Tandy 1000SX Technical Service Data

HOWARD

W. SAMS

&

COMPANY

COMPUTERFACTS

Technical

Service Data

TANDY®

MODEL

1000SX

COMPUTER

FEATURES COMPLETE

SCHEMATICS •

PRELIMINARY

SERVICE CHECKS

•

TROUBLESHOOTING

TIPS

EASY-READ

WAVEFORMS

•

REPLACEMENT

PARTS

LISTS •

SEMICONDUCTOR CROSS REFERENCE

giMflC

COMPUTERFACTS"

TANDY

MODEL

1000SX

PRELIMINARY

provides the user with a

data

This

service

tion and repair

tions.

Check all

nection

tool

which is

interconnecting cables for

and correct hook-up

SERVICE CHECKS

designed for quick

of Computer

time-saving

system malfunc-

good con-

before making

Isola-

service checks.

Always

or disconnecting
erals.

x

ca

o

O

v.

°

Q
<

uj

I-

Q

o

s

Disconnect al

Computer system to

ma I functions.

Replacement or repair of the

System Board, Keyboard, Disk Drives or

nectors

has been isolated.

turn

may

TEST EQUIPMENT

Computer Off before connecting

the

connectors,

external peripherals

I

boards or

eliminate possible external

Power Supply,

necessary after the

be

AND

TOOLS

malfunction

periph-

from the

con-

o

TEST EQUIPMENMT

o

Digital Volt/Ohm Meter

Probe

Logic

Frequency

Counter

Monitor with Audio Input

Disk Drive Tester or Test

Program

TOOLS

Head Cleaning

Contact and Switch

Phillips

Flat Blade Screwdriver

1/4"

Insertion and Removal Tools 20,

IC

pin

Low Wattage

Deso

^ttb ^bb in ^Bt

m MMMlm

The fisting

constitute in any

by Howard W. Sams

such replacement part. The numbers of

compiled from information furnished

by the manufacturers of the particular

listed.

**s$^

Howard

'm

4300 West 62nd Street,

any

of

available replacement part herein

recommendation, warranty

case a

& Co. as to

the quality

87CS19008

Equipment

Screwdriver

Socket

28

16,

14,

Soldering Iron

i

ng

Eq

u

I

der

W. Saras

does not

or guaranty

and suitability of

these parts have been

to Howard W. Sams

type of replacement part

DATE

& Co.

9-87

Cleaner (non-spray type)

24 and 40

pme nt

Co.

&

P.O. Box 7092, Indianapolis, Indiana

Reproduction or

torial content, in any manner, is prohibited. No patent liability is

assumed with

© 1987 Howard W. Sams &

4300

West

U.S.A.

without express permission, of editorial

use,

the

respect to

62nd

Street, P.O. Box 7092,

of the information contained herein.

use

46206 U.S.A.

Co.

Indianapolis, Indiana

Printed in U.S. of America

or

46206

pic-

MISCELLANEOUS ADJUSTMENTS

POWER

SUPPLY

NOTE:

Do

not operate

the Power

Supply

without

a load.

5V ADJUSTMENT

12V

ADJUSTMENT

NOTE:

Perform

the 5V

Adjustment

first.

Con-

nect the

Input

of a voltmeter

to pin 7

of Con-

nector

SK3-1.

Adjust

the 12V

Adjust

Control

for

a voltage

of 12.0V.

Connect

the

Input

of

a voltmeter

to

pin 9

of

Connector SK3-1

.

Adjust

the

5V

Adjust

Control

(VR1)

for a voltage

of 5.0V.

VR1

VR2

5V

12V

ADJUST

ADJUST

F1

:ib.

CN

(3B)

KEYBOARD

INTERCONNECTING

DIAGRAM

II

PRELIMINARY

SERVICE CHECKS

(Continued)

UAj

v

-^

COMPOSITE

AUDIO VIDEO

RGB

VIDEO

/

*

' * *

\

(

a a

mao

)

B1A1B1

A181Al B1

A1 B1 A1

J10B J10A

J15

J14 J13

J12 J11

J9

S.OV©

1

t

. .

.

(8B)

4.77MHz,N0RMAL

7.16MHz,TURB0

J6

12

U51

B31

A31

B31

A31 B31

A31 B31 A31

831

A31

®

SEE

SWITCHES

S2 AND JUMPERS'"

U41

ROM (1D)

VIDEO SYSTEM (4C)

RAM 128K

v^

U3B

CPU

®

U35

3EU

E4F^lE3

U24

]

P

5

i

SB)

(3C) (BE)

R26A

VOLUME

U22

SYSTEM

BOARD

LIGHT

PEN

*ezz3'.

Y

LOW,NORMAL,

HIGH,TURBO

51

~EJ-

J4

J3

J2

RESET

J8

©

u

J7

33

E6

E5

U55

®

J5

U37

BE

U37A

®]

2A)

BANK

1

BANK

2SBK 25SK

RAM

RAM

SP1

8a Z

*!©

JOYSTICK

PORTS

POWER

SUPPLY

SK3-1

SK3-2

SK2

©

(Ta) VR2

LD

VR1

5V ADJUST

(IB)

F1

v

-'

250V

3A

<J\P

SKI

6C

(£2)

i—n

sv

J2

l§

(SB)

1

s

2 6

J4

12

J9

2

11

J3

1

(SB)

|

6 J5

1

|

m

R1

(£)

U

L

1

4

J7

DISK DRIVE

A

BOTTOM VIEW

SI

-ofo-

_nnnn_

JT

_nnnrL_i

C27J.

i

.001

T

!

+

•Ve

_nnnn_i_

C28l

.001 T

120VAC

@

380BA

J1

11

2

U

r^?

i:

J2

S§

6B

1

s

2 S

J4

12

J9

2

11

J3

1

TP8Q

I

6

J5

1

1

R1

(Si

L_r

1

4

J7

DISK DRIVE

B

BOTTOM VIEW

TANDY

MODEL

1000SX

INTERCONNECTING

DIAGRAM

PRELIMINARY

SERVICE

CHECKS

(Continued)

LOW.

NORMAL

HIGH, TURBO

J4

R26A

J1

RAM

RAM

BANK1

BANKO

VI

III

PRELIMINARY

SERVICE

SERVICE

CHECKS

CHECKS

(Continued)

MATCH THE

THE

©

©

©

NUMBERS ON THE

NUMBERS

COMPUTER DEAD

(A) Check for

pin

tor J6 on

voltages are correct, go to

(D).

rect, check the adjustment of the

5V Adjust (VR1) and 12.0V Adjust

(VR2) Controls on the

Board,

ments."

(B) If the voltages are

nector

and disconnect the power connectors

from

Drive.

5.0V Source (pin 1 of Connector

and

(Pin 9 of Connector

Operating the

a load

Power Supply On and

voltages.

still

(C) If the correct voltages return, re-

connect the

System Board and Disk

a time until the Board or Drive

that
shutdown

sure

when connecting to the System Board

ON THE SERVICE

5.0V

8

and 12.0V at pin

the voltages are not cor-

If

see "Mi seel laneous Adjust-

J6, turn the Computer Off

the System Board and Disk

Connect a

#93 lamp to the 12.0V Source

a

may damage

missing, check

causing the Power

is

Power

at pin

the System

#1129 lamp

Power

the voltages are

If

Power

found. WARNING: Be

is

supply is

INTERCONNECTING

CHECKS TO

-12.0V

1,

9

of Connec-

Board.

Power

missing

J6). WARNING:

Supply without

it. Turn the

Fuse F1

Supply

Drives

If the

part

Supply

at Con-

to the

recheck

to the

one at

Supply to

turned Off

J6)

the

or Disk Drive.

(D)

Check the

(U41) by

SYSTEM BOARD

(A)

KEYBOARD

(A)

(B) Check the Keyboard cable and check

(C)

program runs for a while, then

A

suddenly stops or becomes

in operation. Check RAM

and

1 (IC's

Keyboard dead. Check Connector J4

on the System

tions.

Connector CN on the Keyboard for

good connections.

Check IC U22

substitution.

CPU

substitution.

IC (U36)

U1 thru U16).

Board

on the System Board by

good connec-

for

and ROM IC

erratic

Banks

IC

at

PERFORMED.

BE

(B)

(C)

©

©

©

SOUND

(A) No sound from the Internal Speaker

(B) No sound from the Internal

(C) If

DISK

(A) Disk Drive operation Is

(B) Check

(C) Drive dead. Check for 12V at

CD)

(E) If Switch S2-3

PARALLEL

(A) Paral

DIAGRAM AND

Check Video

tion.

Video display

Check Video

(U24,

IC's

(SP1) and

J10B. Check IC U37A by substitu-

tion.

(SP1).

Volume Control

Board.

Volume Control is set properly,

check Connector

for good

Speaker (SP1) voice coil for conti-

nuity.

DRIVE

Clean

Drive Spindle

Speed

and J9
tor J5

connections.

and 5V

the Drive Board.

are missing, check the Power

ply.

If the voltages are

nector J2, check the setting of

Switch S2-3 on the System Board.

It

IC's U22

Board

Connector J7

the

Check".

Connectors J1, J2, J4 thru

on

on the System Board for

at pin

should

by

PORT

lei

PHOTOS

(U30) by

IC

is

IC (U30) and Video RAM

U31, U34 and U35).

no audio at Connector

Check the setting

substitution.

Port

(R26A) on the System

J1 on System

connections and check

Drive

heads.

Speed, see "Spindle

the Disk

4

of Connector J2 on

set

be

On.

and

is set On,

U37 on the System

does not work, check

for good connections.

WITH

substltu-

not correct.

Speaker

of the

erratic.

Check the

Drive and Connec-

pin

the

If

present

voltages

at Con-

Board

J7

good

1

Sup-

check

VIDEO

(A) No video. Check Connectors J9 and

J10A for good connections and

the

Video cable

itor.

IV

going to

check

the Mon-

(B) Check

IC U55 by

substitution.

NORMAL/TURBO CPU

(D

(A)

PRELIMINARY SERVICE

CLOCK

Run the

the CPU

is pressed:

10 OUT 98,32:PRINT

20

AS=!NKEYS:IF

30 OUT 98,40:PRINT

40 AS=INKEYS:IF

following

clock speed

"NORMAL

AS=""

"TURBO

AS="" THEN 40

program to

each time

THEN 20

switch

(4.77MHz)"

(7.16MHz)"

ELSE 10

CHECKS

key

a

(B)

(Continued)

Check

mal"

set to "Turbo".

not correct,

Check

pin 16

to

speed set

quency does

U51.

for a logic

IC U22

with

and logic High

for

of

"Normal"

check IC

a frequency

IC U51 with

to

Low at

the speed

and

"Turbo". If

not

with

if the

U22.

7.16MHz

switch,

set

of

the

pin 37

to "Nor-

the

reading

4.77MHz

speed

with

the

check

of

speed

is

at

set

the

fre-

IC

DISASSEMBLY

CABINET

Remove

Slide cabinet forward

REAR

Remove three screws from lower rear of rear

panel.

up

DISK DRIVE REMOVAL

Slide

Disk Drive

left front, two

screw from right

Slide

nectors from

from

right side and two screws

Disk

bracket.

POWER

Unplug

Board and Disk Drives.

Remove four screws

Supply
chassis.

REMOVAL

two screws from lower

PANEL REMOVAL

Pull

out

to

clear

metal

tabs on top

on

shield out of

bracket.

screws from

bottom

the Drives forward

rear

Main Chassis.

Drive bracket

SUPPLY

REMOVAL

Power

to chassis

Supply Connectors from

and lift Power Supply

and up

bottom

to remove panel.

Remove

of Disk

of Drives.

Remove

to remove Drives

remove.

to

panel

of

slot on

left

two screws

left rear

Drive

and

unplug

Remove Drives

screws from

four

from left side

Remove rear

from rear holding

front

of cabinet.

and lift

side of

from

and one

bracket.

four con-

of

from

System

panel.

Power

out

of

INSTRUCTIONS

SYSTEM

Remove

four

remove

from

System
System

board

POWER

Remove

remove Fan. Grip

Power

disconnect Connector

chassis with On-Off

Remove

and

KEYBOARD

Remove nine

cabinet

Keyboard

BOARD

REMOVAL

D

i sk Dr

screws

left

holding

side,

System Board.

Board.

of

chassis.

to bottom

Board

out

SUPPLY DISASSEMBLY

four screws

Connector,

screws

four

remove board.

DISASSEMBLY

screws

remove

and

out of cabinet

ves

i

Remove

end

pull

and

Power

left

Supply. Remove

side

of

chassis

Disconnect Speaker

Remove

holding

SKI

Switch

holding

from bottom

bottom

plug- in

four screws

of chassis

Fan.

of

chassis

out

to

remove the end

and

and

board

of

top.

clear the tabs,

AC Connector.

of

cabinet.

and

and

plug

ho

I din

to AC

from

I

and

boards

Unplug

next

to chassis

Keyboard

Lift

of

?f

s
o

m

is,

=;

r-

<

X

SWITCHES

SYSTEM BOARD

VIDEO AND INTERRUPT

S2-1

S2-2 Vertical Sync

S2-3 Floppy Disk Controller

S2-4

Video

Parral

lei

RAM JUMPER

Remove

(U5 thru U8 and U13 thru U16.5

8047 MATH

Remove

IC

jumper from pins El

CO-PROCESSOR JUMPER

jumper from pins E3

(U33).

SWITCHES (S2)

Port

ON

Color

(Internal

CGA Board)

Enab ie Interrupt 5
Enab Ie

Enable Interrupt 7

and

E2 when

and E4 when

AND

Graphics Video

or

optional

I nterrupt

installing

installing

6

JUMPERS

OFF

Optional

Video Board

Disable Interrupt

Disab

Ie

Disable Interrupt

additonal 256K

on 8047

Math Co-Processor

Monochrome

Interrupt

RAM IC's.

5

6

7

PRELIMINARY

SERVICE

CHECKS

(Continued)

LOW.

NORMAL

HIGH, TURBO

J4

R26A

J1

RAM

RAM

BANK1

BANKO

VI

III

PRELIMINARY

ENVIRONMENT

SERVICE CHECKS

(Continued)

PREVENTATIVE MAINTENANCE

Computers perform best in a clean,

dust and smoke
as much as

around the Computer. Do

particles. Even though

commercial Computers

not block cabinet

power devices.

ELECTRICAL

Variations in the line

an AC

devices. A

may be

POWER

voltage can affect the

receptacle that is on a

power-surge protector,

needed to cure the

power line not used by appliances

problem. Do not switch

KEYBOARD

Liquids

Computer

disassemble the Keyboard and

water

cleaner and lint-free wipers

DISK DRIVES

Clean the read/write heads

Use

Handle

Drives can knock

old

spilled into the Keyboard

power plug from AC

and

it dry. Use

let

only an

disk in slot and close

approved head cleaning kit.

carefully

preserve

to

the disk head out

power outlet. Then, if

carefully rinse the

cotton swab to

a

on accessible

of the Disk Drives about

proper disk head alignment. A

door during transport.

cool area that is below 80

home Computers are not affected by

are affected, it is better to

power-line conditioner, or

can ruin it. Immediately

of alignment. If Disk Drive

vents of Computer,

Computer. Try to avoid these

non-interruptable power

power On and Off

after

circuitry or contacts are

Keyboard printed

clean between the keys. Use a

connectors and contacts.

once

month or

a

sudden bump or jolt to

degrees Fahrenheit and

cigarette

maintain a

Monitor, Printer,

or other heavy

spill occurs,

a

smoke-free area

fluctuations by using

current demand

frequently.

disconnect the

contaminated,

circuit board with

non-abrasive contact

must

after

transported,

be

hours usage.

100

free of

smoke

or other

supply

distilled

the Disk

place an

Store disks

handling precautions

in their protective covers

usually found on the back of disk

PRINTERS

Carefully vacuum

cleaner. Do not

blanket. This can cause

a

the Printer regularly. Wipe

oil the machine.

STATIC ELECTRICITY

Static electricity

anti-static

vironment.

discharge can affect

mats, sprays, tools

MONITOR

isolation transformer

Use an

some Monitors use a

the Monitor should never be

pattern is

preserve the

being changed

glare-reduction feature.

HOT chassis

and never touch the disk

surface areas clean using a

The oil will collect

components to

the Computer. In order to

overheat and fail.

abrasive grit and dust. The dust

and materials, and maintain good

with any Monitor that does

(chassis connected to one side

left on for long period of

periodically. Use

time

caution when cleaning

surface. Observe

protective covers.

minimize the

humidity in

not come

high brightness

at

part of the system

as

of the

anti-glare screens, to

light all-purpose

will act as

possibility,

the Computer en-

line). The

AC

level except when

the disk

use

since

face of

VII

r:-fc^ Pi

GH

"

:

SERVICE

"

BOOT UP

Disk

insert a boat*

and turn

le diskette Into

Computer. The

the

On

automatically boot up using

Disk Drive

Operating

A.

System)

puter will display

for a new

date and time.

If

MS-DOS (Microsoft

a

diskette is

the

date

the diskette

used, the

and time

After

Drive

Computer

and

the date and

time have been entered, the version

will

with

ning.

If Function Key

after the Computer beeps when turned On,

Computer will boot

in Drive B.

displayed on the Monitor screen

be
an A

which

indicates the

F3 is pressed immediately

up

from

diskette Inserted

a

DOS

is

MS-DOS

For
the

ENTER

list of file

a

current

key.

Disk Drive,

To specify Disk Drive that is not

current (default),

DIR B:

or

To return

and press

Disk Drive

for

MS-DOS

to

the ENTER

names on

DIR

type

DIR A:

use

8.

from Basic, type SYSTEM

key.

diskette fn

the

and press

for Disk Drive A

>ERATING

A

will

In

Disk

Com-

ask

DOS

of

along

run-

the

the

To load a

Disk Basic

program name enclosed

Enter Key.

To

enclosed

To run

and press the ENTER

press the CTRL and BREAK

the same

able

to prevent the user stopping the program while

RESETTING

CHECKS (Continued)

INS

',-UCTIONS

key or

load Disk Basic. To

type SYSTEM and press

view

To

diskette In the

press the ENTER key.

the

press

Drive B. Type

from Disk
fault)

save a program, type SAVE, the

or not recognize

is running.

it

BASICA

type

a list and the

current Drive, type

ENTER

key

FILES

Drive A If

drive.

program

from the

In quotes, and

program from

a

time. NOTE:

COMPUTER

and press the

return

the ENTER key.

names of

Type

to

list programs

*.*"

"A:

it

Is not the

in Disk Basic

diskette,

in quotes,

press

any Basic

key. To stop

(SCROLL

Some

CTRL and

the

RETURN key

DOS from Basic,

to

programs

FILES

FILES "Bs

from Disk

list

to

current (de-

or

LOAD, the

type

and press the

program name

ENTER key.

the

mode, type RUN

a program,

LOCK) keys at

programs will

BREAK

on a

and

*•*"

and

programs

Advanced

dis-

keys

to

To load
while

in DOS,

(System) program from a

a

the program name and

type

the ENTER key.

blank diskette must

A

can be used

memory. A formatted diskette

DOS

or a Start-up program before the Computer

wll I boot up using

Insert a diskette containing

gram" into

press

on the Monitor screen to

ted diskette.

will wipe out any

on the diskette. The Computer

the

defaults to Disk

Disk

Drive is not

ify the

to be

be

formatted or

ruined

to save information

that diskette.

Disk

ENTER

Drive A. Type

key. Follow

NOTE: Formatting a

programs

Drive A I f

specified. Be sure to spec-

destination Disk Drive

the original diskette may

by the default action.

formatted before

be

which Is

must contain

a "Format Pro-

the instructions

'format the unformat-

previously

automatically

the destination

of the diskette

BASIC

When turned On, the Computer will

MS-DOS

Drive A.
the

The manufacturer

diskette.

DOS.

gram

as long as the MS-DOS diskette

top of the screen.

The version

MS-DOS will

of

also supplies Disk Basic

To load Disk Basic,

Insert

on it. Type

a diskette with Disk Basic

BASIC and press

first boot up

diskette

press

FORMAT

and

diskette

placed

come

up

Is

appear at

pro-

the RETURN

Press the CTRL, ALT, and DEL keys, al

at the same time, to reset the Computer. The

Computer

can also be reset by

Reset button on lower left front panel.

It

CHANGING OPERATING

in

a

The

Video, Disk Drive, and

be changed
F4

immediately after the Computer beeps when

is

it

determine

-

F1

node.

Color

-

F2

Changes the Video mode

-

F3

by

turned On. Use the following chart to

the

Changes the Video mode

Graphics

Swaps Disk

MODES

CPU

pressing

Function Keys

speed

functionofeach Key:

(Computer normally comes up

to

mode.)

TV mode.

to

Drive

references.

becomes Drive B and Drive B becomes Drive

A. The Computer

Drive

top

-

F4

Changes

In
in

puter normal ly comes up with

of

7.16MHz.

(normally Drive

CPU

speed to

boot

will

B).

4.77MHz. The Com-

VOLUME CONTROL

on

Volume

A

Main

ternal

Control

System Board

(R26A)

to set the

is

speaker. The cabinet must

provided on the

volume

to gain access to the control.

three

I

pressing

modes

F1

Monochrome

Drive

from the

up

a CPU speed

the

of

removed

be

the

can

thru

In

A

In-

VII!

PRELIMINARY

SERVICE

CHECKS (Continued)

mk

CHASSIS

BOTTOM

VIEW

HEADS

SPINDLE

CHASSIS TOP VIEW

IX

5j*/M5

x

m

©

o

>-

<

UJ

Q

J_

o

s

COMPL'TERFACTS

SYSTEM BOARD,

KEYBOARD,

MODEL

POWER

TANDY

1000SX

SUPPLY

o

CO

o

C/>

5
o
m
o

SAFETY

Diagram.

Block

Disassembly

General Operating

GridTrace

Power Supply

System

Pinouts

IC

Line Definitions.....

LOgiC

Miscel laneous Adjustments.

Pa

r*T s list.........

Location Guide

Board

ChartS®

PRECAUTIONS

page 1

See

Instructions

Instructions...

Board

and Terminal Gu

a o a s ® e »

. . e .

.......

a

ides.

.30

,.21

th

th

Page

.

41

, 14

.

13

,

29

, 11

.9,40

.

34

ru 33

38

ru 27

INDEX

Photos

Keyboard

Power Supply

System Board 1

Safety

Schematics

Schematic Notes

Switches

Test

Troubleshooting

Precautions

Equipment

Board 28,35

thru

2

and Jumpers

8,

1

37,

2,

0,

42 thru

15 thru

Page

36

39

49
38

38

20

CO

o

1

S-

<

o

o

W
X

14

15

PJPw«

The listing of any available

constitute in any

Howard

by

such replacement part. The

compiled from information furnished to Howard W. Sams & Co.

by the manufacturers of the particular type of

listed.

Sams

W.

4300 West 62nd Street, P.O. Box

replacement

recommendation, warranty or guaranty

case a

& Co. as to

the quality and suitability of

numbers of these parts have been

87CS19008

Howard W. Sams

part herein does not

replacement part

DATE

9-87

Co.

4

Reproduction or

torial

assumed

© 1987

4300

U.S.A.

Indianapolis, Indiana 46206 U.S.A.

7092,

express permission, of

without

content,

with

Howard W.

62nd Street,

West

use,

in any manner,

respect to

is prohibited. No patent liability

of the information contained

the use

Sams

P.O. Box 7092,

Co.

&

editorial or pic-

herein.

Indianapolis, Indiana 46206

Printed in

U.S.

of America

is

TAKEN

WHILE PRESSING

SPACE BAR.

S.OV

50fis

—

ov

J4

X

S.OV

50fis

ov

1

J4

K

t

E

J4

CI

111

33pF^

C1131

33pF^

Y

2

B

J4

7

:

J

^

R

8

D

J4

C1151

33pFl

ciibI

33pF£

CIhI

33pFl

S

FBI

3

J4

.001

T

_L£J

J4

9

S.OV

00

NC

'part of

le

RP3|

10K

10K

f "*

10K

10K 10K

S

T4

10K?

IQtf

CU2i

33pF£

A

PHOTOFACT

STANDARD

NOTATION

SCHEMATIC

WTHgfflna

©

Howard

W. Sams

& Co.1987

TANDY

MODEL 1000SX

100

c

A PHOTOFACT STANDARD NOTATION SCHEMATIC

with

HEH3HH31

© Howard W. Sams & Co. 1987

46

MAC

A

e

IOD=

XMDO

XMD1

XMD2
XMD3
XMD4
XMD5
XMD6

XMD7

YMDO

YMD1

YMD2
YMD3
YMD4
YMD5
YMDS

YMD7

88 1OR

38

10W

MEMR

CS

cc

dt

AOO

AOI

A02

A03

A04

A05

AOS

A07

A08

AOS

AOIO

A011

AOI

2

AOI 3

A014

AOI

5

AOI

6

A017

A018

AOI 9

IODO

I

OD1

I0D2

I0D3

1004

IODS

IODE

I0D7

64

P

S3

P

62

P

61

P

60

P

59

P

SB

P

57

P

56

P

55

P

54

P.

53

P

52

P

SI

?

SO

p

49

P

48

P

47

P

46

P

73

P

72

P

71

P

70

P

6S

P

67

P

66

,83

,84

8040684

U30

©

RP9

33

33

-wv—

77

I

33

|

-=

—wv

J

-

I

5

33

6

|

I

- wv

=*-

43

RP8

33

33

-wv—

33

-WV—

33

-WV—

Si

MAO

MAI

HA2

MAS

MA4

MAS

MAS

MA7

R57

2200

NC

R53J

6.0V IQ

Kf

10)is

|

2

|

OV

S.OVOO

R59

1100

-wv

—

RS8

750

R62

3300

RSO

1200

R61

S80

!

—

W\

—

1.5V

lOfis

2N3904

Q3 VIDEO OUT

R65
270

I,

ns.ov

ci

_C58

£lB0pF

R64
620

,

,

—VA

CI

75

J

-

IOjiF'J'

0176^

.471

78L05A

VR1 RES

£

J10

\>

—

r>

c

C1771

1A

n

470pFj

U

:;R66

r

J10P

28

J10

->

s

2A

J10I

i—

AUDIO—

>

IB

T

Iff

1

JB

S.0VU3

^f

JB

20

33

-wv-

33

-wv-

—

, PART

OF

1

e

RP7

—

—

4l

RAS

CAS

tT

30

31

CA2

MEM

I

OS

MWEO

MWE1

VIDWAIT

mImw

V28MHZ

3

NC-

NC

PART OF

|

RP7

33

I

—wv-

2|

NC

33

-WV—

7

8^

NC

AOO

AOI

1000

1001

1002

1003

I0D4

10D5

1006

1007

NC

NC

38

P

16

PPINT

FDCDACK

PRINTCS

SYSRST

I

OR

IOW

FDCTC

DMATC

TC

27

H

1

H

23

H

31

H

28

H

23

P

30

L

22

P

24

L

25

£

20

if"

40

|1.5V

10fis

OV

8075068

U55

PARALLEL

PORT

ARRAY

10

H

18

IS

e

rpi2

33

12

33

A/W—

13

33

-wv—

14

33

-wv

—

15

33

-wv—

IS

33

-Wv—

10

33

-wv—

33

—wv—

CI64I

.0022±

cissl

.0022±

C166i

.00221

C155i

.0022^

C162J;

.00225

C1B3J-

.00221

C156i

.0022^

9

5j

C167-1

.

.00221

E5 E6

RP1

1 4,™

4700

??

700

4700

4

4700

3

H2 T7

[8

"•

i

I

4700$4700?4700

3

I

m

5.0V00

•

PPDATAO

•

PPDATA1

PPDATA2

•

•

PPDATA3

•

•

PPDATA4

PPDATA5

-

PPDATA6

-

PPDATA7

-

C154i

33pF*

CI

S\X

33pFl

PPACK

PPBUSY-

PPPAEM-

R51<

470K?

CI

53!

33

P

FJ

C1591

33pFJ

C1521

33pFJ

C16oi

33pF$

C16B1

33pFl

PFAULT

PPINIT

PPAUTOF

PSEL

PPSTROB

NC-

J7

3

J7

S

J?

->

7

-J

9

J7

11

J7

->

13

J7

15

J7

17

J7

19

J7

21

J7

4

23

J7

26
J7

30
J?

->

27
J7

25

J7

1

J7

29

PHOTO

CIRCUITRACE

=

SCHEMATIC

CIRCUITRACE

=

CABLING.

TUBE

LINES REDUCE

USE

OF MULTIPLE

LINES

11

=

A

=>D

=100

J7

2

J7

<r

4

J?

<-

6

J7

3

J7

<

10

J7

<

12

J7

<-NC

14

J7

16

J7

18

J7

<^

20

J7

22

J7

24

J7

<— NC

26

J7

<

31

J7

<-

33

J7

<— NC

32
J7

<

34

o

m

&,

r-

S

O

<

o

CO

X

1

R52

4700

1

m

S.0VCA3

A

PHOTOFACT STANDARD

NOTATION

SCHEMATIC

with

EEBHH3B31

©

Howard W. Sams

& Co. 1987

>CA

=CB

=CC

45

3

A

C074HCT02E

PART

0FUS3

RHOTO CIRCUITRACE

=

SCHEMATIC CIRCUITRACE

=

CABLING.

TUBE

LINES REDUCE

USE

OF MULTIPLE

LINES

A PHOTOFACT STANDARD NOTATION SCHEMATIC

w,th

HEHSEHH

© Howard W. Sams

&

Co. 1987

44

I/O CONNECTORS

e

i

< —

.J

m

rpi3

TQK

10K

-WV—

10K

*/w

TOK

^w—

TOK

10K

I

OK

10K

10K

<A29

<{a27

<*A25

<|A24

(A21

<JA20

>.!9

AT

AT 7

ATS

>T5

AT

>13

>T2

A6

I

B2s

BT7

bis

a

4

JT

T, JT2

I

AOO ^A3T

AOT <|a30

A02

A03 <[a28

A04

AOS (A26

A06

A07

A08 <A23

A09 ^A22

ATO

AIT

-A12

-AT

3

-AT 4

-ATS

-ATS

-AT 7

-AT

8

-AT 9

•DO-

•DT

•02-

•

03-

D4-

•D5-

•06-

U

i

I

•

FDCDACK

•NC

•

10

RYDIN

mm

foi

low

memr

—

—

NC

—

—

—

—

-ft

07

DACK3 CBT5

__

-FDCDACK-

-

TJAClcT

REFRESH

<fA9

CAB

-^A7

<f

"I"

<A4

("A3

<JA2

.

I

J13

I

B29>

JT4

|JT5B24V

I-

-

DRQT

-FDCMRQ-

-DRQ3-

T38"-

—

-mEmR-

-mERB-

B30>

B27>-

|

I B20>-

I J

NC

•NC

J

R47

:

R45

2200

R49;

2200'

2200

-<

t

t

OSC
ALE

DMATC

e=

CA

<=

CB

<=

CC

A PHOTOFACT

Howard

©

W.

STANDARD

WiTH

BEBBBBi

Sams

& Co. 1987

NOTATION

SCHEMATIC

P1

J1

380 aA

AC

POLARIZED

*=

Ofra

2SA1441

[7]

Q412V RE6

"~

r

"

MAKEN FOM COMMON TIE POINT

^

PHOTO

CI

RCU]

TRACE

=

SCHEMATIC

CI ROM

TRACE

=

Oj]

COMPUTER

o

c/>

o

(/>

CO

o

m

^

i-

5

o

<

o

CO

X

>

TO

COMPUTER

POWER

SUPPLY

42

A PHOTOFACT

STANDARD NOTATION

SCHEMATIC

©

Howard W. Sams & Co.

1987

POWER

SUPPLY

7

M74LS04P

PART

0FH2

T

C

M
P

u

T
E

R

KEYBOARD

8

HI

5.ovan

SCHEMATIC CIRCUITRACE

A PHOTOFACT STANDARD NOTATION SCHEMATIC

WITH

HESffiEEBl

Howard W. Sams

©

Co. 1987

&

PHOTO

s.ovan

CIRCUITRACE

m

=

=

QT]

IC

PINOUTS &

TERMINAL GUIDES

SN74LS245N

P8068-2

9

10

D1R

W

*cc

d_

J-i G

A1

rv^—4

J

ENABLE

Bl

A2

B2

A3

B3

A4

B4

A5

BS

AS

BS

A7

B7

A8

B8

GN0

^J

U39,U40,U52
TRANSCEIVER

TOP VIEW

(

SN74LS373N

OUTPUT CONTROL

. w

V|

2IDs

OE

o e

a

OE

G

80

3

y

f

v

A

\

r

A

4

20

U

*0E

Q

7Q

S

f

s

3D

30

OE

D

8

a

OE

8

BO

7

\

v

f

¥

f>

K

A

-VI

B

48

"

*8E

a

aE*

°

a

sa

9

<•

\

GrID

^1

ENABL

e e

^1

20

19

IB

17

IB

15

14

13

12

11

U42.U43

LATCH

TOP VIEW

etc VCC

AM

A1S

A13 A1B/53

A12

A17/S4

All

A1B/SS

A10 A19/5B

A9

SSO

AS

NN/HX

AD7

TO

AD6

HOLD

ADS

AD4

NLDA

WR

AD3

io/h

AD2

DVR

AD1 DEN

ADO

ALE

NH1 "iNTA

INTO TEST

CLK

READY

6ND

RESET

(MAX

HUE)

40

39

38

37

3B
35

34

33

32

8087

D8253C-5

C074HCT138E

31

CRO/STO)

30

CR0/ST1)

29

(LOCO

28

CSZ>

27

ran

28 ran
25 caso)

24 casn

23

22

21

U36

CPU

TOP VIEW

P8259A

\J

cs VCC

WR

AO

TO Tnta

D7

IR7

06

1RB

05

1R5

04

IR4

03 IR3

D2

IR2

D1

IR1

DO

1R0

CAS INT

CAS

1 spTen

6N0 CA5

2

U44

INTERRUPT

CONTROLLER

TOP VIEW

SND

VCC

AD14 AD15

AD13

A16/S3

AD12

A17/S4

AD11 A18/SS

AD10 A19/SB

ADS
AD8

aS/s?

Ra/6T1

AD7 INT
AD6

RQ/GTD

AD5

NC

AD4

NC

ADS S2

AD2

si

A01 so

ADO oso

NC

0S1

NC

BUSY

CLK

READY

SND

RESET

KEYBOARD

POWER SUPPLY

\S

1

07 VCC

2 D6

RW

3 05

TO

4

D4 CS

5 03 A1

8 02 AO

7 01

CLK

a DO

0UT2

9 CUM

6ATE2

10

OUTO

CLK1

11

8ATE0 BATE1

12

GND 0UT1

U33

COPROCESSOR

TOP

VIEW

U23

TIMER

TOP

VIEW

HC14529B

STRBX

VCC

XO

STRBY

XI YO

X2 Y1

X3 Y2

A

Y3

B V

GND

Z

U25
INTERFACE
TOP

VIEW

SELECT -<

ENABLE

-<

A

V-—

'

VCC

b-

Y0B

1

C

Y1

62A

Y2

S2B

Y3

81

Y4

Y7

>—

YS

6N0

Y6

V

U19

DECODER

TOP

VIEW

U21,U54,USB,US7

BUFFER

TOP VIEW

DB048C

TO VCC

XTAL 1 T1
XTAL 2

P27

RESET

P2S

SS P25

INT

P24

EA

PI7

TO PI

6

WEN PI 5

WR

PI

4

ALE P13
DBO

PI

2

DB1

P11

DB2 P10
DBS VDD

DB4

PR06

0B5

P23
DBS P22
DB7

P21

SND P20

IC

2C

3C

4C

5

B

7E

314

313

312

311

310

3

9

3 8

6

1

'

°

'

I

DENT

IC

2C

3C

3

8

3

5

3

4

*

IC3

BOTTOM

VIEW

on

I

60

IC2

FRONT VIEW

PHC2

TOP VIEW

M2

TOP

VIEW

E C B

^3

Q2.Q3

BOTTOM VIEW

in

!C

3

4

33

O

I

DENT

PHC1

TOP VIEW

BCE

04

FRONT

VIEW

M1

KEYBOARD

CONTROLLER

TOP VIEW

—

<i

o

u u

u

BCE

Q1

FRONT VIEW

KM412S6-15

AB

"*

SND

D IN
WE

CAS

D

OUT

RAS AB

AO A3

A2 A4

A1

A5

VCC

A7

U1

THRU

U16

RAM

TOP

VIEW

ic

2C
3C

AC

sc

sc
7C
BC
BC

IOC

11C
12C

13C

14C

328
327
326

325
324

323

322

321

320
319
318
317

316
315

IC
2C
3C

(C
SC
SC

7C
BC

31S

315

314

313
312

311

310

39

U37A.U50

TOP

VIEW

U41

TOP VIEW

6 I

VR1

BOTTOM

VIEW

ic

2C

3C

4C

5C

BC

7C
BC
9C

318
317
316
315

314

313

312

311

310

IC

2C
3C
4C

SET

6C

7C

ac

sc

10C

11C

12C
13C

14C
15C

16C

17C

18C
19C

20

C

340
339
338
337
336

335

334

333

332

331

330

329
328
327
326
325

324
323
322

321

IC

320

2C

319

3C 318
4C

317

513

316

Sti

315

7C 314

Bq

313

9C

ai2

on

tin

IC

2C
3C
4C

5C

6C
7C

14

13

312

311

310

3

9

3

8

U18

TOP VIEW

U22,U37,U51,U55

TOP

VIEW

IC

3C

3C

4

3

B

3

7

3 6

S

U24,U31,U34,U35

TOP VIEW

U26.U27.U38.

TOP VIEW

U17,U20,U2B,

U45

THRU

U49,

U53

TOP

VIEW

E B C

Q1.Q3

BOTTOM VIEW

o

C/>

o

CO

o

m

^

"z

o

<

o

CO

X

40

SYSTEM

BOARD

10

3

#

-4**s

.

-

.

:

i^ii'W'iii

afer'li

•'s'R

S: ^ii-

IN?;;

ft

I

I

mm mm

s"&

3*&

j^ci

*"i-

*

A

4 5 6

|

7

J

8

J

9

10

t

11

;

12

J

13

14 15

J

16]17

{

18J19

—

•!

!

MM

S*«.«fci

sis

:<»!»;,:

£U ,€.

.1

<t£ j t.

C)

•-

i>

ft.,

•:

«4£

*i

* **

*

iillll

20 I

21 22

23

A Howard

W.

Sams

EMESSB

Photo

o

o

<

o

c/>

X

SYSTEM BOARD

39

SYSTEM

BOARD

GridTrace LOCATION

GUIDE

C1

C2

C3

C4
C5

C6

C7
C8

C9
CIO

C11

CI 2

C13

C14

C15

C16

C18

C19

C21

C22

C23

C25

C26

C28
C29

C29A

C30

C30A

C31

C32

C34

C35

C37

C37A

C39
C40

C41

C42

C43

C44

C45
C47
C48
C50

C51

C52

C53

C54

C55

C56

C57

C58

C97*

C98*

C99

C100

C101

C102

CI 03

C104

C105
C106

07

CI

C108

CI

09

C110

cm

12

C1

CI 1

14

C1

C115

16

C1
C1

17

C1 18

19

B-1

B-6

B-7

B-8

B-9

B-10

8-1
B-1

D-5

D-6

D-7

D-8

0-9

D-10

D-1!

D-12
E-9
E-12

E-17

E-21

F-22

G-3

G-4

F-6

G-7

1-9

H-12

1-15

H-15

H-17

1-15

1-17

K-5

J -3

J-9

K-9

L-16

K-18

K-20

K-23

L-2

L-5

M-2

M-5

M-7

M-15

0-5

N-15

P-4

P-9

Q-8

Q-11

K-2

M-10

N-11

B-2

A-14

C-17

C-17

C-18
C-18

C-19

C-19

C-19

C-20

A-22

C-21

3

C-21

C-21

C-22
C-22
C-22

B-20

C-15

C1

20

CI

C121

22

CI

C123

24

CI

C125

1

CI 26

C127

C128
C129

C130

C131

CI 32

CI

33

C134

CI 35

C136

C137

C138

C139

C140

C141

C142

CI 43

C144

CHS

46

CI
CI 47
CI 48
CI 49

C150

C151

C152

C153

C154
C155
C156

C157

C157A

C158

C159

C160

C161

C162

63

CI

C164

C165

C166

C167

C168

C169

C170

C171

72

CI

C173
C174
C175

C176

C177

C178

C179

C180

C181

C206

C222

C242
C243
C244

C249

C251

C264

C265

CMC1

D-22

F-1 CR2

F-2 FBI

F-3 FB2
G-3 FB13

CR1

G-4 FB16

F-1 3 FB38

1-2

H-3

F-5

H-3

FB39
FB40

FB41

FB42

C-4 J1

H-19

1-19

J-6

L-11

K-11

K-16

M-7 J8

M-16

M-18

M-20

M-2
P-5

P-9

P-9
P-9

P-10
P-10

P-10

P-11

P-11
P-11

Q-2

0-2

0-3

0-5

0-5

R-7

R-7
0-8
0-2

0-2

0-3

0-4

0-4

Q-4

0-4

0-4

0-5

0-6

J2

J3
J4

J5

J6

J7

J9

J10

J11

2

J12

J13

J14

J15

01

02
03

R1

R2
R3
R4
R6

R7
R8

R9

R10

R11

R12

R13

R14
R15

R16
R17
R18

R19

R20

R21

R22

R23

R-8 R24
R-8

R25

R-9 R26

R-9 R26A

R-9

R-10

R-13

R-14

R-14

S-17 R32
S-17 R33

S-17 R34

S-20

B-1

F-2 R37
L-3

M-1 R39

M-4

R27

R28

R29

R30

R31

R35

R36

R38

R40

N-13 R41

M-2 2 R42

P-13 R43

P-14

R44

R-13 R45

D-1

M-1

B-1 4

B-16

C-20

C-21

R-10
R-10
R-10

R-11

0-13
A-14

A-16

A-18

A-20

N-5

N-11

S-4

S-7

S-10

S-12

R-16

R-17

R-19

R-21

R-23

C-16

D-1

R-14

B-1
B-1 4

C-18

C-18

D-1

D-1 4

D-1
D-1 4

D-1

D-1

D-1

D-1
D-1
D-1

D-20

E-11

F-4

F-4

G-8

G-20

F-22

G-22

G-22

G-6

G-10

F-10

H-2

H-2

H-2

1-2

F-5

H-4

J-10

J-21

J-22

L-7

K-12

M-1 1

N-4

N-6

N-9

N-11

N-11

N-12

N-14

R46

R47

R48

R49
R50

R51

R52

R53

R54

R55

R56

R57

R58

R59

R60

R61

R62

R63
R64

R65

R66

R67

R99

RP1

RP2

RP3

RP4

RP5

RP6

RP7

RP8

RP9

RP10

RP11

RP12

RP13

SI

S2

111

U2

U3

U4

U9

U10

U11

U12

U17
U18

U19
U20

U21

U22

U23

U24
U25
U26
U27

U28
U29

U30

U31

U34

U35

U36
U37
U38
U39

U40

U41

U42

U43

U44

U45
U46

N-15

N-16

0-14

0-14

P-6

0-2

o-i

R-7

R-10
R-10

R-10

R-11

R-11

R-11

R-11

R-11

R-11

R-11

R-12

0-13

R-14

R-15

M-3

C-16

C-16

D-21

H-5

1-5

1-5

H-17

1-16

J-16

M-1

0-3

P-6

P-22

A-21

J -20

A-5

A-6

A-7

A-8

C-5

C-6
C-7

C-8

C-14

E-9

E-11

E-13

E-15

E-17

E-21

H-17

6-1

G-3

G-4

G-5

H-8

H-14

H-15

1-15
1-17

1-19

K-1

K-5

K-7

L-7'

L-13

L-16

L-18

L-20

L-1

L-2

U47

U48

U49

U50

U51

U52

U53

U54

U55

U56

U57

VR1

VR2

Y1

Y2

*

Located

bottom

of

L-4

M-1

M-2

M-4
M-8

M-1 3

0-4

N-13

P-1

P-7

P-9

0-14

S-15

K-10

N-7

on

board.

o

o

CO

CO

2
O
O

m>
o°

o

o

w
X

_,

<

11

5.0V(B)

U10

U11

U53

U51

U56

12.0V(A)

-12.0V

5.0V{A)

SOURCE

SOURCE

SOURCE

NOTE;

ARROWS

ON IC'S

INDICATE

PIN

1

UNLESS

NOTED

2

3

B

C

E

V

R2

mm

VR1

Q3

-5.0V

SOURCE

o

o

"<

SYSTEM

BOARD

12

A

Howard W. Sams

MI:MIIH:MJS

Photo

SYSTEM

BOARD

37