Yamaha PS-RS350 Service Manual

SERVICE MANUAL

This document is printed on chlorine free (ECF) paper with soy ink.

PK 001653

■ CONTENTS

SPECIFICATIONS.............................................................................. 3

PANEL LAYOUT ................................................................................. 4

CIRCUIT BOARD LAYOUT & WIRING .............................................. 6

BLOCK DIAGRAM ............................................................................. 8

DISASSEMBLY PROCEDURE .......................................................... 9

LSI PIN DESCRIPTION ................................................................... 13

IC BLOCK DIAGRAM....................................................................... 16

CIRCUIT BOARDS .......................................................................... 16

TEST PROGRAM ............................................................................ 25

DATA BACKUP & INITIALIZATION .................................................. 28

MIDI IMPLEMENTATION CHART .................................................... 29

OVERALL CIRCUIT DIAGRAM
PARTS LIST

1.412K-976 Printed in Japan ’01.05

PSR-350

IMPORTANT NOTICE

This manual has been provided for the use of authorized Yamaha Retailers and their service personnel. It has been assumed
that basic service procedures inherent to the industry, and more specifically Yamaha Products, are already known and
understood by the users, and have therefore not been restated.

WARNING : Failure to follow appropriate service and safety procedures when servicing this product may result in

personal injury, destruction of expensive components and failure of the product to perform as
specified. For these reasons, we advise all Yamaha product owners that all service required should
be performed by an authorized Yamaha Retailer or the appointed service representative.

IMPORTANT : This presentation or sale of this manual to any individual or firm does not constitute authoriza-tion,

certification, recognition of any applicable technical capabilities, or establish a principal-agent
relationship of any form.

The data provided is believ ed to be accurate and applicab le to the unit (s) indicated on the cov er. The research engineering,
and service departments of Yamaha are continually striving to improve Y amaha products. Modifications are , therefor , ine vitable
and changes in specification are subject to change without notice or obligation to retrofit. Should an y discrepancy appear to
exist, please contact the distributor’s Service Division.

WARNING : Static discharges can destroy expensive components. Discharge any static electricity your body

may have accumulated by grounding yourself to the ground bus in the unit (heavy gauge black wires
connect to this bus).

IMPORTANT : Turn the unit OFF during disassembly and par ts replacement. Recheck all work before you apply

power to the unit.

WARNING : CHEMICAL CONTENT NOTICE !

The solder used in the production of this product contains LEAD. In addition, other electrical/electronic and/or plastic
(where applicable) components may also contain traces of chemicals found by the California Health and Welfare Agency
(and possibly other entities) to cause cancer and/or birth defects or other reproductive harm.

DO NOT PLACE SOLDER, ELECTRICAL/ELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH FOR ANY
REASON WHAT SO EVER!

Avoid prolonged, unprotected contact betw een solder and your skin! When soldering, do not inhale solder fumes or expose
eyes to solder/flux vapor!

If you come in contact with solder or components located inside the enclosure of this product, wash your hands before
handling food.

■ WARNING

Components having special characteristics are marked Z and must be replaced with parts having specification equal to
those originally installed.

2

■ SPECIFICATIONS

PSR-350

Keyboards

• 61 standard-size keys (C1 - C6), with Touch Response and
Dynamic Filter.

Display

• Large multi-function LCD display (backlit)

Setup

• STANDBY/ON

• MASTER VOLUME : MIN - MAX

Panel Controls

• OVERALL (L, R), SONG, VOICE, STYLE, PORTABLE
GRAND, DJ, METRONOME, [0]-[9], [+](YES), [-](NO),
DEMO, TOUCH, HARMONY, Dict., L, R, TEMPO/TAP

Voice

• 116 panel voices + 12 drum kits + XG expanded voices +10
DJ voices

• Polyphony : 32

Auto Accompaniment

• 106 styles + Disk

• Accompaniment Control : ACMP ON/OFF, SYNC STOP,

SYNC START, START/STOP,
INTRO/ENDING,
MAINA/B(AUTO FILL)

• Fingering : Multi fingering

• Accompaniment Volume

Music Database

• 208

Yamaha Educational Suite

• Dictionary

• Lesson 1-4

One T ouch Setting

• Voice (for each style or song)

Overall controls

• Lesson R, L

• Octave

• Transpose

• Tuning

• Accompaniment/Song Volume

• Metronome Volume

• Reverb

• DSP

• Harmony

• Grade/Talking

• MIDI

Effects

• Reverb : 8 types

• DSP : 38 types

• Harmony : 26 types

Song

• 100 Songs + 5 User Songs

• Song Clear, Track Clear

Recording

• Song

User Song : 5 Songs
Recording Tracks : 1, 2, 3, 4, 5, CHORD

Disk

• Song Playback

•Save

• Load

• Delete

• Format

MIDI

• Initial Send

• Local on/off

Auxiliary jacks

• PHONES/OUTPUT, DC IN 12V, MIDI IN/OUT, SUSTAIN

Amplifier

• 3.0W + 3.0W

Speakers

• 12cm x 2 + 3cm x 2

Power Consumption

• 22 W (when using PA-5C power adaptor)

Power Supply

• Adaptor : Yamaha PA-5C AC power adaptor

• Batteries : Six “D” size, R20P (LR20) or equivalent batteries

Dimensions (W x D x H)

• 952 x 387 x 169 mm (37-1/2" x 15-1/4" x 6-2/3")

Weight

• 8.5 kg (18 lbs., 12 oz.)

Supplied Accessories

• Music Stand

• Data Disk

• Owner’s Manual

• Song Book

Optional Accessories

• Headphones : HPE-150

• AC power adaptor : PA-5C

• Footswitch : FC4, FC5

• Keyboard stand : L-6

3

PSR-350

■ PANEL LAYOUT

● Top Panel

e

q

w

!8!7 !9 @0 @1 @2

A

r t

i

o

@3

A

y y

000

GrandPno

!0 !2!1

@4 @5

001

@6

u

!4

!3 !5

A’

!6

@7

4

A’

PSR-350

q Power switch ([STANDBY/ON])
w [MASTER VOLUME] dial
e [DEMO] button
r [TOUCH] button
t [HARMONY] button
y Overall (left, right) buttons
u [DUAL] and [SETTING H/G] buttons
i [Dict.] (DICTIONARY) button
o LESSON [L] (Left) and [R] (Right) buttons
!0 [SONG] button
!1 [STYLE] button
!2 [VOICE] button
!3 [PORTABLE GRAND] button

!4 [METRONOME] button
!5 [DJ] button
!6 Numeric keypad, [+/YES] and [-/NO] but-tons
!7 [ACMP ON/OFF] / [A-B REPEAT] button
!8 [SYNC STOP] button
!9 [SYNC START] / [ PAUSE] button
@0 [START/STOP] button
@1 [INTRO/ENDING] / [
@2 [MAIN/AUTO FILL] / [
@3 [TEMPO/TAP] button
@4 [SONG MEMORY] buttons
@5 [MUSIC DATABASE] button
@6 [REGISTRATION MEMORY] buttons
@7 Disk Drive

REW] button

FF] button

● Rear Panel

@8 [MIDI IN], [MIDI OUT] connectors
@9 [FOOT SWITCH] jack

@9@8 #0 #1

#0 [PHONES/OUTPUT] jack
#1 [DC IN 12V] jack

5

PSR-350

■ CIRCUIT BOARD LAYOUT & WIRING

● Lower case side

Speaker (Woofer-R)

● Upper case side

-R

TW

[450]

[PN-WH2]

[WH200]

DM

[PN-WH1]

[AM-WH3]

[460]

[C40]

[AM-WH2]

AM

Speaker (Woofer-L)

[C50]

[PN-WH10]

TW

-L

Speaker (Tweeter-R) Speaker (Tweeter-L)

TW

Speaker (Tweeter-R) Speaker (Tweeter-L)

MK-H

-R

[450] [460] [AM-WH2] [AM-WH3] [AM-WH7] [PN-WH10]

[PN-WH9]

FDD

[AM-WH999] [AM-WH998]

[440]

[L70]

AM

MKS5

[PN-WH11][L70]

[PN-WH11]

MK-L

TW

-L

6

● Upper case side

PSR-350

LCD

[WH200] [L70]

PN1

[PN-WH2] [PN-WH1]

PN2

[PN-WH4]

Back Light Assembly

[PN-WH6]

[PN-WH5]

PN4 PW VR

[PN-WH10]

[PN-WH9]

[PN-WH11]

PN3

Location Part No. Connector Assembly Destination Remarks

440 - - KB DM-CN102 *6 *1 MKS5-CN1 *6 *1 6P (V718860)
450 V3819800 FDD DM-CN301 *1 FDD-CN1 *3 34P
460 - - FDPS AM-CN908 *1 FDD-CN2 *2 2/4P (V718900)
C40 - - SP Speaker (Wo) AM-CN802 *4 4P (V718870)
C50 - - BAT Battery AM-CN903 *5 2P (V705790)
AM-WH2 - - PS AM-CN901 DM-CN101 *1 7P (V718820)
AM-WH3 - - DJ AM-CN602 DM-CN601 *1 6P (V718830)
AM-WH7 - - EP1 AM-EP1 AM-EP2 L=120 (V719460)
AM-WH998
AM-WH999

- - TW AM-CN909 TW-L (V718880)

- - TW AM-CN910 TW-R (V718880)
WH200 - - LCD LCD-CN1 DM-CN175 *1 12P (V718800)
PN-WH1 - - PN1 PN 1-CN1 DM-CN701 *1 8P (V718750)
PN-WH2 - - PN2 PN 1-CN2 DM-CN702 *1 10P (V718760)
PN-WH4 - - PN3 PN 2-CN4 PN 1-CN3 *1 15P (V718770)
PN-WH5 - - PN4 PN 2-CN5 PN 4-CN8 *1 7P (V718780)
PN-WH6 - - PN5 PN 2-CN6 PN 3-CN7 6P (V718790)
PN-WH9 - - VR1 VR-CN9 DM-CN501 *1 5P (V718840)
PN-WH10 - - VR2 VR-CN10 AM-CN801 *1 5P (V718850)
PN-WH11 - - SW PW-CN11 AM-CN902 *1 4P (V719860)
L70 - - BLT Back Light AM-CN907 *1 2P (V718810)

* The parts with “–” in “Part No.” are not available as spare parts.
* 1 : Edge mark is adjusted to Pin 1 mark ( mark).
* 2 : Red wire is adjusted to Pin 1 mark (
* 3 : Connector hook is located at the upper side of FDD.
* 4 : White wire is adjusted to Pin 1 mark (
* 5 : Red wire is adjusted to Pin 1 mark (
* 6 : Be sure to make a correct match when connecting MKS5(CN1) and DM(CN102).
Connecting the connectors in the wrong way around may cause damage to the MKS5 circuit board.

mark).

mark).

mark).

Caution: Be sure to attach the removed filament tape just as it was before removal.

7

8

5MHz

CN3

CN2

CN4

CN1

BACK LIGHT

CN301

CN102

CN702

CN701

CN1

CN2

CN3

CN4

CN5

CN6

CN7

CN01

CN101

CN902

CN903

32M

32M

SWX00B

CN602

CN601

IC601

CN715

1

CN9 CN10

VR1

MASTER
VOLUME

CN801

CN909

CN802

CN910

LA4705NA

14

15

NJM78L05A

CN901

CN907 CN908

CN11

CN8

TWEETER

WOOFER

TWEETER

WOOFER

28CA1-889533

MKS5

MK-L MK-H

PN1

PN2

PN4

PN3

LCD

AM

VR

PW

TW -R

TW -L

PSR-350

■ BLOCK DIAGRAM

■ DISASSEMBLY PROCEDURE

1. Lower Case Assembly

(Time required : About 5 min.)

1-1. Remove the fourteen (14) screws marked [270A] and the four (4) scr ews marked [280A].

The lower case assembly can then be removed. (Fig. 1)

PSR-350

[270A] [270A] [270A]

[280A] [280A]

[270A]

[270A] :Bind Head Tapping Screw-P 3.0X12 MFZN2Y (EP600300)
[280A] :Bind Head Tapping Screw-P 3.0X25 MFZN2Y (VK228100)

2. Spring T erminal

(Time required : About 10 min.)

2-1. Remove the lower case assembly.
2-2. Remove the BAT connector assembly (red/black)

soldered to the spring terminal (+)/(-). (Fig. 2)
2-3. Remove the battery cover assembly. (Fig. 1)
2-4. Remove the spring terminal by releasing hooks (2

locations for each). (Fig. 3)

BAT Connector
Assembly (Black)

Lower Case Assembly

(Fig. 2)

(See procedure 1)

BAT Connector
Assembly (Red)

[270A]

(Fig. 1)

Lower Case AssemblyBattery Cover Assembly

[270A]

3. DM Circuit Board, Shield Box U and L

(Time required : About 10 min.)

3-1. Remove the lower case assembly.

(See procedure 1)

3-2. Remove the two (2) screws marked [270B] and

the thirteen (13) screws marked [290]. The shield
box U and the DM circuit board can then be
removed. (Fig. 4)

3-3. Remove the three (3) screws marked [260A]. The

shield box L can then be removed. (Fig. 4)

4. Floppy Disk Drive Assembly

(Time required : About 10 min.)

4-1. Remove the lower case assembly.
4-2. Remove the DM circuit board and the shield box

U and L. (See procedure 3)

4-3. Remove the four (4) screws marked [300]. The

floppy disk assembly can then be removed. (Fig. 5)

(See procedure 1)

Hook

(Fig. 3)

Hook

Spring Terminal

5. AM Circuit Board

(Time required : About 10 min.)

5-1. Remove the lower case assembly.
5-2. Remove the seven (7) scre ws mar ked [260B]. The

AM circuit board can then be removed. (Fig. 5)

(See procedure 1)

9

PSR-350

[C30]

Speaker (Woofer) Speaker (Woofer)

Shield Box U

[290]

Shield Box L

[290] [290] [290]

[260A]

[30]

[C30]

[C30][C30]

[280B]

AM

[270B]

DM

[280B]

Speaker (Tweeter)

[260J]

[290]

[290] [290]

[30] : Bind Head Tapping Screw-P 3.0X8 MFZN2Y (EP600280)
[260A] :Bind Head Tapping Screw-P 3.0X8 MFZN2Y (EP600280)
[270B] :Bind Head Tapping Screw-P 3.0X12 MFZN2Y (EP600300)
[280B] :Bind Head Tapping Screw-P 3.0X25 MFZN2Y (VK228100)
[290] : Bind Head Tapping Screw-B 3.0X8 MFZN2Y (EP600250)
[C30] : Bind Head Tapping Screw-P 4.0X8 MFZN2BL (VB931600)

Keyboard
Assembly

[270B]

(Fig. 4)

-R

[300]

[260B]

AM

FDD

[260B][300]

[260B]

MK-LMK-H MKS5

-LTW

TW

Speaker (Tweeter)

[260J]

10

[260] : Bind Head Tapping Screw-P 3.0X8 MFZN2Y (EP600280)
[300] : Sems Pan Head Screw 3.0X10 MFZN2Y (V5115200)

(Fig. 5)

PSR-350

6. PN 1 Circuit Board

(Time required : About 15 min.)

6-1. Remove the lower case assembly.

(See procedure 1)

6-2. Remove the DM circuit board and the shield box

U and L. (See procedure 3)
6-3. Remove the floppy disk drive assembly. (See

procedure 4)
6-4. Remove the six (6) screws marked [260C]. The

PN 1 circuit board can then be removed. (Fig. 6)

7. PN 2 Circuit Board

(Time required : About 20 min.)

7-1. Remove the lower case assembly.

(See procedure 1)

7-2. Remove the DM circuit board and the shield box

U and L. (See procedure 3)
7-3. Remove the floppy disk drive assembly. (See

procedure 4)
7-4. Remove the AM circuit board. (See procedure 5)
7-5. Remove the ten (10) screws marked [260D]. The

PN 2 circuit board can then be removed. (Fig. 6)

8. PN 3 Circuit Board

(Time required : About 8 min.)

8-1. Remove the lower case assembly.

(See procedure 1)

8-2. Remove the six (6) screws marked [260E]. The

PN 3 circuit board can then be removed. (Fig. 6)

9. PN 4 Circuit Board

(Time required : About 10 min.)

9-1. Remove the lower case assembly.
9-2. Remove the AM circuit board. (See procedure 5)
9-3. Remove the four (4) screws marked [260F]. The

PN 4 circuit board can then be removed. (Fig. 6)

(See procedure 1)

10. PW Circuit Board

(Time required : About 5 min.)

10-1. Remove the lower case assemb ly.

(See procedure 1)

10-2. Remove the two (2) screws marked [260G]. The

PW circuit board can then be removed. (Fig. 6)

11. VR Circuit Board

(Time required : About 10 min.)

11-1. Remove the lower case assemb ly.
11-2. Remove the AM circuit board. (See procedure 5)
11-3. Remove the volume knob from the control panel

side. (Fig. 7)

11-4. Remove the three (3) scre ws mark ed [260H]. The

VR circuit board can then be removed. (Fig. 6)

Volume Knob

(Fig. 7)

12. LCD Unit (LCD Circuit Board, Back Light
Assembly and LCD)

(Time required : About 20 min.)

12-1.

Remove the lower case assembly. (See procedure 1)

12-2. Remove the DM circuit board and the shield box

U and L. (See procedure 3)
12-3. Remove the AM circuit board. (See procedure 5)
12-4. Remove the four (4) screws marked [260I]. The

LCD unit can then be removed. (Fig. 6)
12-5. Remove the eight (8) screws marked [L50]. The

LCD circuit board can then be removed. (Fig. 6)

(See procedure 1)

[260F]x4

PN1

[260C]x6

[260] : Bind Head Tapping Screw-P 3.0X8 MFZN2Y (EP600280)
[L50] : Bind Head Tapping Screw-P 3.0X8 MFZN2Y (EP600280)

[260I]x4

[L50]x8

PN2 PN3

[260D]x10

LCD Unit

(Fig. 6)

[260G]x2

[260E]x6

[260H]x3

*

When you install the LCD circuit board, tighten the screws

from No.1 to No. 8 in order as shown in Figure 6-1.

VRPWPN4LCD

3456

LCD

1782

(Fig. 6-1)

11

PSR-350

13. Keyboard Assembly

(Time required : About 10 min.)

13-1. Remove the lo wer case assembly.

(See procedure 1)

13-2. Remove the two (2) screws marked [280B]. The

keyboard assembly can then be removed. (Fig. 4)

14. Speakers and TW Circuit Board

(Time required : About 10 min.)

14-1. Remove the lo wer case assembly.

(See procedure 1)

14-2. Remove the right and left (woofer) speakers by

removing four (4) screws marked [C30] from each
speaker. (Fig. 4)

14-3.

Remove the right and left TW circuit boards by
removing two (2) screws each mark ed [260J]. (Fig. 5)

14-4.

Remove the right and left (tweeter) speakers. (Fig. 5,
Photo 1)

TW

Sponge

Speaker (Tweeter)

(Photo 1)

15. Disassembling the Keyboard Assembly

15-1 Remove the keyboard assembly .
15-2 Remove the two (2) screws marked [30]. The

MKS5 circuit board can then be removed. (Fig. 4)

15-3 Remove the MK-L and MK-H circuit boards while

pressing the fifteen (15) hooks A inward, and then
remove the rubber contact. (Fig. 8)

15-4 Remove the twenty-one (21) screws marked [140],

then remove the black keys from the lower notes.
Afterwards, remove the white keys DFA and C'
and then remove the white keys CEGB from the
higher notes. At this time, lift the keys from the
front and slide them towards you. the ke ys can then
be removed from the assembly. (Fig. 9)

MK-L , MK-H

Hooks A

(See procedure 13.)

White Key

[140]

Black Key

White Key
DFA

White Key
CEGB

[140] : Bind Head Tapping Screw-P 3.0X16 MFZN2Y (EP600310)

Black Key

(Fig.9)

[140]

White Key C’

16. Assembling the Keyboard Assembly

16-1 Install the white keys CEGB from the lower notes,

and then install the DFA keys and C' key.
Afterwards install the black keys from the higher
notes, and tighten the twenty-one (21) screws
marked [140]. (Fig. 9)

16-2 Install the rubber contacts in the assembly while

pressing the keys as shown in Figure 10. Check
that the rubber contact has been firmly placed into
position in the area indicated by the arrow in Figure 11.
When fitting the rubber contacts, raise both ends
of the frame so that keys do not push the rubber
contact up.

16-3 I ns tal l th e MK -L , MK -H c irc uit bo ard s in the

assembly so that the hooks B hold it as shown in
Figure 12.

Rubber Contact

(Fig.10)

Rubber Contact

(Fig.11)

MK-L , MK-H

Hooks B

12

Black Key

Rubber Contact

(Fig.8)

(Fig.12)

■ LSI PIN DESCRIPTION

PIN
NO.

I/O FUNCTIONNAME

PIN
NO.

I/O FUNCTIONNAME

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18
19
20
21
22

P12
P11
P10
P47/KR7
P46/KR6
P45/KR5
P44/KR4
P43/KR3
P42/KR2
P41/KR1
P40/KR0
NC
IC
X2
X1
VSS0
VDD0
/RESET
P53
P52
P51/TO2
P50/TI0/TO0

I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O

I

I
I/O
I/O
I/O
I/O

Port 1

Port 4/Key return signal detection input

Internally connected (N.C.)
Clock
Ground

Power supply
System reset

Port 5
Port 5/16-bit timer output

Port 5/External count clock input to 8-bit timer/8-bit timer output

23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44

P32/INTP2/CPT2
P31/INTP1
P30/INTP0
P22/RXD/SI0
P21/TXD/SO0
P20/ASCK//SCK0
P07
P06
P05
P04
P03
P02
P01
P00
NC
VDD1
VSS1
P17
P16
P15
P14
P13

I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O

I/O
I/O
I/O
I/O
I/O

Port 3/External interrupt input/Capture edge input
Port 3/External interrupt input
Port 2/Asynchronous serial interface serial data input/Serial interface serial data input

Port 2/Asynchronous serial interface serial data output/Serial interface serial data output
Port 2/Asynchronous serial interface serial clock input/Serial interface serial clock

Port 0

Power supply
Ground

Port 1

µPD789022GB-A15-8E (XZ560100) CPU........................................................................................... 13

HG73C205AFD (XU947C00) SWX00B (Tone Generator)................................................................... 14

HD63266F (XI939A00) FDC (Floppy Disk Controller) ......................................................................... 13

S6A0069X10-Q0RJ (XV226A00) LCD DRIVER.................................................................................. 15

PSR-350

● µPD789022GB-A15-8E (XZ560100) CPU

● HD63266F (XI939A00) FDC (Floppy Disk Controller)

PIN

NAME

NO.

1

8"//5"
XTALSET

2

/RESET

3

E//RD

4

RW//WR

5

/CS

6

/DACK

7

RS0

8

RS1

9

VSS1

10

VSS2

11

D0

12

D1

13

D2

14

D3

15

D4

16

D5

17

D6

18

D7

19

/DREQ

20

/IRQ

21

/DEND

22

VSS3

23

1/2 EX1

24

VCC1

25

NUM1

26

NUM3

27

IFS

28

SFORM

29

/INP

30

/READY

31

/WPRT

32

I/O

I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O

O
O

I
I
I
I
I
I
I
I
I

I

I
I
I
I
I
I
I

Data transmission speed
Clock select
Rest
Enable/Read
Read/write/Write
Chip select
DMA acknowledge

Register select
Ground

Data bus

DMA request
Interrupt request
Data end
Ground

Power supply

Host interface select
Format data
Index pulse
Ready from FDD
Write control signal

FUNCTION

MKS5 : IC1

DM : IC304

PIN

NAME

NO.

33

/TRKO

34

/INDEX

35

/RDATA

36

XTAL2

37

EXTAL2

38

NC

39

XTAL1

40

EXTAL1

41

VSS4

42

VSS5

43

NC

44

VCC2

45

VCC3

46

VCC4
/WGATE

47

/WDATA

48

VSS6

49

/STEP

50

/HDIR

51

/HLOAD

52

/HSEL

53

VSS7

54

/DS0

55

/DS1

56

/DS2

57

/DS3

58

VSS8

59

/MON0

60

/MON1

61

/MON2

62

/MON3

63

VSS9

64

I/O

O
O

O
O
O
O

O
O
O
O

O
O
O
O

I
I
I

Track 00 signal
Index signal
Read data input from FDD

Clock

Clock
Ground

Power supply
Write control

Writ data to FDD
Ground
Step signal to control head of FDD
Direction
Head load
Head select
Ground

Drive select

Ground
Motor on

Ground

FUNCTION

13