Casio DR-120XA Troubleshooting guide

(without price)

DR-120XA (LX-224C/D)

DL-220BAGY(LX-224I)

DR-320A (LX-224B)

SEP. 1995

DR-120XA

INDEX

CONTENTS

1. SPECIFICATIONS ......................................................................................................... 1

2. BLOCK DIAGRAM ........................................................................................................ 1

3. CPU (MN15418YCY) PIN FUNCTION........................................................................... 2

4. DIAGNOSTIC................................................................................................................. 3

5. TROUBLESHOOTING................................................................................................... 4

6. DISASSEMBLY VIEW ................................................................................................... 5

7. SCHEMATIC DIAGRAM................................................................................................ 6

8. PARTS LIST ................................................................................................................ 10

— 1 —

Display tube

FG138AW7

CPU

MN158418YCY

Power supply

circuit

Slide switch

Keyboard

Printer

M-80

VF1,VF2

Ribbon shift signal

Character selective signal

Timing pulse

Digital signal

D1~D13

Motor control signal

VDD, VSS

Sent signal

S1~S7, SAP, SDP

SO1~SO7

SI1~SI3, SI5

KO1 ~ KO8

KI1 ~ KI6

VIM, VDD

1. SPECIFICATIONS

Roll paper size : Width: 57 ~ 58 mm

Ink ribbon : Red/Black: RB-02

Green/Black: GB-02

Power source : AC 100, 120, 220 or 240 (±10 V), 50/60 Hz

• Refer to the operation manual for other specifications.

2. BLOCK DIAGRAM

— 2 —

Pin No. Signal I/O Function

1~7, 64 P00~P13 Out Common signal for keyboard

8~12 P20~P22, P32, P33 In Key signal from keyboard

13 IRQ In Timing pulse signal from printer

14 DEBIN In Reset pulse (Not used)

15 IRQCNT In Auxiliary timing (VDD)

16 P40 Out Motor control signal

17 P41 Out Ribbon shift signal for printer

18~30 P42, P43, P50~P53, Out Character selective signal for printer

P70~P73, P80~P82

31, 32 P83, P90 Out Segment signal for display,

Character selective signal for printer

33~39 P91~P93 Out Common signal for slide switch,

PA0~PA3 Segment signal for display

40 P60 In Input port (VDD)

41~43 P61~P63 In Signal from slide switch

44~56 PB0~PB3, Out Digit signal for display

PC0~PC3,

PD0~PD3,

PE0

57 VPP In GND terminal

58 VDD In VDD terminal (+33V)

59, 60 OSC1, OSC2 I/O Clock signal for CPU

61 VSS In VSS terminal (+28V)

62 SYNC — Not used

63 RST In Signal from slide switch, Reset signal

3. CPU (MN158418YCY) PIN FUNCTION

— 3 —

OPERATION

1 00 TM

8 – ÷9 % ◊/#

• 1 2 3 4 5 6 7

M+

M–

÷5 MU/MD

M◊

M❊

CA 1 ÷ ÷ 1 M

X 1 – 1 –

◊/#

–

❊

G❊

FEED

M❊AC

1 • =

0 • 01M+

0 • 01 X

[- 1 • =]

[- 0 • 01 +]

[0 • 01-]

[- 0 • 02 ◊]

002

[- 0 • 02◊]

[-0 • 01-]

001

[- 0 • 03 G❊]

001

[- 0 • 03 G❊]

Paper feeding

001 0 • 01M❊

• • 0 • •

NOTE

The character with

"[ ]" will be printed

by red ink.

Press the button 2

or 3 seconds

continuously.

STEP

4. DIAGNOSTICS

MODE SWITCHES

ON F 6

ON CUT 6

ON CUT 4

ON UP 3

ON 5/4 2

ON 5/4 1

ON 5/4 0

ON 5/4 ADDX

PRINT 5/4 ADDX

PRINT 5/4 ADD+

ITEM+ 5/4 ADD+

ITEM+/– 5/4 ADD+

▲

DISPLAY

100°0.

-88.8888888888

-88.888888888

0.1234567

M 0.123456

M 0.1234

M 0.124

M 0.12

M 0.1

M 0.

M 0.123

0.123

M 0.01'

M -0.02

M -0.03

M 001

M -0.03

[-]

[88.8888888888]

• • 0 • •

1 • ÷

1 • K÷

0 • 01 ÷

— 4 —

1) Does not work

at all.

2) No display.

3) No print.

4) Poor display.

5) Poor printing

• Motor does

not stop.

• Missing of

digits. •Refer to the printer service manual published separately.

VDD, VSS, VM, VF1, and

VF2 are OK?

Check the pulse signals

from LSI.

If VF1, VF2, Digit and

Segment signals are OK.

VM=17V (while printing)

Check detector of printer

block and timing signal.

Secondary voltage

of transformer

Waveforms of each

VF1, VF2

Signal D1 ~

S1 ~

Between LSI and

display tube

Trouble Cause Checkpoint Note

5. TROUBLESHOOTING

•Defective power transformer

•Defective LSI

•No voltage at VF1, VF2

•No digit signal or no segment

signal

•Defective display tube

•Poor voltage VM

•Defective motor

•Defective LSI

•Short or open circuits between

digit signals and segment sig-

nals.

•Defective display tube

•Timing signal is bad.

•Defective printer magnet

— 5 —

6. DISASSEMBLY VIEW

Power Cord

Projection side

Black

Projection side

Marking side

Brown

Blue

Brown

Blue

Transformer

Yellow

Black

Blue

Black

White

Black

Red

Connection

Voltage

100V

120V

220V

240V

— 6 —

7. SCHEMATIC DIAGRAM

7-1. Main board

— 7 —

7-2. Keyboard

KO1

KO2

KO3

KO4

KO5

KO6

KO7

KO8

FEED

–

MU/MD

M+

/ #

M–

TIME

000

KI1

KI2

KI3

KI4

KI5

KI6

— 8 —

7-3. Slide Switch Board

OFF

PON

IT+

IT–

CUT

5/4

ADDX

ADD+

SO1

SO2

SO3

SO4

SO5

SO6

SO7

VSS SI5

SI3

SI2

SI1

MODE SWITCH

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