Texas instruments Sams ti-99/4a phc004a User manual

TECHNICAL

SERVICE

DATA

FOR

YOUR

COMPUTER

COMPUTERFACTS

COMPUTER

:

TEXAS

INSTRUMENTS

TI-99/4A"

Model

PHC004A

CC2

If

seal

is

broken,

nonreturnable.

TI-99/4A

Model

PHC004A

SAMS

COMPUTERFACTS™

put

easy

to

use,

informative

technical

ata

right

at

your

fingertips.

Each

e ition

inclu es

specific

service

information

on

the

in ivi ual

component,

along

with

some

overall

troubleshooting

hints.

The

following

information

is

just

a

sample

of

the

many

valuable

time

saving

features

containe

in

this

exclusive

Sams

COMPUTERFACTS

publication:

•

Preliminary

Service

Checks

section

is

an

easy

to

use,

step

by

step

gui e

for

the

experience

technician

or

hobbyist,

an

even

beginners.

•

SAMS

famous

in ustry

accepte

stan ar ize

notation

schematics

containing

C

ircui

T

race

,®

G

rid

T

race

,™

waveforms,

voltages

an

stage

i entification.

•

Ste

p

by

Step

Troubleshootin

g

gui es

the

technician

through

the

necessary

proce ures

to

quickly

locate

the

problem.

TROUBLESHOOTING

MICROPROCESSOR

CHIP

(CPU)

OPERATION

Verify

the

processor

is

functioning

by

checking

the

signals

on

the

a ress

lines

(pins

10

thru

24

of

IC

U600)

an

the

ata

lines

(pins

41

thru

56)

using

a

logic

probe

or

a

scope.

If

a

logic

probe

is

use ,

refer

lo

the

"Logic

Chart"

for

the

correct

rea ings.

If

a

scope

is

use ,

the

waveforms

on

the

a ress

lines

(except

pins

22

an

23

which

have

no

signal

in

Power

Up

mo e)

shoul

be

similar

to

Figure

1.

The

waveforms

on

the

ata

lines

shoul

be

similar

to

Figure

2.

•

Quick

Component

Location

using

the

SAMS

exclusive

G

rid

T

race

,

C

ircui

T

race

,

an

component

photographs.

E5SD

iflCZV'

4

5

6

7

8

9

10

11

12

•

Log

ic

Chart

containing

logic

probe

rea ings

to

isolate

efective

circuitry

an

components.

LOGIC

NO.

IC

U100

NO.

IC

U100

NO.

IC

U102

IC

U103

IC

U104

IC

U105

IC

U106

IC

U107

IC

U108

IC

U109

1

p

21

p

1

L L

LL L

L

LL

2

p

22

p

2

P P

P

3

p

23

p

3

H

HH

H

•

Complete

Components

Parts

List

in

an

easy

to

use

format

with

fiel

replacements

shown

when

possible.

SAMS

unique

semicon uctor,

chip

an

IC

cross-reference

gives

you

many

replacements

to

choose

from

an

is

available

at

your

Electronic

Distributor.

SEMICONDUCTORS

(Select

replacement

for

best

results)

ITEM

NO.

TYPE

No.

MFGR

PART

No.

REPLACEMENT

DATA

ECG

PART

No

GENERAL

ELECTRIC

PART

NO.

MOTOROLA

PART

No.

NTE

PART

NO.

RCA

PART

NO.

WORKMAN

PART

No. ZENITH

PART

No.

0102

1SS53

1149-2576

ECG519

GE-514

1N4935

NTE

519

SK

9091/177

WEP

925/519

103-131

0103

1N60FM

1149-2527

ECG

109

1N60

NTE

109

SKJ088

WEP

134/109

I03-Z9001

0201

1N4004GP

1201-4205

ECG1

16

GE-504A

1

N4004

NTE

1

16

SK3312

WEP157

212-76-02

D501

thru

D5O3

1SS53

1149-2576

ECG519

GE-514

1N4935

NTE519

SK9091/177

WEP925/519

103-131

C

ircui

T

race

is

a

registere

tra emark

of

Howar

W.

Sams

&

Co.,

Inc.

COMPUTERFACTS

an

G

rid

T

race

are

tra emarks

of

Howar

W.

Sams

&

Co.,

Inc.

TI-99/4A

is

a

tra emark

of

Texas

Instruments,

Inc.

To

or er,

see

your

Sams

Representative,

or

telephone

800-428-SAMS.

SAMS

Howar

W.

Sams

&

Co.

A

Division

of

Macmillan,

Inc.

4300

West

62n

Street,

In ianapolis,

In iana

46268

CC2

08901

ISBN:

0-672-08901-7

TEXAS

INSTRUMENTS

TI-99/4A

MODEL

PHC004A

SAMS-

COMPUTERFACTS^

PRELIMINARY

SERVICE

CHECKS

TEXAS

INSTRUMENTS

CC

2

TI-99/4A

MODEL

PHC004A

This

ata

provi es

the

user

with

a

time-saving

service

tool

which

is

esigne

for

quick

isolation

an

repair

of

computer

malfunctions.

Check

all

interconnecting

cables

for

goo

connection

an

correct

hook-up

before

making

service

checks.

Disconnect

all

peripherals

except

the

monitor

from

the

com



puter

to

eliminate

possible

external

malfunctions.

Replacement

or

repair

of

the

power

supply

boar ,

RF

mo ulator,

keyboar ,

or

connectors

may

be

necessary

after

the

malfunction

has

been

isolate .

GENERAL

OPERATING

INSTRUCTIONS

POWER

UP

When

the

computer

is

turne

On,

the

main

title

screen

will

be

isplaye

on

the

monitor.

Press

any

key

an

a

menu

will

be

isplaye .

The

menu

choices

will

be

etermine

by

the

Soli

State

Cartri ge

use .

Turn

the

computer

Off

when

in



serting

or

removing

a

Soli

State

Cartri ge.

Refer

to

the

menu

an

press

the

key

for

the

esire

function.

For

instructions

to

loa

an

save

programs

on

cassette

tape,

refer

to

"Cassette

Operation".

Run

a

basic

program

by

typing

RUN

an

press

the

ENTER

key.

Stop

a

program

by

hol ing

own

the

FCTN

key

an

press

the

number

4

key.

The

computer

will

return

to

the

basic

mo e

an

the

program

will

be

unaffecte .

Reset

the

computer

by

hol ing

own

the

FCTN

key

an

press

the

=

key.

The

computer

will

return

to

the

main

title

screen

an

any

program

in

memory

will

be

lost.

CASSETTE

OPERATION

Connect

the

cassette

cable

to

the

cassette

plug

on

the

rear

of

the

computer.

Connect

the

plug

with

the

re

wire

to

the

Mic

input

on

the

recor er,

the

plug

with

the

white

wire

to

the

Earphone

output

on

the

recor er

an

the

plug

with

the

black

wire

to

the

Remote

input

on

the

recor er.

NOTE:

The

remote

control

may

not

work

on

some

recor ers.

Set

the

Tone

control

on

the

recor er

to

Maximum

an

the

volume

control

to

mi -range.

Verify

the

ALPHA

LOCK

key,

on

the

computer,

is

in

the

own

position

an

put

the

computer

in

BASIC

mo e.

Save

a

program

by

typing

SAVE

CS1,

press

the

ENTER

key

an

follow

the

instructions

that

appear

on

the

monitor

screen.

Loa

a

program

by

typing

OLD

CS1,

press

the

ENTER

key

an

follow

the

instructions

that

appear

on

the

monitor

screen.

If

a

program

will

not

loa ,

set

the

Volume

control

to

a

ifferent

level

an

try

loa ing

the

program

again.

When

using

two

recor ers,

the

recor er

connecte

to

the

three

plug

section

of

the

cable

will

be

CS1

an

the

recor er

con



necte

to

the

two

plug

section

will

be

CS2.

CS2

can

be

use

for

saving

programs

or

ata

only.

Save

a

program

on

CS2

by

typing

SAVE

CS2,

press

the

ENTER

key

an

follow

the

instructions

that

appear

on

the

monitor.

TEXAS

INSTRUMENTS

CAAA

C

Howar

W.

Sams

&

Co.,

Inc.

4300

West

62n

Street,

P.O.

Box

7092,

In ianapolis,

In iana

46206

U.S.A.

The

listing

of

any

available

replacement

part

herein

oes

not

constitute

in

any

case

a

recommen ation,

warranty

or

guaranty

by

Howar

W.

Sams

&

Co.,

Inc.,

as

to

the

quality

an

suitability

of

such

replacement

part.

The

numbers

of

these

parts

have

been

compile

from

information

furnishe

to

Howar

W.

Sams

&

Co.,

Inc.,

by

the

manufacturers

of

the

particular

type

of

replacement

part

liste .

Repro uction

or

use,

without

express

permission,

of

e itorial

or

pictorial

content,

in

any

manner,

is

prohibite .

No

patent

liability

is

assume

with

respect

to

the

use

of

the

information

containe

herein.

©

1984

Howar

W.

Sams

&

Co.,

Inc.

4300

West

62n

Street,

P.O.

Box

7092,

In ianapolis,

In iana

46206

U.S.A.

Printe

in

U.S.

of

America.

84CF14905

DATE

4-84

COMPUTERFACTS-OF-THE-MONTH

SET

NO.

CF1

FOLDER

CC

2

PRELIMINARY

SERVICE

CHECKS

(Continue )

SERVICE

CHECKS

SEE

INTERCONNECTING

DIAGRAM,

PLACEMENT

CHART,

AND

PHOTOS

TO

MATCH

THE

NUMBER

IN

THE

CIRCLES

WITH

THOSE

IN

THE

FOLLOWING

DATA

FOR

SERVICE

CHECKS

TO

BE

PERFORMED.

(T)

RF

MODULATOR

(a)

Power

computer

an

verify

the

power

in icator

LED

is

lit.

NOTE:

If

the

power

in icator

LED

is

not

lit,

refer

to

the

"Power

Supply

Check"

section.

(b)

Verify

the

channel

select

switch

is

on

the

same

channel

as

the

monitor,

channel

3

or

4.

(c)

Verify

the

TV/mo ulator

switch

is

in

mo ulator

position.

( )

Check

for

ba

connections

an

improper

hook-up

at

the

monitor

an

at

the

computer.

(e)

If

the

computer

still

oes

not

come

up

when

powere ,

check

the

RF

Mo ulator

by

substitution.

(2)

POWER

SUPPLY

(a)

Power

computer

an

measure

the

AC

voltages,

from

the

secon ary

of

the

Power

Transformer

(T

1),

on

the

power

supply

boar .

If

there

is

no

AC

voltage,

replace

AC

a aptor.

(b)

Disconnect

P2

from

power

supply

boar .

Measure

the

DC

voltages

at

P2.

(c)

Measure

the

Regulator

B

+

voltage

(21.5V)

at

L6.

If

the

voltages

are

not

present

or

are

incorrect,

replace

or

repair

the

power

supply

boar .

(3)

MAIN

BOARD

@

(a)

Computer

oes

not

come

up

when

powere .

Check

for

-5.15V

at

1,

5.14V

at

pins

2,

33,

59

an

64,

an

11.84V

at

27

of

the

Microprocessor

IC

U600.

Verify

the

Timing

Generator

is

function



ing,

by

checking

for

pulses

on

pins

8,

9,

25,

an

28

of

the

Microprocessor

IC

U600

using

a

logic

probe.

(b)

No

soun ,

substitute

the

Soun

Generator

IC

U511.

(c)

Vi eo

problems,

substitute

the

Color

Graphics

Vi eo

Display

IC

U100.

( )

Monitor

remains

blank

when

the

computer

is

turn



e

On.

Substitute

a

monitor

known

to

be

goo .

Substitute

GROM

IC

U500

an

Vi eo

IC

U100.

(e)

Monitor

isplays

insert

cartri ge

after

pressing

the

number

1

key.

Substitute

GROM

IC

U501.

(f)

If

there

is

no

line

fee

when

pressing

the

ENTER

key,

substitute

GROM

IC

U502.

(g)

Remote

control

line

will

not

turn

on

CS1.

Remove

power

to

computer

an

check

the

resistance

from

the

emitter

to

collector

of

Q401.

The

resistance

shoul

rea

low

uring

the

time

the

recor er

is

suppose

to

be

running

an

open

when

not

running.

If

these

rea ings

are

correct

check

the

cassette

recor er.

(h)

Check

the

resistance

rea ing

from

the

emitter

to

collector

of

Q403

if

CS2

will

not

turn

On.

(i)

Keyboar

fails

to

function.

Disconnect

the

keyboar

connector

P100.

Power

computer

an

check

the

voltage

an

logic

rea ings

at

J100.

If

the

rea ings

are

correct,

check

the

keyboar .

KEYBOARD

Substitute

the

keyboar

or

locate

the

ba

key

an

clean

the

key

switch

with

switch

cleaner.

TEST

EQUIPMENT

AND

TOOLS

REPLACEMENT

PARTS

AC

A aptor

Mo el

AC9500

TEST

EQUIPMENT

Digital

Volt/Ohm

Meter

Logic

Probe

IC

TYPE

NO.

TOOLS

U100

TMS9918A

Phillips

Screw river

U500

CD2155NL

Small

Screw river

U501

CD2156NL

Sol ering

Iron

U502

CD2157NL

Switch

Cleaner

U511

SN94624N

PRELIMINARY

SERVICE

CHECKS

(Continue )

RF

MODULATOR

CASSETTE

INTERCONNECTING

DIAGRAM

TEXAS

INSTRUMENTS

COMPUTERFACTSOFTHEMONTH

SET

NO.

CF1

FOLDER

CC

2

III

PRELIMINARY

SERVICE

CHECKS

(Continue )

PRELIMINARY

SERVICE

CHECKS

(Continue )

MAIN

BOARD

IV

TEXAS

INSTRUMENTS

TI-99/4A

MODEL

PHC004A

MAIN

BOARD

V

PRELIMINARY

SERVICE

CHECKS

(Continue )

DISASSEMBLY

INSTRUCTIONS

CABINET

BOTTOM

REMOVAL

Remove

the

On-Off

knob.

Remove

Phillips

screws

1

thru

7

(See

Figure

1)

from

the

bottom

an

remove

the

cabinet

bot



tom.

POWER

SUPPLY

BOARD

REMOVAL

Remove

Phillips

screws

7

an

8

(See

Figure

2)

from

the

power

supply

boar .

Lift

the

boar

up,

unplug

the

cable

going

to

the

main

boar

an

remove

the

power

supply

boar .

MAIN

BOARD

REMOVAL

Remove

Phillips

screws

1,

2

an

3

(See

Figure

2)

hol ing

the

main

boar .

Lift

up

the

main

boar ,

unplug

the

keyboar

an

remove

the

main

boar .

To

remove

the

shiel ,

remove

the

two

metal

clamps

(See

Figure

2)

an

unplug

the

cartri ge

plug.

Remove

Phillips

screws

an

nuts

4,

5

an

6

(See

Figure

2)

an

remove

the

top

an

bottom

shiel .

KEYBOARD

REMOVAL

Remove

Phillips

screws

9

thru

12

(See

Figure

2)

hol ing

the

keyboar .

Unplug

the

keyboar

from

the

main

boar

an

remove

the

keyboar .

Figure

2

BOTTOM

VIEW

TEXAS

INSTRUMENTS

TI-99/4A

MODEL

PHC004A

VII

PRELIMINARY

SERVICE

CHECKS

(Continue )

COLOR

PLACEMENT

CHART

VI

PRELIMINARY

SERVICE

CHECKS

(Continue )

POWER

SUPPLY

BOARD

VIII

TEXAS

INSTRUMENTS

TI-99/4A

MODEL

PHC004A

COMPUTERFACTS^

TEXAS

INSTRUMENTS

2

TI-99/4A

MODEL

PHC004A

bO

TI-99/4A

MODEL

PHC004A

PRELIMINARY

SERVICE

CHECKS

SAFETY

PRECAUTIONS

ENCLOSED

See

page

13.

>

INDEX

Page

A justment

.............................................................

15

Block

Diagram

.......................................................

25

Disassembly

Instructions

.....................................

12

General

Operating

Instructions

...........................

12

Gri Trace

Location

Gui e

Power

Supply

Boar

.......................................

5,32

Line

Definitions

.....................................................

13

Logic

Chart

...................................................

22,23,24

Parts

List

...................................................

16

thru

21

Photos

Keyboar

.........................................................

4,33

Photos

(Continue )

Page

Main

Boar

.............................

6

thru

10,27

thru

31

Power

Supply

Boar

.......................................

5,32

Safety

Precautions

...............................................

13

Schematics

IC

Pinouts

&

Terminal

Gui es

.....................

11,26

Keyboar

.............................................................

2

Main

Boar

.........................................

2,3,35,36,37

Notes

.................................................................

11

Power

Supply

.....................................................

34

Troubleshooting

...............................................

14,15

CAAfiC

Howar

W.

Sams

&

Co.,

Inc.

w

WF

v

I

wtm

4300

West

62n

Street,

P.O.

Box

7092,

In ianapolis,

In iana

46206

U.S.A.

The

listing

of

any

available

replacement

part

herein

oes

not

constitute

in

any

case

a

recommen ation,

warranty

or

guaranty

by

Howar

W.

Sams

&

Co.

,

Inc.

,

as

to

the

quality

an

suitability

of

such

replacement

part.

The

numbers

of

these

parts

have

been

compile

from

information

furnishe

to

Howar

W.

Sams

&

Co.,

Inc.,

by

the

manufacturers

of

the

particular

type

of

replacement

part

liste .

Repro uction

or

use,

without

express

permission,

of

e itorial

or

pictorial

content,

in

any

manner,

is

prohibite .

No

patent

liability

is

assume

with

respect

to

the

use

of

the

information

containe

herein.

©

1984

Howar

W.

Sams

&

Co.,

Inc.

4300

West

62n

Street,

P.O.

Box

7092,

In ianapolis,

In iana

46206

U.S.A.

Printe

in

U.S.

of

America.

84CF14905

DATE

4-84

COMPUTERFACTSOF-THE-MONTH

SET

NO.

CF1

FOLDER

CC

2

SI

S2

S3

S4 S5

S48 S45

WAVEFORM

TAKEN

WHILE

PRESSING

THE

2

KEY

J

I

??

Pl:

?!:

JI

S32

JI

R334

470

R332

470

R338

470

ALPHA

piling

LOCK

.001

R337

470

J?

/JA

L

P/J100

S24

SHIFT

SPACE

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PAGES

11,

26.

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IDENTIFICATIONS

ASSIGNED

FOR

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TEXAS

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TI-99/4A

MODEL

PHC004A

MAIN

BOARD

36

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SCHEMATIC

NOTES

PAGES

11,

26.

UNE

IDENTIFICATIONS

ASSIGNED

FOR

REFERENCE

TEXAS

INSTRUMENTS

CC2

TI-99/4A

MODEL

PHC004A

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INSTRUMENTS

TI-99/4A

MODEL

PHC004A

MAIN

BOARD

31

5.14V

11.83V

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30|44|40

TEXAS

INSTRUMENTS

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TEXAS

INSTRUMENTS

TI-99/4A

MODEL

PHC004A

MAIN

BOARD

29

Texas Instruments SAMS TI-99/4A PHC004A User manual

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