Radio Shack Hardware Manual PC 1 Service 19xx Tandy Text

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TRS-80 Pocket Computer and Cassette
Catalog Number:

Interface

f JJJOJ

TABLE OF CONTENTS
1.

SPECIFICATIONS

2.

BLOCK DIAGRAM

l

3. LSI
A.
5.
6.

7
8.

3

SIGNAL DESCRIPTIONS

BEFORE SERVICING

]4

CASSETTE TAPE & INTERFACE
CASSETTE OPERATION

CHFCK PROGRAM
CIRCUIT DIAGRAM PARTS 4 SIGNALS POSITION
Operation

circuit

diagram

Operation P.C.B

Key

i

<

i

14

I5

22
28
23

24
„.

I

^

Key P.C. B
26-3503 uicoil

jq



fNUH
KMMVWIt

m m m

ia

*:

«^

I4"i

5

6pc

[-_

JLI

7

ssl

s'

s

(T ej ce

3 E

ra cr

is

i

->YS

<

i«j

e

Display
• Display

tube:

•
•

method 5»

Display

LI-80I7JI.

Display capacity: 24

" dot

matrix liquid crystal

columm (alphanumeric; and tymboh)

Basic functions
Computational rapid ty

1

dt^ifsof mantissa ind 2 digits of exponent.

2

Comptiia:ional method:

According

Capacities:

1'iogram

formula (with priority consideration arid judge function)

lo maiheirntiral

memory; M24 steps, max
Data memory;
Fixed memory
20 nxmoilei
Flexible

memory ^commonly

usable »it!i ire prog

78 memories, max
£ ktniti. as ttepc, miv
1

W^pw program;

I

SO steps
8 stages

Inpui buffer:

Data buffer.

Buffers:

napes fur parenthesis)
Subroutine buffer; 4 stages
"FOR NLXT" statement buffer: 4 stages
l-'uncliona) buffer. 16 stages (but 15

Arithmetic functions
Acd

(*). Subtract

[-% Multiply

(+), Divide

(,<).

Power

raising

(A)

Logarithmic fuactom:

COS (cosine). TAN (tangent)
ASN (line
ACS (cosine' 1 AT\ (tangent
LOG (common logarithm). LN (natural logarr.hni

hxponenial tunciom:

\i\? (exponential)

Ar&uiar transformations:

DMS
DEG

S-quotO r..'! ;\tr.i ,1 ni.

J

Slgniim fnnrtlnn:

SCN

SIN

Tngonometric functions:
Inverse trigonometric fur.ctlonr

Absolut e value:

(sine).

'

'

).

(decimal notation to sexagesimal notation).
(lexageMiinl notation tu decimal nuiation)

rVBS(|X0

Integration:

Kxccoticn of arithmetic

INT
operation is commanded by

Editorial functions
Cursor

).

<

(right).

shift:

lmetlinn:

INS

Deletion:

DEL

Line control:

I

(down).

T

(left)

(up)

ilie

ENTKR

key.

|ln|

mi iiinnot y

W

Programming language
BASIC (Beginner's

All

p«pose Symbolic Initruction Code)

Power source
Four MR44 

^ct*

"

S

12

T.

:h-ih

h-.h
i

il

VII

1

<

S5

System configuration
The system

(see the

2.

CPUI(SC43I77)«
CPUU(SC43l7S)x

3.

4K-bltRAM(rOM4)*x3)

1.

s/stem block diagram)

consists of (he following components:

4. Display chip

I

I

(SC43I23 «

RAN)

3. with Duilt-in

5.

2ANDga(eUim>tit H'jlirc

additional incoiporatton

Character geritiatoi
Interpreter:

(arctic routine

Pio&aiii execute italciiuul
CdSSCtlt tuillfol MdUlUClil
Cummand ilateimnt
Pointer control (leserved)

v -irii'i

mrinutl

lit

Print tontine

Qj,uei

opentnn

Rprngnitlor: nf printer (reserved)

Piw.resumt control
Clouk

•

The CPU

I

iu.ii;;i,

i

I

'

.

Clojk

centred

ia read key-ii data ur read

don* (or Iho loiuitl of
-

Hup

I'oiver "t I

aritlunebco': operation*

or interpret the cyntnx of the

BASIC

the information lo be displayed, but CPU"

instruction to be execute*] fiom the RAM, and decides what is to be
control of arithmetic sequence, memorieingof arithmetical Jots, and its

(tie

(i.e.,

instruction for deciding

what

is

doei not perfiwm any execution By

I

tlon in proper sequence and acts to provide instruction codelo the f PL

CPU

nop

II

via

to be executed, or determine* and prepare*

itself.

Il

the buffer.

only arranges ihedata and inlorma-

On

Uteothet hind.

CPU D

constant-

the transfer buffer and executes operations pei each infraction or exchanges data, depending on the situation. Although it shares eA«.uiio>! fum-lions and tieifoiai* some auxiliary CPU rolcs.it
ly receives

execution instructions from

does net perform any decision by
Eg- Actions of

CPU I

and t PU U

I

via

itself.

at the lime of key data entry.

irt

kvv u

For

ni ui'.

il

operation of ihe Pocket Computet, the uislructlon code (key code)

a written (mo the

RAM

in the display chip

put through the kcybwitd and converted into the instruction code by CPU I, then this instvis the transfer butler. As CPU D isceivei this inctmciion. CPU II ther decodes
ruction code (display! is transferred to thoCPtthis imtmction display) and executes dlisplay processing Upon the completion of this processing, it notitlei CPU I, and CPU I
(Input buffer) after Information

is

1

11

<

confirms the completion of the vak hy ihe

CPU 11

before lermimtirg their function!.

Overview of
Three

C-MOS RAMs

RAM

(I

—3 chips. 4K bin each) plus RAM

Incorporated

In

the display chip aie used in ihii Pticket

Computet,

ai

described below:

•

Mapol4K-bf.

RAM
103OD/ie>
001

Rtnnn orostor*
IMfi

Prog'am

tipihlpmowflfv

mmonei <¥Y - £
b*oume FOR KEXT

Fined

1«7?
i

^04
Aithojgrt

HiKli

q-.-k.

isgg

RAM

aiea

mainly shar*d by ihe

is

prog-air.,

memories. i( is also usee I'm the subroutine sack.
fixed memories (W. X. Y Z).
.

daia and reserve

FOR NhXT

program

staiemert slack and

.

Map of the KAK1

incorporated xi Ihc Jispluy chip

Tl.cic are lincc IK-Ii.t

KAMs

(12S bytes each) incorporated

in

each display chip (SC431 25).

willi the

following condguio-

t.cns:

DISPLAY CHIP

DISPLAY (HIP

1

DISPLAY CHIP

3

3

IJOIJ

Sdijui display buffet

8-digit display buffer

8-digil display buffet

two
Trarufci btffc:

(MS
Fixed memories

Fixed memories

(A—K.

fiO-step input buffe

1

1

(L— V.

memories]

1

1

memories''

I2S

8-digtt display

4€ byln of

buffer

8-digt display buffer

used as

is

J

display data buffer during displaying

and

also used as a buffet iretrwry for

arithmetical result, during arithmetical operations.

Fixed

The

memory
memory of 176

loial

bvies (fiorr the display chip 2 and 31
1

is

used asa fixed memories.

A—V

(22 memories).

r-iemcy

•

I

'

IfefllH

Itanster buffer

o

memory

liyies (I

and

CPU

equivalent i or f>spl;ty

Chip

1

is

used as a transfer buffer for transactions of instruction*, let ween

CPU

I

B.

Input buffer

Rem lining HO

Syt>s (1(1 me-iioi-ipt e-yiivilent) nf Display Chip

Any

information tnlered through the keyboard

2.

Be

dispJayconieiis are stored by

3.

When an

I

arithmetical instruction

CPU

is

1.

is

and CPU

emered.

its

I

kuserl I'm the in roil buffet as follow*:

stored in this buffet, allowing

up to HO

steps.

Dselecii data.

piocedute

is

stored

in

ibis suffer

by CPU

I.

and

CPU

II

performs open*

lions according to the procedure.

4

When

a

program or reserve program

is

to

be recorded or read out during the execution nf

action tikes place through this input buffer.

the tassctlc control nstruction.

Overview
The coniems

of Display
fhr itaptoy AS indicated

til

by CPU

is

I

reoeiwd by

CPU

cliaric*«l etides. ihey arc transferred to the display buffer in the Diiplay

via ih* input buffer ind are ccnvericd into respective
(hip lluuugh the adjiess data bus.
II

* Designation of 'he display i-n
IJie rolkwitigsiru.'tureii

observed in the display buffer

m

the Display Chip.
Tlu-.c arc

buffer

8 * 40 * 320

in Ifce

JfCOCPt

A« K?

W

*/
A*

\
il-

114

X

O

ii>

I)

1

x

1

bill

(40 tyies) of area

in

the display

Display Chip.

hg: tiitiplay numerical

"4"

tit 113 'VI 111

.0

I

I

I

SI

ss

II

\

F

1

"'

nnnin

"'DOilD
»»Din«n
M+

"'

BDD1D
DDDID

Sll

"S

SI7

H7Qaa«D

sis

SI S2 S3 S4 S5

HiidPiV bat*—

1

1

F
'S33
1

(1

1

II

)

p
Aifcli e>i

|

in

11104

n[

1)102

A5-

The numeral "4"

i)

rm
loijniog

MO*

•-'

T

IHOI

|i

1H02

A5-0

addieis

by CPU II) is cotiTcrtcd into He lele.am character code and earned (hrouah on the address
isvkned with the address A8-AI "OOOOOOCO" to store iheday DNM-DIOI '1000" in the
butler (see above illustration). To store the second 4 biis of thedaia. only A5 in the address in turned *l "
in mike i he
"OUQJOUOO" io store daia "tOOT. In ihe same manner, address "OOOOtXlOl" is sefected for storing the Prst 4-bit data

"Oioo"

for

(to be displayed

data bus. hirst, the segnwni Si
display

icgmcm 52 and

ihe second 4-bttdaia 'OOQi"issioted with the

addies "1X101001)1".

—
for Displaying "4'

Timing Signal*

MSP

mi-

i

HA

ruiJiruuinjinjinjiiiJinjinj

—

t_zz£:

j

HI

m

~u

H2

JT_r
_TLr

Hi

116

_r

H?

XMWA.

SI

v//$/r

*^-^*

HA:

Ucek

frequency

for

me

counter.

^r^r

mis

Mgndl.Hl-HV.geneiaicdliom CPU
DSIP:

V IHU*

i-l

n

LT

114

"

ar

—i_n

U

H3

l,M'

Wiih high level wf

signal

It

counted and decoded

to

perToim iynchiorUzation

wliJi

UK common

D.

lhi» itgnal.pioc*siinft

of display operation

ii

indicated

(RAM

data designated by HI ~- 118

is

»*m out on

Sl~S40).

The dam MOtcd in the
thf ;i

GNU

MHHX*

%

.1
ovpisp
RtlitonMiwr

i«np«»iLue*iiO VOISP

'iX

c pun

*0'

The

liquid crystal reference voltage

tion* that might

cegnde

VDISP

is

generated by the above circuity lo avoid bluncd

display performance (which

would be caused by a

-V

ehaiaden cr contrast

slight voltage variation

h

varia-

the liquid crystal

referencevollaff- VDISP}.

a.

VDD is generated m CPU II. referenced to VGG.
MOS FET i& controlled by the 230K!2

b. The gate voltage of
to compensate

foi

lemptvawre

put 10 regular the vullage foi VDISP.

C. Ref*ren« voltage VDlSPit aiviicc by resistor combinations to provide
VIlKPr nila

14

DI02
DI03
DI03

In- Out

Ditnlav Phio

15
16
17

18

D7a

In'
In.'

Out
Out

**

HtR

I

it

All Kesri

Switch b preyed.

signal

to morr*.«nlari}y

5.1

low

-^

address detignation of the input buffer

for
1

am 1 irmsfer

During dismay: High
During read-in Low

Addtess Bus (for address designation of the input buffer ind

and Display Chip

Oul

Dining icad-m

B6a
B3a

2)

Ma

22
23

B3a
B2a

24

Bla

Out
Oui

30

GND

In

40

51 Ga

Oui

'Trnuini rnrn

41

Sn

Out

Si

On

L

Source voltage (0V)

CPU

ll

During display: Low
During toad in: tutiu

42

M orient arv

_ _ _

1

signal to

Kay Strobe
Key Stfrtbo

r fanslet buffer in

RAM

1).

On ling display

Busy

and

\\\\\ \\

Out
Out
Oui
Oui

19

m RAM

•» \_\_\_V_i_ \_\_

Out

20

buffer

,

signal.
signal.

(High during execution

itiuiticnliiiily lugli

RAM
RAM

10

Addrcts

signal

Address

signal

in

CPU

t)

-

erncration

J ~

^

HdNo.

Signal

pjiw

43

SI 3

44

SI 2

4S
46
47

SI

1

48

SIO
59
58

49
SO

S7
56

In' Out

Description

Out
Out
Out

Key Strobe

Out
Out
Out
Out
Oul
Out

Pressing a key causes it to momentarily go

-LiM.il

Dining display High

51

S5

52
53

S4
S3

54

S2

Out
Out
Out

55

kil

In

56

Ki2

In

57

K13

In

Owing

58

KM

In

Pressing a key causes

5<)

SI 6b
(KiS)

In

Busy

Key input

low

signal

display:

signal

Low

of CPU

During dijpUy:

n

11

to momentarily

go high

(high during execution

t>f

CPU

H>

J*

Low

SC43178(CPUII)
Pin

No.
1

Siinal

Ini'Out

P4

Out

Description

—

Bu/.«i signal

Whert tha buzicr
".Tier ih*

2

4

F3
F2
Fl

ChipEmble signal) Display chip
Chip Enable

1

-"" f^_[~

I

1

1

I—

'

Display chip 3 select sienall

Chip

Out
Out

fcnible signal

1

on High

iv

Oul

Out

5

bWBW

Low

off:

it

C25rni

signal (Display

chip

2 select signal
1

I

aelecl signal)

___.-- -_

During display:

Low

Duung tend-in

Tmm tikiniciilai

ily

h-gh

Foi liquid crystal drive vullige preparation i.Vdd * Vc;c>
Source wluge(**-" voltage of Ihe battery)

6

Vc,c.

In

7

V,;r.

In

e

Xin

In

Basic click (Pulse signal.

li

RESEr

In

All Reset

12

WW

Oul

RAM

256kHz)

Switch input

Data Read/Write signal

During display High

Dining read-in- Turn*

iiiuiiicitiailly

1

luw

**

nnNo

1

Signal

name

men

In/Out

DI03
OIOZ

In/Out

lb

DIOt

In/Out

I?

B8b
B7b
B6b
BSb
D4t
B3b

Out
Out
On!
Oui

14

IE
19

20
21

22
24

B2b
Bib

25

HA

23

DwtfjpttWi

In/Oiu

In/Out

l>.ita

Bus

(for data transaction

Dunne iea.Hn. Turns low

between

-

RAM

and display ehipl

\\\\\\\\

_^_^

Address Bus (for address designaiion of the display chip!

Blb» high. B2b Mow, B3b=bw. B4b-lov. BSb=high B6b = hieh.
B7b«low. BSb=low
Duringdisplay

l>urtng read-In: Turns

momentarily high

Out

Oui
Out
Oil!

Oui

Display sijna'(fommiui signal couniiug pulser

Generated during display
*i

26

MSP

Oui

Display

command

05m r

signal

Dining display- High
During execution: Low

In

LCD display vnhagff
LCD display voltage

In

Supply voltage (OVl

29

VM
VA
GND

30

144

Out

^1

H?
Hi

Oui

27

IB

32

In

(Intermediate voltage of the segmeni lignal)

(High voltage of the segment signal)

LCD common signals

(backplate)

Oui
Out
Out

33
34

Ht>

35

115

Out

36

HI

OU!

3?
38

Vmsp
Vb

In

LCD display voltage I Low vrltage

In

LCD display voltage (Low vdiage of

39

510

Out

H2

Busy

CIV
Low

signal to the

During display:

40

S15
SI b

Out
Out

RcuoiJ

41

42

SI 3

Otit

RiKy

43

.,

Out

Expansion

Remote

signal

1

(Ilijh

of ihe

common

during execution in

CPU

II)

_^**^

tw the cassette tape and prinl

signal to the

signal)

ihe segment signal)

idala.

MT.

tibial i" r*inier.

signal

During display:

^^—-*"

Low

12

.

PinNu

Signa name

In 'Out

49

S6

Out

54

SI

Out

Description

Fot DEF symbol display (engaged" low, aoi engaged:

Fnrtymhnl

display

(SHIFT DFC.,

lilgfi)

KaUCVAD, P.FSFKVF, PKO RUN)

Same waveform as the segment signal
55

Kit

CPU

In

1

BusysfgnaHHighuuiingexecutiujiinCPUl)

(SI 6a)

56

Ki?

In

F.ipantion signal

To
57

H3

b* cimrwcifd to SI 2

Ki4

11).

Primer Busy signal

in

LuW
58

(CPU

A'litll lIlC i^lilllCI i> IIVH

opcuttil

Puntei connection identifying iignal.

In

Low when

ihe pimtei

59

hi 5

In

(asset to recall signal

60

Ki6

In

OM

is

not connected.

key input signal.

IC Pin-out
ic-toiiuBr

|<

HJu*t i-«npui p-tsmvo NASI* iwlr

1

)

nnnnnnn

'""14

13

18

II

ID

'

K

J

in

lltS

ip

mvn id

)

nnnnnnn

,(''

14

H

I?

io

tl

c>:

lay k^J
,fPl„r^1„,

UUUUlJUU

uul1iljul!ju
*

I

A

'

CM)

(iNI'

n:*umn'
'Quiii

AMD-Oft

THOBflBP
Klcti

wit

>

>

(

tfiwi ^~

'«n °"1

in

*»

in

qui

bUt™
c,„

13

>

'

I.N

..

.

BEFORE SERVICING

4.

Disassembly procedure
Remove 2 screws (i) and I screws (b).
1
1 From (he sere* sule. leparate the upper

cabinet

item

the lower cabinet (they are latched togeihei at ihiee
points, A,

B and

C).

Repot ring procodure
]
The bii'-i' of lK« at jihiwetic ftintod board
.

exposed

after

will

the removal of the lower cabinet.

be

You

can check the arithmetic printed board from the back.

Replacement ol the CPU 11 is possible.
3. If the key primed board is to be checked, the arithmetic piiiilcd buaid lies to be bent at a right angle
alter removing the screws )d) anc (el. Inspection ol
2.

CPU 1 b possible
lemming sciew(c).
the

the bizzrr

if

Is

removed

after

LkcI

The hey printed bontd can be dismounted by removing 9 gcrrws
board, so y«. ilonl *plll In* he/ lops.

4.

i

(f>

and 1 screws <$> Tale care as you remove

rtie

printed

i

Replacement of the LSI
1

2.

Only « very fine soldering pencil should be used tot replacing the LSI.
Be sure to first remove the key primed board fiotn the uppei cabinet. If the LSI on the key primed boird is to be removed,
poistbUity of deforming the key
if the LSI s removed while the key ptlnted board Is on the upper cibinci. there is a
rubber with Ute heal of the wittering pencil.

?.

a

Bcsurc tocut each pinof the defeciive K.

-

Measuring current consumption
tVwer source volnge 4.72V
Cuitem consumption:
After pressing the (IN key
After pressing the

OFF key:

5.

Under ftSQuA
Under

1

2(iA

CASSETTE TAPE & INTERFACE

For details of operation and connection, refer to

-Jie

Owner's Manual

for the

TRS-80 Pocket Computer

Notes on suitable recorders
While Radio Slack's CTK-SOA is the intended cassette Recorder, oiheri can b* used The
1.

following totes

Cassettes oi upciMecl tjpci can te used.

3.

Mic input jack must lia« an oipui impedance of IK or leas, wiih a sensitivity level of at least -tmV.
Eaiphone output must Hjvb an output impedance of OK or less and an outpu: level nf volt or more.

4.

Allowable distortion

2.

I

is

-1 %%. *ith frequency response

1

from

14

?

to 4k H?

wy

Im> hclpl'ii

6.

CASSETTE OPERATION

Recording
Recording method

cm
/
Recording formal of pi op am or reserve program

Data

1

= Check

2"8
3

~

4

sum code (after

fcnd

code of recording.

Tim

gap.

composed of

data to be Input

5

-

every s steps or one data

steps of program or reserve

All

*'

all

peered

is

ii

uwd

formal

memory. I

program

"Is",

is

inserted

ai

each line to

(ill

up Hie

lull

80

steps, during

which time the next SO steps of

in ll
Signal

waveform

the tin* of recording

at

Whan a wording *leml"r*k 1« h# recorded. SI 5 k vet low and «8n»i F4 (clock pulse of -4kH/lis .iiiiput du-ini thai period.
When a recording ligral "0" is in be recorded. SIS is set high and K4 output is inhibited during that peiiod U which time the
reverse sinnal of HA (clock pulse
= 2kHz) is carried on lite recording signal
This signilh supplied to the MIC jack of !he tape recorder via the modulation circuit oJ the Cassette Interface.
.»:'

|

Reproduction
Output

signal from the
through Ki5 terminal ot

EAR
CPU

jack of the tape recorder

is

amplified and shaped

m

the Schmitt circuit, to be input to

II.

h^>
MS
CPU

w

II

Jl!

M'U

wv-

C»CV>T

16

Arvpli'icr circuit

CPU

II

Remote
The Cassette

control

In let fate will coltrci the

RKMOTE Jack automatically
O.M7pF
rl

KIMOTI-

.

(or record,

playback and verify commands.

V7 «Ki«

O

(SU)

*feG

(iMI>

U'-452XPisa mono-siablemultmbraUHHo perform tiiggei and resel fraction! from the sirgle chip).
a pulse which KitepenrifM rtn thp limp ointtaiH OfCR a' the tailing edge of the mput ctgnil, and "ti" outputs a
pulw which u dependent on the tine constant of CR at the ruing edge of ihe input signal- The relay operates ON and OHac cut ding to the curie nt flow 10 ihe coil, and b auivatfil when "A" b active and deactivated when "B*' KtCUW.

1'ne

"A" outputs

Startup ol

s

>,<

.

,.,-tt-

.

/ T—mm

r"---"

tool ion ul ihc c<»cirt jj-rdin.i

u

QA
\

Activa'ian of the relay
i:«ictt* to itort runnng)

"LT

QR

\
Oeaetivacior ot the telev
(cassette to nopruonir-q)

17

Testing the Cassette Interface
1

Writing.

'«t data into the Pocket Computor

Firn enter

tesi flats

10 check tlu Inter fact,
^^^^"^

Read

No.
1

ImodeHmodeI

Remarks

^

RESERVE

2

NEW

NEW_

RESERVE

3

ENTER

>

RESERVE

4

1

5

6
7

2.

Display

in

shftI
P.

i

1

2

Z;

»LSHFTJ?A» SHFT ;A<204>

RESERVE

_

Z:P. tf»AT;A(204t

RESERVE

r>Tl-K|

Z;

PRINT * TAT A(204) RfcSCRVE

SHFTI X

X.

RESERVE

8

L#|SHFTi?AT|SHFT|

9

int(k)

10

Sill 1

I]

AI204)

12

bNItK

13

MODFJ

14

MODEl

15

SHFTl ISPi!

16

ENTER

1

;

A(204>

X:

;

1.

3

TAT; A(204)_

X: INPUT

|SK

Dhplcy RF-SF.RVF m.ide

—

RESERVE

=?AT;A(204) RESERVE

RESERVE

|

:

A(204|

:

A (204)

RESERVE

::.(->

= 100

>

KlIN

A(?041=lflO_

RUM
KlIN

I

1U0

Checking the Cassette Interface

Amu ires ihat iiep

hut already been executed.

Read

No.
1

I

in

Remarks

Di iploy

OFF

**

•

Connect tiicCwseUc
Interface to the lape
recorder

3

Connect the Pocket

Computer In

the
Cassette Inurface.

4

[TUT]

RUN

5*

Mako suic
th#

that

RL'N » un

dKphy (u«fMfH»F|

ke/)

5

>

RL'N

16

Pimtijn Tjuc coiieciy.

'

.

Nu.

Read

Remarks

Display

in

>

6

RUN

Pr«a»

RHC aad PLAY

huimn.
'

7

SHMJ Z

1

PRIN1 *TAT;AI2(W|_

RUN
RUN

|KNThR|

H

nie casseliewill run ami

produce *ouid

9

10

>

RUN

The usiclic wi'l slop and
tnnnd mill ct%tt.

>

RUN

Ke*'ind (tie tape to the
beginning .>f tht recording.

>

r:

INPUT #TAT;A(204)

RUN

•

11

12

1

SHFT 1 X

13

I

ENTER |

n

RUN

Press

'11 if

Pl.AYbuuon.

L&aetlc

wi'l iuii

and

produce sound.
14

15

1

Mtl-I

l|SK]

>

RUN

AUU4>

RUN

IHNTtR|

16

\

mo.

RUN

100.

R\

17

The GUMIWW0 siopanO
sound will case.

Push STOPbouon.

fOFFl

18
19

Disconnect ani:sand
castes.

I.

is reqnii-'td if any of following conditions occur*
lfcassettestm!torunatStep6.
If cassette fails to run or no jouml is heard at Step 8.
If cassette does not stop at SicpO.

Inspection
1.

2.
3.

4. If

no sound s heard

U. Repeal the procedure
1

at

it"

Step

1

3.

ihc following occur*:

" » displayed

When "5

at

Step 13, repeat operation fnim Step 10.

repeat Ihe procedure frum Step 5 after emetine.
this . detailed inspection
2.

When 'MOO.'

is

ii

If ihc

If ihe saine indication is Mill

on the

display.

tame indkatixn remains on Ike display even after

required.

not displayed

display, repeal ihe

"A(204)=100".

procedlM

at

Step 16, repeal operation from Step 10. If the specific Mfotlon doe* Ml appear on the
"Af204l= 1 00". If the specific indication is not to ippe-ar on the

front Step 5 after entering

display even after this, detailed inspection

Is

required.

10

A

Repairing the Cassette Interface
P'(W)f»m

1

1

N T

#

i)

•

|

A (201)

:

1

U

.

1

t>

r

i

i

i

A U 5 E

P

Us? ibe following procedures ioe>v»luaie the Cassette

Ititertaie

Tape rwuiuVi

Plug

Read

No.

Displjv

in

1

ii

lak|

KtM

c

OTI

ReaMika

PLAY MX

STOP

i|off|)

1

t

onnei't l

ompuier io

Interlace.

[ON]

2

>

HUN

o

o

Uelermine recording
loca'.iiin oi>

>

3

RUN

o

O

o

o

o

Make

the tape.

sure liul

111;

upe

docs not run.
'

CSjSHKTlf

4
s

fcNItP

I

CS.TA

RUN
RUN

1

o
o

o

o

o

o

o

THa

lap* ttirtc tnnin
jnJ u'cording tound will

be heard.

>

h

RUN

o

o

o

o

Hie
tlie

Miutiil will cext.it

upe will

">*'
7

>

RUN

o

o

K

>

KL'N

o

o

o

Cl.O/fA

RUN

o
o

o

o

o

o

9
iU

CLO.? (SHFTlTA
1

trVI!-K

RUN

|

is

and

stop wlteu

displayed.

RewjiJ lupe to tic beginning!)! ihc ICUHUDK.

o

o

ine display ccnietiis

will

disappear, 'apt will s'.an
aid .oiinl will be pro-

duced.

>

11

o

o

RUN

12
13

RUN

lOFFl
1

0= Cunneciedor

2G

activated

o

Sound and tape \>ill Mop
when">"isdispaycd.

)

|NOTES]
2.

Check the Com puw.il th* cassette tape keeps running in Step 3, fab to run in Step S.ot the tape does nor slop
Check the recording circiii! of the Interface ifno recording sound is audible at Step S.

J.

Kr»

1.

sound

audible

ft

a>

Step ID, playback anoihei recorded tape to check

il

sound isiuciblr with that tape

audible with that tape, check the reproducing circuit of the Intetface. If sound

is

If

in

Slep 6.

tound

is

not

audible with the jecond tape, check

lecordinR circuit of the Interface.

ihe

Read

No.

Ketnaiks

Display

in

|

RUN_

RUN

No tap*

Dim
KU I*

kbcokdor

i

RUN

Reco'dinff sound ceases and "10."

i

RUN

1

s

z

RUN
IbtSIcK l^-

»5and

1

12 pins

TCXSJHBP

ot
lor t>«ii water t

recorder motion.
soufiu

is

auuimc.
is

displayed foi about

1(1111

._.-.. 1-

— —
—<«ord«ig

»I«y

-»fU- Imsecmm

j

L>eact^3tK"> oi in« r*iav
(gasaeiio Ldpe lu

Cassette

ONjOFF

tiw)

conitol must be pioperly executed

when the above

21

signals ate observed during

cxeiutwn of program.

—

1

*

CHECK PROGRAM

7.

READ

l> 1

IN
2

1

1

Xw\

2

IALL RESET)

3

8/8 lENTERl

3

t

i

l

1

5

1

1

:

F

^^^^~

ISHF7I

•

8

2 JS1IFTI

2

(1

—i
"

S

B E

[SHU

h

P

ISHFTJ

;

•

ISHET1

E P

8

IKNTHRI

[entek|

A dIeNTErI

[Shi- i| Isi'tl u

11

13

1!

i

1*

..

1'

islie •

17

i

i

15

5

5

5

5

— ——
5

5

1

*

ENTfeRl

i

•

r

k

z

'

T

2

2

3

n

1

()

K,

w

r
T

z

:

»

N

1

*

r

1

—p —

i

1

E

e

k

N

I

1
1

'

s'

T

— ^u
i
'

l

1

T

2
1

'-

]MODfc!

R

SP L A Y

-

1

G

II

i

L

,SMK1|

10

10

.-

1

8

s

5

modbI

f>

8

-

^»

.

1

7

1

4

..»

'1

ii

(fcNlfc-fcl

4

i

7

1

12

iMOIH-i

18

|SHFT|

14

'NOUH'SHFTliSPCl

1:,

1CLI

--

7

S

RAD

ii

[ENTER)

J5

i

i

r

1

f-r

:-

1

i.k

|

,

V

i

(

IS

7

4

I

1

1

K

(i

lENTER,

S

18

[Enter'

-.

ie

{OFF]

L_

|

I

:

I

20
*

1

1

i

i

1

1

si

32
23

24
26
en
i>7

2fi

29
30
1

'
'

I
'

i

as
S3
34
1

1

'

1

1

1

8fi

36
87

ax
1
i

.10

40

i

i

t

1

SVMBOI.

U

)|;i|is|z3

^
j

J

f

SHFT

RAD GfAH DEF JrUK

Dill

E

laavtt

W

bQU>

play'rec stw RBCn

J

t

1

'

i

TRO

•

'.-.

1

t
f

O

^

O


(Ul

o

O

o

_";.

Co)

o

o
'.

<

J

o

i

o
o

(O)
'

*_*

o

'

1

O

G

o

i~

1

"

'vj

o

O

o

!
.

I

'

*

1

32

r

.

CIRCUIT DIAGRAM PARTS

8.

Circuit

i

Diagram

-

-

HE-

C

Hie

i.?Fi

I
"J

ss

'Of
or
I'liirl"! BUSV >l«v!

i

>

i

1

1

fir

(!:

*

o
$11
SIB

ll.ir>

mil'
I'HH

Pivwl

»»

cpu

!S

Or

D

lvt

•

.

(

|w

*»

ii
I*

TTTT

ZI

II.

ft

*

cm
*»ai4liM,

'

"""
Ki>;

i

«.

t>-

:

'

—

fl
vB-

?v

gyggyij

**'

V"

V
ii

23

VV V

n

i»

ii

:0

S

SIGNALS POSITION

Via

f

:

IDI

.

11

LIS

f
~

-Mi

I

-

Operation

P.

C.B.

*

*3 «tb MO!

«•<---'->©

m

w

§

J*

1

«X)U
±-»iwoo«
•i"->.\

o*f

fi*y

So

—

U*L
n

K*OMF

KI9

<*«0

1
WD
SM

J
1

fSOKQ

KH

1

'herniate*'}

ilOOWir

j,

9NB5IP

Hi

_—

B
jr

.

nw*&*toam**t*FnH*9*bfii
*H«r**6*«*ttW«M6*
M BH IM M> «*' M mi **»*
HZ H) AS AI m W W * ilAi
it

>ni

ri

TOP VIE*

*

to

»•

&tfr»WB

J

..

1

To

/J

*

^.^
!/«1

KEY

ID

5i»

Ml

fim

m

Vm

era

BM PW PC

«

lit

BOTTCM VIE*

24

NO*

M

M

A6

M

Hb

•'

HJ AI

W

Key

Circuit

sunn
\i

23

|

M'l.ftl

ill

:

!'i|

••

& && O O
iftinmiu
&

6

I

-

H
In
•
:

I
•
•!

fl

D

^=

3

"a 9

31

a flOM C J

23D

8

-

1

BB
"<•"

;

iPP

s

""'""I

.
Q

ioa

liB

s

a

c

a

t

-

8 g
3

n

Q

3
3

3

1!

3
a i
3

DO2

S

sua
00.

00 D

cccp

KeyP.C.B.

Ml

WMM

4u IB W?

* »* *

S* •« S. J* &. &B S*

S3

l4< ->•

(

n

J»

& &

-V U} to •»

Q D D

Z% &> *B **
~*t ry
*l

fR-U-l

B

H

QEQQD

EQQQEJE1F1QE1Q
E Q

D E
B
D a
nit,

Q Q Q

H

(+>

#ft
op

3

w
•

MH

S
B

1*

loci;

i

Dicrui

sit

rn

I

nio.i
-

*

D'gFLAY

1(1

.3

SEIOOt

?

E

*i

m

i*

MP

P

.

26

-

Interface Circuit

KtUJM>

"»ul

IPl'l

Diagram

_

U

1H10)

can

O

Interface P.C.B.

27

]

9.

PARTS LIST FOR 26-3501

Ret

RS

Description

Nr>

Manufacturer

Location

1

Special sc*e«v

(M2 *

2

Special screw

(M2X a

3

Bottom cablet

4

InsuUto' sheet

5

T^ne for interface

131

Pa'i

Number

AHD15S5

Lx-H*;iU84UtJZZ

AH13-I587

AZ-5633

LX 3Z1032CCZZ
HDECA1765CCZZ

AHB-9P,!V)

P7FTI 135SCCZ2

Ana

PTPEH1C0 2CCZZ

i

A
7

Morfsnt

loclc

plats

plme

90S1

AZ5634

LCH351091CCZZ

Lid tor interface lock plate

ADA-0314

3t'c«(M2

AHLMS8B

1

lor*4<

20

Filter lor

«

Display niask

ART-2987

GFTAA1?46CCZZ
XBPSD2OP09OOO
RALMaiOOBCCZZ
LX-BZ10SOCCZ2
XTPSD20P05000
QCNTM1036CCZZ
PCUSS10S1CCZZ
QCNW 1136CCZZ
QCNCW WD3CC0I
PGUM51190CCZZ
VVLLF8017JE 1
PTPEH1033CCZZ
LANGK1290CCZZ
PPILWI230CCZZ
HDECA1527CCZZ

22

Display

ART-2991

PFiLwi??acr:77

23

Key rubber

2d

Ground son no

25

Key lop

08 key)

26

Key top

(1

27

Key ioplSHFT)<2CpcVl

zh

Kay lop (ENTER)

29

Kwy top (Njmeial)

30

Key iop(CL! <20pcS/1setI

31

Salter/ terminal

9

< 9)

BlJ2?tt

B 7073

10

Special «r»iw

11

Scnr*)M2

12

All reset

twitch

AS-U692

13

Cushion

'or reset switch

\HR

(M2

AHD-1689

x 5)

AHO-1690

x 5)

14

Flexible wire (22 on)

IB

Conrwcicr

to

Rubber connector

17

LCD

'8

Tape

19

Frame

AtAi.2621

'o'C a w«tt«

18pi-.J

tot

'-<'>-

A J 0031

Interface

LCD

ART-2985

AL1180
for

LCD

AHB9953
ART2986

LCD

tor

LCD

AQO430

tL'r

f

—

\h~ ? 3033

VHISC43I 77/1
VHJSC431 78/
VHiTC4Q11UBPl
VHiTC40»9P/
VHi C4056P/

(Key

unit)

lahnl

Cstxm

B

RS
Location

Description
[

resistor

8546

1/BW 143K Zh
Car ben

I/8W

resislor

12. 7K

Ca bon

2*

resistor

1/8W 21 K 2%

lOO^F 10V -807-20%

Co.iokv

(CerCTtit)

220PP 50V itO*

DS1688L1

Diode.

Trie miner

iisok)

LSI (Display thiol TC/312S
LSI (CPU-1).

SC43177

AXX-3034

LSI tCPU-71. Sr.4.tl7n
IC,

1405

TC401 1UBP

AMX-4439

IC TC4019P
IC, TC4066P

flMX-4440

TC4069P

AMX-4442

AMX-4441

1

1

1

1

AX> 3C3^

VHiTC4069PM
VHiTC5514PM

ANCS36EBB

VBC-MT26G

AN0I32E6B

VRD

ST2BY101J

AN0311E6B

VRD

ST2BY223J

AN0281EBB

VRD

ST2BYI03J

AN0371EBB

VRD ST2BY104J

AN0445EBB

VRO-ST28YI05J

Cation Resistor
1/8W 4.7K 5%

AN07A7EBB

VRD-ST2RY477J

Carbon

AN0423E8B

VRD

IC,

LSI (Ram)

Sdidresatoi

1/8W

I.6M9I1P1

Carbon resistoi
1/3W 100 ohm
Carbon

I65J

6%

5*

resistor

1/BW 22K 5%

Cabon

resistor

1/BW 1CK 5%
Carbon

resistor

1/BW 1G0K 5%
Carbon

resistor

I/8W 1Mohm

Fc

594

rtsitlor

1/SW 470K

5*6

ru
ih

29

ST2BY*7*J

Rel.

Deicripiion

No.

1

40

Badge

41

BatWy Wrniml

B

RS
OC^on

Manufacturer
Part

Number

PCB(Keytmt»

AX -8546

PCBICPUunit)

AX-8547

Template

AHB-9959

HBDGE134 1CC2Z
QTANZ1293CCZZ
DUNTK5567CCZZ
OUNTK5558CCZZ
LPLTP1070CC77

Name

AHB9960

TLABZ13fl«;rf:77

flMh.yyei

AHB-9958

4>, -I

label

Carbon

resistor

AN0583CBB

RP-DZ1006CCZZ

Carbon

reiiitor

AM0&84CBB

RR-DZI007CCZZ

AN03O8CBB

RR-DZ1008CCZZ

1/BW

2%

12.7K

Carbon

resistor

1/BW 21K 2%

^~

VariaWeresislcr (250X1

AP7105

RVR-MB510QCZZ

Capacita (Electrolvticl
IDOyf IOV-8lV-2(Bi

ACC105ZJCP

VCEAA1I1AW107O

Capacitor {Cersmicl

ACC221KJCP

VCKVPU1HB221K

ADX1405

VHDDS1588L1

Thc-mistct I160K)

AT-1218

VHHISaRD-SM

LSI (Display OltW TC43I2S

AXX-3032

2;op= 50V ro-.

DS1588L1

Diode.

1

SC43177

AXX-3033

^1 nniU-^l,
11 PTAMTO
Lol
lul
jO*»JI /O

AXX-3034

VHiSC*3125/ 1
VHJSC43177/
VHtSC43 /8/-1

LSI tCPU-1).
1

1

J

1

1

IC,

TC401 1UB&

AMX-4439

VH.TC4011UBP1

IC,

1

040191*

AMX-444Q

VHiTC401

IC.

TC4066P

AMX-4441

VHJ7C4066P/-1

IC.

TC4069P

AMX-4442

VHiTC40S9P/-l

AX X 3035
AN0536EBB

VMJTC5514P/1

Carbon resltlor
1/BW lOOo-vn 6%

AN0132EBB

VPDST2BY101J

Carbon

AN031IE6B

VPD

Caroon resistor
1/8W 10K 5%

AN 0281 EBB

VRDST2BY103J

Carbon

AN0371EBB

VRO

AN0445EBB

VRD-S72BY105J

AN0247EBB

VRD

AN0423EBB

VPO-ST?BY474J

9P/-1

l

LSI

(Ram)

Sdirl resit Tor

I/8W

.«

„

1

6Mohm

VRC-MT26G165J

9fe

resistor

1/BW 22K S%

resistor

S12BY223J

ST2BY104J

1/8W ICOK 5%
Carbon

resistor

1/8W IMohm
Carbon

5%

Resiitot

ST2BY472J

1/8W 4.7K 5*
Fc

Carbon

(if

1/8W 4 70K 5%

resistor

m
th

CO

29

Rpf
v-

RS

Description

Location

ManufacturePart

Number

Transistor 2SC4S8KS

AA2SC458KS

VS2SC458KS/I

MOS FET 2SJ40

AMX-4443

VS2SJ4 0-///-1

Cacaciiot (T;m&Jurnt

ACC104ZCTP

RC.?7inOBCCZZ

Crvti4l (256 kH-|

AMX.2780

RC^SPI0?4CC7Z

Capacitor (Tantalum)

ACClOIKJCP

VCKYPU1HB10IK

ACC103MFTM

VCTYPU1EX103M

ACC105ZCTP

RC-SZ1Q07CCZZ

AN0396EBB

VRD-ST2BV224J

ACC102KJCP

VCKYPU1HB102K

O.laF

10V +80/-2O%

lOOpF 50V ilOW
Capacitor {Tantalum)

lOOOOpF 25V :20%
Capacitor (Tintiiuml
1/tF

10V +8Q/-2Q*.

Carbon

resistor

1/8W 220K 5%
Capacitor (Cframicl

lOOOpF 50V il(Wt

-)

30

EXPLODED V EWC 26-3501)
I

r

«*,

31

1

PARTS LIST FOR 26-3503

10.
Ret.

RS

Dctuitxivii

No.

Pari

Number

AZ5637

GCABA2389CCZZ

AHD-159?

LX-BZ1038CCZZ

Rubber foot

AF-0? 8)

lid

AMD- 1593

01

pin)

*b< lock Dlaie

Ffif.

101 7C.C77

A25G39
ACC106ZDAP

QTANZ1072CCZZ
HDECA1775CCZZ
HDfCA177€CC7?
GCABB2300CCZZ
VCEAAUICW 106G

ACC4/2KJMP

VCQYKU1HM472K

ACC473KJMP

VCQYKU1HM473K

Capacitor (Tantill
0.01/*F 25V ±20%

ACC103MFTP

VCTYPU1EX103M

Capacitor (Tinuil

ACC104MD1P

VCTYPUINXICMM

D,ode.D$1588L1

ADX-1405

Relay

AB-8127

VHDDS1589L1 1
VH.N R57 11 //-I

IC,TC4069P

AM X -4 442

VHiTC4069P,'

AMX4444

VMiTC4528BP-1

Carbon iesi si >
1/8W 10K 6%

AN0281EBB

VROST2BY103J

Carbon

AN0371EB8

VRD-ST2BY104J

AN0445E8B

VH D-ST2BY105J

AN0303EBB

VRD

AN03HEBB

VRD-5T2BY223J

AN0155EBB

VRD-ST2BY271J

AN0423EBB

VRD-ST2BY474J

Battery

1

Wan:ifartu'er

Location

12

Decoration panel

A

ART-2992

13

Oecoratiori panel

B

AR1

14

fop pohnei
Capacitor (Electrolytic)

-P993

10»P iGv+ao7-2o%
Capacitor (Mylar)

O.C047,mF

50V 110%

Capacitor (MylaO
0.047iiF

50V +10%

O.lMF 12V J20*

(C,

TC4G26BP

resistor

1

1/8W lOOK 5*
1

Carbon

remittor

1/8W 1Mohm 5%
Carbon

remittor

ST2BY183J

1/SW 1BK 5%
Carbon

iciiitoi

1/BW 22K 6%
i

-

CaiDon

resistor

1/6W 270
Carbon

ohm 6*

resistor

l/BW 470K

b%

32

*)

Re'

RS

Description

NO.

Location

Carton

resistor

Manjfaclurei
Part Number

ANCM29EB9

VRD-ST2BY564J

AN0Q87EEB

VRD-ST2EY330J

AA2SA733
AA2SC458KS

VS2SA733-/M
VS2SC458KSM

1«VI 550K 5%
Carton
l.'4W

resistor

33 oft m 5%

Transiitor

2SA733

T.arwiitor

7SC453KS

33

EXPLODED V EWr 26-3503;
I

34



File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.5
Linearized                      : Yes
Page Layout                     : TwoPageRight
Page Count                      : 40
XMP Toolkit                     : XMP Core 4.1.1
Metadata Date                   : 2013:05:22 08:33:22Z
Create Date                     : 2013:05:22 08:33:17Z
Modify Date                     : 2013:05:22 08:33:22Z
Creator Tool                    : Digitized by the Internet Archive
Producer                        : Recoded by LuraDocument PDF v2.53
Part                            : 2
Conformance                     : B
Document ID                     : uuid:uuid:de6cc438-56a3-be3f-9816-cafdc84814f6
Version ID                      : 2
Title                           : Radio Shack Hardware Manual: PC-1 Service Manual (19xx)(Tandy)
Creator                         : Digitized by the Internet Archive
Keywords                        : http://archive.org/details/PC-1_Service_Manual_19xx_Tandy