Sharp Mz-80a User manual

,

SHARP

PDSM9S1

01

O-MZ

Personal Computer

Z-BOA

IFEATURESI

• The

MZ-80A

is

a

full

-fledged personal

microcomputer

equipped

with

B·blt microprocessor

(l-80)

and it can

meet

a variety

of

applications like hobbies, educations, office works, controls (of

apparatus in every industrial fieldl,

etc

.

• It

is

a

compact

desk

-

top

type,

itself a

simp

lified

unit

including CPU

board,

CRT

display,

casse

tt

e

tape

recorder

and

keyboard

all

together

.

•

The

keyboard touch

will

satisfy professional operators, and numerical

input

keys are provided.

• Speaker (3 octaves)

and

clock function are built in.

• A video

RAM

of

2K

bytes

is

provided

to

facilitate

edition

aided

by

CAT

display.

•

• Memory extensions

is

allowed

up

to

4BK bytes in the board.

• Four types of I/O cards for peripherals such as a floppy disk and printer

ean

be

added

by optional

extension

units

.

•

SHARP CORPORATION

,

Contents-------------

Specifications

...............................................•....

1

Trouble shooting guide

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

: . . . . . . • . . . . • . .

..

3

CPU

board section

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

. . . . • . . . . . . . . . . . . . . . . . . • .

..

4

Display section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

..

11

Cassette tape recorder section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

..

15

Power supply

section.

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

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

'.

. . . . . . . . . .

..

19

Circuit diagram and printed wiring board

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

21

Disassembled

view

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

35

Packing method

....................................•.............

,

39

Replacement parts

list.

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

..

40

Caution in Service

it

Maintain the safety and protecting ability

of

the apparatus

after

serVice.

it

High

voltage shall

not

be rised

to

excess voltage so as

to

prevent

this apparatus from the extra X-ray radiation.

I

• General

CPU

Z-80 Clock

function

Built in

Memory ROM; 4K bytes (Monitor) Music

function

Built

in

ROM; 2K bytes (character generator) Editor Cursor

control;

"up",

"down",

RAM; 32K bytes (dynamic

RAM)

function

"right",

"left",

Memory extension; 48K bytes

"home",

"cleary

home"

(max.) Edit key, Delete key

RAM; 2K bytes (video RAM) Roll

up

and

roll

down

Display

9"

CRT (green display) Power supply AC

220V

± 10%,

50

Hz

8 x 8

dot

matrix. AC

240V

±

10%,50

Hz

Characters;

1000

(40 characters x

25

lines) Power

Cassette Standard

audio

cassette tape

consumption

Approx.36W

Data transfer speed;

1200

bits/sec. Temperature Operating

temp.;

O°C

to

35°C

Data transfer system; SHARP

PWM

Storage

temp.;

_15°C

to

60°C

Sound

output

400mW (max.) Humidity Lower

than

80° during operation

Keys layout Number;

73

keys Weight Approx. 10kg

ASCII standard Width;

440mm

(alphabet capital letter, figures), Dimensions Depth;

480mm

Small letter, Graphic, 10 Numerical Height;

260mm

•

CPU

Board Section

CPU

Z·80; 1 pc Programmable

8253

1

pc

ROM

Monitor; 1 pc (4K bytes)

counter

Character generator; 1 pc

(2K

bytes)

Programmable

RAM

Standard; peripheral

8255

1 pc

16K

dynamic

RAM; 16 pcs. interface

(32K bytes)

Video RAM; 1 pc

(2K

bytes)

• Power

Supply

Section

Input AC 220V ±10%, 50Hz

AC

240V ±10%,

50Hz

Output

DC12V

DC5V

DC-5V

-1-

• Display Section

I. General specifications

11.

Electrical specifications

Size

9"

Video

output

4OVp-p standard (35Vp-p limit)

Frequency 60Hz (vertical), 15.7SkHz (horizontal) Resolution Horizontal These patterns

of

the

11

left

in

the

center

ofthe

picture must be clear.

Power source

DC

12V,

1.lA

±10% Non-linearity Horizontal;

±8%

(±14% max.)

distortion Vertical;

±8%

(±12% max.)

Picture tube Cl0M36P31

or

2728B31; Geometrical Pincushion dist.;

1%

(2%

max.)

9"90°

deflection

explosion proof type distortion Barrel dist.; 1

%

(2%

max.)

Trapezoidal dist.;

1%

(2%

max.)

Heater; 12V. 7SmA Parallelogram dist.; 10 (2.So max.)

IC

2 pes.

High

voltage Zero beam; 11.0kV

(10.0kV, min.,

Transistor 7 pes. 12.0kV, max.)

Diode 13 pes. Power supply DC12.0V, 1.0SA (1.2A max.)

Working range 12V ±10%

Sound

output

400mW max. (440

Hz)

Scan size Horizontal; 10% (lS% max.)

Speaker

Bem,

round dynamic type Vertical; 10% (lS% max.)

(320)

Horizontal

Control knob Volume lock-in range ±300

Hz

(±100Hz limit)

Brightness Vertical

lock-in

raniJe

-12

Hz

(-6

Hz

limit)

Working Audio

440

Hz

(OdB)

-10°C

to

SOOC

friquency

-lOdB

±4dB

at

100

Hz

temperature characteristic

-12dB

±4dB

at

10kHz

. Sound maxi- 400mW

at

440

Hz

mum

output

• Cassette tape recorder Section

System

PWM

recording Biasing

DC

system

Power source

SV

±0.25V (rated) Erasing

DC

system

Rated amperage Wait; 2mA Playback 1m sec.

to

SOO/-l

sec. (standard)

Record; 70mA (TEAC test tape) sensitivity

Playback; 7mA (TEAC test tape) Input level Below 0.4V

("l")

Semiconduc· 4 transistors Over 2.0V ("H")

tors 1

IC

Input Over

10kll

(record jack)

4 diodes impedance

Applied tape From C30

to

C120 Output

level

Below

O.4V

("l")

Over 2.0V

("H")

Tape speed 4.7S cm/sec. Working

-10°C

to

SOoC

Track 2-track monaural

type

temperature

Motor Electronic governor motor (12V) Storage -2S

oC

to

70°C

temperature

NOTE

Specifications and appearance are subject

to

change

without

prior notice for improvement.

In

such

a case,

the

explanation here may be a little different from

the

product.

-2-

The machine comprises five main units, CPU board, display, cassette

tape

recorder,

keyboard,

and power supply

circuits. For a quick solution

to

most

operating difficulties, first

consult

the

chart

below

to

find which section

of

the

machine

is

subjected

to

the

trouble, and

do

the

checkings according

to

more

detailed instructions given

in

the succeeding pages.

Start

Switch

on

Yes

I

s

the

cassette

~ecorder

normal?

Yes

End

No

-3-

Check

for

the

power

supply

circuit.

Check for

the

CRT

display.

Check for

the

cassette

recorder.

Check

for

the

keyboard.

Check

for

the

CPU

board.

CPU BOARD SECTION

The CPU

board

is

composed

of

the

following six blocks. When it

gets

in

trouble,

first

locate

which

block

is

concerned

with

the

trouble,

and

to

check

for its

corresponding

circuits;

the

wiring

diagrams

of

every block

will be

shown

separately.

CPU

in

trouble

Display

block

No

Cassette

recorder

block

Keyboard

block

Audio

block

Clock

block

No

Gets

in

trouble

instantly

with

power

on.

No

Yes

•

Checking-methods

of

each

circuit

Check

for

video

RAM

circuit.

Check

for

IC50

(8255)

and

its

peripheral

parts.

Check

for

IC50

(8255)

and

its

peripheral

parts.

Check

for

IC47

(8253)

and

its

peripheral

parts.

Check

for

IC47

(8253)

and

its

peripheral

parts.

Memory

circuit,

Reset

circuit

and

its

peripheral

parts.

1.

By

touching

IC

insulating parts by fingers:

'.:

If

they seem

too

hot

by heat generation;

IQ.oi~"j:fefl~ctive'-IC

load

-4-

~r(~':'\

V

;~:~.'~,

'l.~/

/

• Display Block

DO

-Bus

driver

07

-

~

-'--

--

WR-

RD

CSD

~

/

AO

I

)

A9

Who

le reversal

1.

Sync. signal

is

not

produced.

2.

Video signal

is

not

produced.

3.

Irregular display

characters

4.

The display

is

positionally

deviated.

5.

Position

is

correct

but

characters are abnormal.

Character

h

:>

Video

signal

generator

~

Shift

register

<~/:.

L )

BLNK

).

Sync.

signal

-

I

Video

'\/'

RAM

L--

1"1

Display

~

Oscillator

V

controller

circuit

Address

selector

~

C~D

T

Block

Diagram

of

Parts

around

Video

RAM

Vertical sync. signal: Check

for

pin @

of

IC20.

Horizontal

sync. signal: Check

for

pin00f

IC20.

Is

V·GATE

signal

for

pin @

of

IC2 high level?

Yes; IC2

No;

IC50

Is

V-BLANK

signal present at pin ®

of

IC20?

Yes; IC20

No;

IC2

Is

H-BLANK

signal present at pin

CD

of

IC20?

Yes; IC20, IC31

No;

IC2

Does pin ®

of

IC8 develop video signal?

Yes; IC8

No;

IC2, IC10, IC4

Check IC14,

1<;:20.

Check IC21, IC22, IC26, IC27, IC32,

IC33

Check IC15 and IC16.

-5-

•

Cassette

recorder/Keyboard Block

PC1

D7 -\

PC5

PC4

PC3

-I

LO

In

'"

~

DO

Q)

u

-

~

e

RD c

WR

-

~

Q)

.r:

PA3

Q.

-

.;:

~

Q)

"-

Q)

:0

cs

co

PAO

E

-E

~

Al

Cl

PB7

e

-

0-

)

-

AO

RESET

PBO

r

...h

r

J,

I

1 l

I I

t-'

1)

L

Motor

controller

I"

I

Decoder

I

1,

I

~

I

J,

L

-------,

WRITE

READ

SENSE

I

Cassette

I

MOTOR

I

______

-.1

------1

9

~

o

I

Keyboard

H I

) i

A :

_______

J

Block

diagram

of

Parts

around

Cassette

recorder/Keyboard.

1.

"LOAD"

operation

is

impossible.

2.

"SAVE"

operation

is

impossible.

3.

Motor

doesn't rotate.

4.

Motor

doesn't stop.

5.

Key

input

is

ineffective.

Is

output

signal present at pin Q)

of

IC10?

Yes; IC50

No;

IC10

Is

output

signal present at pin @

of

IC50?

Yes;

ICl

0

No;

IC50

Is

voltage at pin ®

of

IC39 at

"Iow"

level?

Yes; IC4,

01

No;

IC39, IC5

Is

voltage at pin ®

of

IC39 at

"high"

level?

Yes; IC4,

01

No;

IC39, IC5

Check

for

IC52 and IC50.

•

Audio/Clock

Block

RD

----;

WR---i

Programmable

counter

(8253)

"-

--------------

~-'"

------------

-------.--------~---

31.5KHz

")

_

~

Clock

function

INT

J

1/2

frequency

division

I-------C>

Audio

output

CS

----;

A1

------1

1-----<

2MHz

AO---L

____

~

WR----1

CS

------1

RD-----4

Latch

Oscillator

circuit

for

Tempo

L--,-

_____

..4

DO

Block Diagram

of

Parts

around

Audio/Clock

Block

1.

Abnormal sound

output

2.

Clock

function

is

abn·ormal.

--r,.,..,,

__________

..

___

---------

Is

output

signal present

at

@

of

IC47?

Yes; IC45, IC48

No;

1C47, IC51

Is

31.5KHz

signal

input

to

pin @

of

IC47?

Yes; 1C47 (8253) and surrounding are

faulty.

No; IC20 (Check

if

8MHz

signal

is

supplied

to

pin @

of

IC20)

-7-

~-~-~----~

~~--~---~---~

•

Memory

Circuit

Block

Data

selector

WR

RAM

block

07

DO

Memory

control

circuit

ROM

A15

\

A12

CPU

control

Bus

AO~All

DO~D7

Block

Diagram

of

Parts

around

Memory

Circuit

1.

Reproduced picture shows

"panic".

2.

Error display

or

misoperation

is

caused

as

a result

of

program

execution.

3.

Returns

to

"MONITOR

SA-1510".

4. Error

is

caused

after

a long operation.

Check

for

the

following:

ROM, IC46, CG,

IC13

(CPU) and surrounding

circuit

Address bus line

Data bus line

Control

line

RAM

(by using

RAM

checker),

RAM

check

RAM

check

RAM

check

~8~

*

How

to

Use

RAM

Checker

Remove

monitor

ROM from

the

socket

("M-ROM"

marked

on

the

PWB)

and

insert

RAM

checker

into

the

socket

and

turn

on

the

power

switch (the

picture

gets

"panic"

for

about

1

second):

then

the

following

RAM

TEST-l

and

RAM TEST-2 will be

automatically

carried

out

from

the

address

$1000

to

the

maximum address

and

the

tested

results

wi

11

be displayed_

The following

is

an

example

of

the

testing

performed

with

the

standard

set

(with RAMs being all normal).

Note: RAM 32K

bytes

RAM

TEST-l

RAM

TEST-2

1) RAM

TEST-l

1000-0K

6000-0K

00

FF

2000-0K

700o-0K

00

FF

3000-0K

800o-0K

FO

OK

4000-0K

5000-0K

9000-ER-9000,00,7F

In

the

range from

the

address

$1000

to

the

maximum

address,

data

$00

and

$FF

are subjected

to

auto-

matic

write/read

test;

if

error

is

caused,

"ER"

mark

is

indicated in

the

unit

of

4K

bytes_

In

the

above table,

3000-0K:

this

means

write/read

operation

has been normal

from

the

address

$3000

to

$3F

F

F_

9000-ER-9000-00,7F:

this

means

there

exists

error

somewhere

from

the

address

$9000

to

$9FFF;

this

error

is

because

the

standard

set

is

provided

with

up

to

$8FFF

but

with

no

more address, so it

doesn't

show

a

malfunction

of

RAM

itself.

An

example

showing an

error

really caused:

200Q-E R-235B-00, 01

An

error

is

caused in

the

addresses

$2000s;

namely,

although

data

$00

has been

written

in

the

address

$235B,

its

read-out

data

is

$01.

2) RAM TEST-2

Write/read

test

is

carried

out

with

the

following

data.

(a) Write-in

data

$00

(from

the

address

$1000

to

the

maximum

address)

(b) Write-in

data

$F

F (from

the

address

$1000

to

the

maximum

address)

(c) Write-in

data

$00

(from

the

maximum

address

to

the

address

$1000)

(d) Write-in

data

$FF

(from

the

maximum

address

to

the

address

$1000)

(e) Write-in

data

$FO and

$OF

to

be

entered

alternately

(from

the

address

$1000

to

the

maximum

address

and

vice versa).

The above

table

(RAM TEST-2) shows

all

the

items (a)

thru

(e) are normal -

the

indications

"00",

"FF",

"00",

"FF"

and

"FO"

correspond

to

(a)

thru

(e) respectively.

An

example

showing an

error

really caused:

RAM

TEST-2

00

FF

00

ER-23FF-Ol

From

the

above, it can be seen

that

the

tests (a)

and

(b) are

both

normal

and

that

although

data

$00

in

the

test

(c) has been

written

in

the

address

$23F

F, its

read-out

data

is

$01,

which means

that

an

error

has been caused.

In

this way, which RAM

block

(I,

II

or

Ill)

has been

subjected

to

the

error

is

first

located,

and

then

so does

which RAM

component

having undergone

the

error,

by

the

respective

information

given by

the

RAM tester.

In

the

above example,

the

display

of

"$23FF"

means

RAM

(I)

block

is

in

trouble,

and

the

display

of

read-out

data

"$01"

(with respect

to

write-in

data

"$00")

shows RAM 1

of

the

block

(I)

is

defective.

-9-

Write-in

data

$00

Read-out

data

$01

f~AM

1II.

00

01

02

03

04

05

06

07

I

17

I

18

I

19

I

20

I

21

I

22

I

23

I

24

I

07

06

0 0

RAM n'

RAM

I 9 I I 1

I

10

I I 2

I

11

I I 3

I

12

I 4

I

13

I 5

I

14

I 6

I

15

I 7

I

16

I 8

I)

I

-~-----~"-.~

~

-----~-

~----------

-" -_._-----

05

04

0 0

03 02

01

0 0 0

RAM

(I)

$1000

~

$4FFF

RAM

(Il)

$5000

~$8FFF

RAM

(Ill)

$9000

~

$CFFF

00

IT]

Error

--

to

occur

• Wave

form

of

Each

of CPU

Board

-------

---------~~

------~----~------------.----------------.

At

11

of

le

20

(31.5

KHz)

At

Pin 4

of

le

3

At

Pin 8

of

le

11

(Horizontal

Blanking

Signal)

At

10

of

le

50

(Vertical

Blanking

Signal)

.~---~-----+----------------+---------------1

At

10

of

le

20

(Vertical

Sync.

Signal)

-

10-

At

4

of

le

3

Write-in

d3tJ

$00

Fiead-out

data

$01

DO

01

0:)

D3

04

0

,-

,)

D6

D7

"'\iv1

ill

I

1'1

I

IR

I

I 1q I

I

?ll

I

:'1

I

??

I

L)I

I

I',;

]

L--

I

07

o

f

-<

~'\

~\J'I

"

1C

TI

I

11

I

1?

I

n_~

I 1

~

I

I'

I

L"

I

06

o

"t\;\

1

I 1

I 2

I \

I

,I

I s

I

tl

I

I j

I I

I

05

o

04

o

03

02

01

o

RAM(l)

o

o o

o

$1000

~

$4FFF

RAM (Il)

$5000

~$8FFF

RAM

(Ill)

$9000

~

$CFFF

DO

Error

--

to

occur

•

Wave

form

of

Each Pin

of

CPU Board

At

11

of

IC

21)

(31,5

KH,)

At

-4

of

IC 3

- T

!

At

8

of

IC

11

(Horizontal

Blanking

Signal)

AtPin

10

oflC20

(Vertical

Sync,

Signal)

---------

----,---

------

-

----------

-----------l

I

At

10

of

IC

50

(Vertical

Blanking

Signal)

At

4

of

le

3

_________

-1-

_______________

--'--

______________

----'

-10-

....

I

Audio

signal

Video

signal Contrast

Vertical

horizontal

sync. signal

+12V

Power

supply

Video

amp.

02001

02002

t

Beightoe"

Vert. sync.

signal

,-------------

Sync. amp.

02003

To video amp.

To sync.

separator

To

vert.

circuit

To audio

circuit

Horiz. sync.

signal

To

horizontal

circuit

To

FBT

circuit

To CRT heater

Vert.osc.

amp'/output

amp. IC2001

ttt

V-HOLD

V-LlN

V-SIZE

AFC H Horiz.

02003,

osc.

02004 02004

~

H-HOLO

Volume

Horiz.

drive

02005

Audio

signal

amp.

IC2002

Video signal

Horiz.

output

02006

Block Diagram

of

Display Section

)

I----~IIO

~~~

Speaker

Cl0M36P31

or

E2728B31

9"

'\'+-

HV

H~

'\

• • Middle voltage

FOCUS

F.B.T

c

-

(J)

-C

~

en

~

-I

-

o

z

• Trouble Shooting Chart

Problem 1: No picture appears.

[

No

picture

1

Nri

Check CPU board. I

NO

l Check I

CPU board.

Only

HCheck Check

VR-2002

YChKk

Video

Check

02001.02002

and

r raster

+12V

power

~

input

signal. -video

vide0-40V

power

supply. appears. Yes

circuit.

supply.

--

Yes

Neither

(02009.

02010

L..>

raster

nor

02007)

picture

No

appears.

rl

Check

CRT

plug. I Chcek

middle!

Yes high voltage

J

--.j

Defective CRT. r

rectification

Check Yes

(02006,02009

and

ri Defective

CRT.

FBT.)

L..."

CRT

heater. Yes

~-

Check high

voltage at

K,

r---

Check

AFC,

~

G1,

G2

and

~.

Check

horizontal

G3

of

CRT.

No

FBT

circuit.

oscillator

and

No

drive

output

circuit.

Problem 2:

Sync

operation remains ineffective.

NH

Check CPU I

Neither

Check sync.

board.

r-"

horizontal

nor

separation

(02001

vertical sync. and

020031.

operation is

llsthere

r ineffective.

sync. Check integrating.

signal?

Only

vertical

Circuit

(R2030

to

R2023.

Yes sync.

operation

and C2011

to

C2013).

is ineffective.

Only

horizontal

Check

AFT

circuit

--10

sync. operation (Check

point

(j)

output

of

is

ineffective.

FBT.

R2030.

C2021.

R2033.

R2055

and

C2055)

Problem 3: Raster

is

too

narrow.

N~

Chcek

V-HOLD

VR,

I Check

C2010

and

R2014.

Is vertical asciI·

latior

waveform

f----

No

~

R2016

and I

normal (at

@)

C2007.

NrlDefective

IC2001.j

of

IC2001)?

Is

input

waveform

......

of

IC2001

(at

-

Yes

(7))

normal?

Is

output

Yes

...........

waveform

of

IC2001 normal?

r--Y'Check

deflection

coil

(C20161.

Yes I

Problem 4: No sound comes

out.

Again set

correct

program.

Is

there

audio

signal?

.-----.ot

Check CPU

board.

Yes

Is

input

signal

of

IC2002

(at

pin@)

normal?

-12

-

No

Yes

Chceck

VR.

R2050and

C2043

Is

output

si{Jlal

~~C2002

1---1

(at

pinl,J,)

normal?

Defective IC2002.

Check

C2053

and

speaker.

--.-

.-

•..

_---

.~

-._._._._------_.-

..

-------~---

-~~-.-----

•

Waveforms

of

Display

Section

Video

input

signal

Video

output

signal

Video

output

signal

CD

ell

CID

+[1111[[

Jl

·+llllilll

I111111

'+~I~~~

'

..

_-

~111I~1

5ms 5ms 5ms

Sync.

input

signal

Sync.

signal

amp.

output

Vertical

sync. signa;

@ @ ®

Tuu

T'l

~'-

fr-

1

r

12r

~

1V

..

-

20l"s 20l"s 2ms

Vertical

oscillator

Circuit

Vertical

output

waveform

Vertical

drive

collector

waveform

1;

@

.:l

u~

Tn

l T

'O]LJ

IV

~

'if

t

ov

5ms

1.SV

5ms

Voltage

at

®

of

RH·IXOO15

Vertical

deflection

coil

voltage

waveform

Vertical

linearity

circuit

waveform

l])

ID

ltJl

-f

~

"""1\

~

/'

~

1.5Vpp

8Vpp

L I

~

t

lJ

~J

5ms 5ms Sms

Horizontal

sync. SIgnal

waveform

AFC

waveform

FBT

waveform

@

1])

.1])

·ffl

n

1-

l

T.~

4V

7V

'LJ

I

5V

, .-

20l"s

201l

201"5

-13-

Horizontal

oscillator

waveform

1ll

5V

lit

OV

20~s

Horizontal

drive

collector

waveform

@'

15Vpp

1

20~s

AFC

pulse

@

T

160V

20~s

Audio

input

signal

Horizontal

oscillator

emitter

waveform

Horizontal

oscillator

output

waveform

\tT,

20

{(j.

~

5V

'"

OV

20~s

2O~s

Horizontal

output

base

waveform

Horizontal

output

pulse

5V

lM

®

20~

20~s

Middle

voltage

FBT

pulse

Video

power

supply

pulse

-----------~--------~----~~--------J

2O~s

Audio

output

waveform

-14-

ov

2O~s

The figures encircled

by

0

in

the

above

refer

to

those

of

"Wiring Diagram"

---

"Check Points

of

Waveforms".

1

~

i

JLJ1Jl_

I

....

(J1

I

JlJlJL

Play

button

Power

supply

o-o0~

for

motor

~

G

0

WRITE

READ

: I

Erase head

c

~

I

'--

..

•

Record/playback

head

Differentia-

tion

circuit

R3005

C3002,R3005

Amplifier

circuit

I

03001,03002

+5

v

-

Amp.

circuit

03003

Amp.

circuit

Limiter

circuit

IC3001

(1/2)

Block Diagram

of

Cassette Tape Recorder

TAPE

~

en

m

-t

m

~

):>

'"tJ

m

::D

m

o

::D

c

m

::D

(f)

m

o

....

6

z

""

{~\

'g:

t{:

(;:

!~

"''*'"

.C~

~r..,:

§

-0.

~

ill..

• Trouble Shooting Chart

Problem 1: Even if

the

play

button

is

pushed, neither motor

rotales nor tape moves.

Yr-1

Electronic

governorJ

motor

defective.

Check

for

motor'

voltage:

see

Nri

Switch

defectiveJ

if

there

is

+12V

t--

between

M+

and

M-.

Is voltage

at

the

switch

N~

(inter·

locked

with

the

I--

play

button)

in

high level? Check

for

vOlt(!)

at

cheak

point

4

--<

(SENSE):

it

must

be

Yes OV

with

switch

on and

+5V

with

switch

off.

Problem 2: Record (SAVE) operation

of

program

is

impossible.

N;1

Switch defective.

See

if

the switch SW3001

No

surely gets

in

action 1 Check

for

CPU board. I

when the record

button

I-

is

pushed.

+5V

must be

Yes

r-<

f----

No

Does there

come

present

at

check

point

N~

SW3001 defective:

@.

any signal

tr®

r-

Yes check

point

6 ?

Is

there

any

check

for

R3002.

'-i

signal present

I--

Yes

at

the

base

of

03001.

Is there any signal

present

at

the

Yes

record/playback

head.

Problem 3: Playback (LOAD)

of

program

is

impossible,

or

error

is

caused.

Ye.:.! Make

su~e,of

the

tape-'

I 1start POSition.

r-------~

r---------------~

Does normal

waveform

arise

at

@?

No

Check

for

power

supply

+5V

of

CPU

board.

And

check

for

plug

and

cable

(6

pins).

H

Check

for

power

l--

No

supply

+5V.

I

No

Check

for

IC3001,

r-

each resistor and

SW3001.

The waveform

is

not

normal

with

much

nOises,

or

no

waveform develops.

U Check

for

1_

Yes 1each voltage. I.

Check

for

+12V

power

supply

circuit

(for

motor

in

tape recorderl and CPU

board.

Check

for

+5V

input

voltage I

and

R3024.

Y11

Record/PlaYbackl

head defective.

f--

Poor

contact

of

SW3001.

Check

for

Q3001 and

Q3002

.

.....

Is voltage applied

to

the

No

erase

head?

Yes Doesn't

the

erase

.--

head operate because

of

SW3001

in

trouble?

output

voltage

waveform

~

Check

for

the

size

of

~

Yes

of

Q3003.

Much

noise

-16

-

Check

for

around

Q3003.

---..

Azimuth

adjustment

The voltage

of

the

record/playback

head

is

too

low.

is

improper.

•

Waveforms

of

Cassette

Tape

Recorder

1st stage amp.

output

waveform

CD

~

\Ni'

(

'~

Lp

1

Operational amp. input waveform

@

Tt

1'1

f1

1.SVpp

~v

" V V v v

~

_w.

Record input waveform

(J)

Te-

e-

-

r-

1.SVpp

1

L-

-

Head

input waveform

®

T~

i\~

\\

6Vpp

I1

/ VV

Operational amp. input waveform Operational amp. input waveform

@ @

L

6mv~

pp

1.SV

T

OV

Operational amp.

output

waveform

Output

waveform

@ @

T T

4Vpp

5Vpp

I

~

---.L

Record amp. waveform Record amp. waveform

@ ®

l~

r-

e-

r-

T -

e-

4.SVpp

PP) 1

~

~-

'-

"-

The figures encircled

bvOcorrespond

to

those

of

"Wiring Diagram" -"Check Points

of

Waveforms".

-17-

Sharp MZ-80A User manual

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