console will display: ‘‘Battery failure’? or ‘“CMOS checksum failure’? or both. ***Failure of test 11 indicates a defective battery, defective oscillator, or M146818A.

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Test 12 (H) 0001 0010 (B) This test is disabled. It is used only in manufacturing tests.

The beeper will sound for a set length prior to the start of test 13 (H). In a system which has passed all tests to this point the beeper sound heard now would be the one heard in the power up routine.

Test 13 (H) 0001 0011 (B)

Setup interrupt controller and move vector tables to RAM. Vector addresses are fetched from top 8K module. NOTE: Vectors for video were setup in test 09.

Master and slave interrupts are enabled at this point.

Test 13 does not create any error messages.

Test 14 (AH) 0001 0100 (B)

Keyboard test. Functional test of the 8242 keyboard controller at U203. A test for a stuck key on keyboard is performed. Check is made to see if key lock is locked.

A failure in test 14 will display the following error message on console: ‘*Keyboard error’’ ***Error indicates a defective 8242 controller or a defective keyboard.

Test 15 (H) 0001 0101 (B)

Test and configure the parallel port. Parallel port addresses are setup, reads and writes to ports are done. Set time out. No error messages are generated by this test.

NOTE: PPC1 at U602 controls parallel output.

Test 16 (H) 0001 0110 (B) Configure serial COM1 and COM2 for 8250 at U604. Read serial interrupt ID, set number of serial channels. No error messages are generated by this test.

Test 17 (FD) 0001 0111 (B) Configure memory less than 640K. Parity (for EXPANSION RAM) is enabled.

Memory was tested in test OA, and ‘““CMOS STATUS”? set. A check for a warm boot (ALT/CNTRL/DEL) is made and a comparison of the old and new memory configuration is performed. If a memory size mismatch is detected, the beeper will sound and the following non-fatal error message will be displayed on the console:

‘*Base memory configuration error’ The new configuration is stored. ***Check the settings for RAM size in the setup utility if you encounter this message.

Test 18 (H) 0001 1000 (B) Configure memory over 1 megabyte (virtual memory). Check is made on address line 20, a low indicates virtual address mode.

CMOS status is checked as in test 17, a memory size mismatch will sound the beeper and generate the following non-fatal error message on the console:

‘*Extended memory configuration error’ The new configuration is stored. ***Check the settings for RAM size in the setup utility if you encounter this message.

Test 19 (H) 0001 1001 (B) Configure keyboard test. Setup keyboard buffers, enable keyboard interrupt and test if key switch is turned to the on position. If the key switch is off the following message