Mitsubishi MF504A-318U Technical Manual

UGD-0344A

5.25

INCH FLEXIBLE DISK
TECHNICAL MANUAL
MF504A-3

DRIVE

AMITSUBISHI

ELECTRIC

CORPORATION

CHAPTER 1

1.1

1.2

CHAPTER 2

2.1

2.2

2.3

2.4

CHAPTER 3

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

3.10

3.11

3.12

CONTENTS

LINE

OUT

Composition of Mechanism by Function

Composition of Electronic Circuitry

MECHANISM

DESCRIPTION

Rotation

Disk

Magnetic H,ad-Positioning

Magnetic Head/Carriage Mechanism . . . . . . . . . . . . . . . . . . .

(Index,

Sensors

DESCRIPTION

Inter.ace and Drive Select Circuits

Power-On Reset and Power

Panel Indicator Circuit .

Sensor

Index

Motor

Step

00

Track

Select

Side

Write/Erase Circuits

Write-Protect Circuit

Circuit

Read

Write Current Switch Circuit . . .

Motor

Spindle

Drive

Write

and

Drive Circuit

Detection

Circuit

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

Drive Circuit

OF

Clamp Mechanism

and

Drive

Protect,

ELECTRONIC

OF

Save

_

...

Ready Circuits

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

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

Circuit

.

.....

..

.

....

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

Track

...

Function

by

OPERATION

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

Mechanism

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

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

00)

CIRCUIT

....

Circuits.

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

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

.

OPERATION

.

.

...........

.

2
2
2

3

4

11
12
13
13

14

1.4

15

5

6
9

9

.

.

.

.

.

16

19
19

22

.

23

-1-

1.

This section deals

flexible
compatible
However,

signal

switched
In

addition,

only

1.1

Composition

The mechani-sm

(1}

(2) Disk

{3)

{4)

(5) Sensors

1.2

Composition

The

The

motor.

( 1)

(21

(3~

(4)

(5)
(6)
(7)

(8}

(9)
(10)
(11)

disk

unit

with

normal

for

360/JOOrpm

at

the

it

is

the

READ/WRITE

of

Lever

mechanism

rotation

Magnetic

Magnetic

{index,

of
electronic
spindle

motor

Signal

interface
Power-on
Panel

indicator

Index

pulse

Step

motor

Track

00

Side select

Write/erase
Write-protect

Read

circuit

Spindle

motor

CHAPTER 1 OUT LINE

with

the

mechanical parts

with

high

density

48TPI

medium

high

and

to

set

the

is

switched.

by

Function
by

funciton as follows:

door

sw

mechanism

mechanism

mechanism

protect,

Circuitry

installed

constitutes

and

drive select

circuit

circuit

circuit

medium

normal

unit

mechanism

track

by

Function

an

two

and

ready

a 8 inch flexible disk allowing

density

for

same

time.

also posible

circuit

mechanitm
can

be

divided

and

and

clamp

head

positioning

head/carriage

write

Electronic

circuits

are

drive

circuit

circuit

reset

circuit
drive

generator

drive

circuit

detection

circuit

circuit

circuit

circuit

drive

and

control

for

the

reading

be

read.

respectively.

circuits

more

can

density

allows

only

for normal density so

00)

printed-circuit

an

independent

circuit

circuit

of

the

than

lMB

and

writing

The

rotational

The

READ/WRITE

that

the

boards

and

printed-circuit

MF504A-3

flexible

formatted

memory

of

previously used normal

speed

can

be

switched

circuitry

disk

rotational speed remains

can

be

classified

which

is

by
built

board

drive.

capacity.

is

also

at

function

integrally

M

F504A-3

It

is

format

density

disks.

by

an

external

automatically

360rpm

as follows:

with

and

the

Screw

Sub Base

bridge

l

Qt

\

Indicator (LED)

Screw

\

Diecast

frame

Figure

2-1

Exploded

-3-

v·

iew

Mechanism

of

/~

L

Knob

ever

y-/

V

Cap

2.1

Oiik

Rotatton

The disk

rotation

because

it

ts

The

motor

does

spindle directly connected
rotation mechanism
300rpm

and this can be swiched by

The

frequency-genentor

The disk

is

to

clamped

•

position

disk

the disk drives.
The

collet

is

Figure 2-2 shows
The printed-circuit
disk

rotation

signal. And a

Collet assmbly

Spindle

Index sensor

(LEO)

Driff

•nd

Cl•mp

MKh•nism

drive

motor

a b<ushtess

not use

is

type

that

ulft

1

belt, unlike C10nventional C10unt1<pwts,

to

uch

is

completely free

coil detects the spindle

by

the

spindle cone

on

the

inner surfoce

tapered

to

• specific

the

spindle

board

detection,

photo

transistor for receiving its light

•ngl•

motor

tor

the

write protect

cone

1

flit

DC

servo

1

othef. This

the

motor.

H1H

element for coil phase-switching

is

onother feature for p<olonging motor life

of

maintenance.

PCA.

NAMFM signals

motor

on

the

motor

of

the

spindle

to

correct non..,lignment

end

collet.

spindle

motor

-vo

sensor LED

for

is

This motor has as

The

rotational speed

trom

speed

1nd

torms

side

and

by

cone.

This assures compotibility

ot

circuit

hH

an

write

protect

installed

on

another printed-circuit

Jong

1

life

11

1n

ordinary

Mtectton.

but

it

1

direct«iw

of

the

the

main control circuit.

•-YO

the

C10llet

circuit
on

the

spindle

an inserted disk with

type

to

C10ntrol

door.

the

~

tpindle

with

Ind

motor

The

the

ouuring

is

360rpm

it.

CIOllet

diskettes

cone.

AC

rotor

thet

guides

index sensor LED (lifht-emitting diode) for

defection and indicator LED

board

for

(NAMFM).

driving

motor

1nd

the
and

the

end

Figure 2·2 Spindle

-4-

Motor

and Collet

Maitnttttc HMd-f'ositioninig

2.2

step

flat

The

step
oppostte

is

distance.

Figure

motor

fastened

2-3

shaft

the

to

shows

motor

steel

the

drives

hm

band

steel

positioning

the

Ori-.ie

magnetic

the

thin~oop

1

m.intain

to

that

so

band

Medt•niMn

head

~nd,

steel

specific

a

turn

a

mechanism.

drive

to

which

of

each

tension.

step

the

track

is

pulled

The

motor

(cylinder)

spring attached

the

by

head/carriage

one

by

succession.

m

assembly,

angle

step

The

1upported

moves

to

the

upstan

idler pulley

the

head

mounted

by

by

two

single

1

guide

the

on

located

rods,

track

Figure 2-3 Magnetic-Head

Step

Positioning

assy

motor

Mechanism

Head/carriage

assembly

-5-

(Index.

Sant0n

2.4

sensor

Index

( 1)

index

The

transistor

photo
motor(Figuro

Index sensor timing (position) can

index sensor.

Figure 2-6 shows where

(2) Writ&-p<Otect sensor

writ&-protect senso<

The

This sensor

with

Disks
sensor.

protect

sub-base,

the

00

Track

(31

track

The

track

The
assembly.
screw.

track

The

Protect.

Writ•

sensor

2-2).

protects

diskette's

the

Remember

disk~

the

this

sensor

sensor

00

sensor

00

sensor

The

sensor

00

Trod< 00)

rotation.

disk

detects

light·recei..,ing side.

the

on

photo

the

ind

photo-transistor for

the

the

detects

information

that

The

stored

covered

notch

or

vinyl

write-protect sensor

will transmit signals

that

detects

the

detects

screwed

is

head/carriage assembly are

and

This sensor consists of

The

mounted

is

tronsistor

adjusted

be

write-protect notch

diskette's

read-only disks from

on

tape

with

to

head

position

the

to

is

PCA.]

is

of

STM.

tape

mounted

on

the

cellophane

the

mounted

ts

LED

the main control

on

the

loosening

by

index: sensor

the

that

,..,

1

or

a high percentage

has

that

sub-base ash shown

on

00

track

light-shielding plate

holder

shown

and

in Figure

can

LED

an

the

on

screws

mounted.

is

inhibits

and

destruction

not

does

that

adjusted in

be

2-7.

hght-emitting

the

on

circuit PCA for

serYO

PCA (NAMFM).

circuit

index

the

on

write

operM:ion

by

litht

transmit

light transmission wilt

of

Figure 2-6.

in

projects

position

seonSOf'

operation.

errors.

protected

1re

the

from

by

and

side

spindle

the

removing

and

by

[Attached

head/carriage

loosening

this

not

to

the

a

Write-protect

Figure 2-6 Index

sensor Disket survey lever

Sensor

Write-protect

and

sensor

-7-

Head/carriage assembly

Figure 2-7 Track

Track

Sensor and Head/Carriage Assembly

00

00

sensor

-8-

3·

ftgure

spindte

TM

integraUy

p.ts

The

CHAPTER

shows

1

motor

with

within

the

the

motor_

the

electrontc

circuit

drive

lines

chain

DESCRIPTION

3

circuits

within

belong

and signal

the

the

to

OF

connections

lines

dotted

mechanism

ELECTRONIC

these circuits.

among

constitutes

the

in

described

CIRCUIT

sepaute

the

previous pages.

OPERATION

printed-circuit

board

that

built

is

-9-

-READ

-WAITE

DATA

DATA

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

I

RIW

IC

M5101

BAP

Read

circuit

Write

ci.-cuit

Er•e

circuit

or

MC2870P

--,

-SIDE·!

-WRITE

-WRITE

-DIRECTION

-NORMAL

-TRACK

-MOTOR

-ORIVE

-ORIVE

-ORIVE

-DRIVE

SELECT

PROTECT

GATE

-INDEX

-READY

IN

SEL

-STEP

DENSITY

00

ON

-IN

USE

SELO
SEL
SEL2
SEL3

Side

select

ci.-cult

Power

on

ruet

circuit

Wri~e

protect

detection

circuit

Write99te

circuit

Erase

gate

circuit

Index

/ready

circuit

Step

motor

drive

ci.-cuit

Track

counter

Track

00

detection

circuit

Head

load

solenoid

drive

circuit

1---1'---4

P•nel

indicator

drive

circuit

Power

1

circuit

511ve

-----------

r,--s:n:.~~;-

~

I

I
I

I

-~

.

I I

~1

~-~,~~c~t--~

Figure

3-1

MF504A-3

-10-

Electronic

Circuit

3-1

lnterf•ce

•nd

11 ~ Receive circuit

AU

the
ohms.
capacity
In

connecting

cabte

(2) Transmit circuit

The

disk

controller

All

input
connected
controller.

(3) Drive select circuit

The

drive select circuit selects

through

The

four

inserted
drives
drives
The

drive select signals also light

In

the

MX

to

Ori••

Select

Circuits

input

terminals

of

the

pulling

them

of

40

mA

or

two

end

four

or

terminating

drive

line driver

to

use a terminating

signals

to

in

the

doisy-chain

interface lines

select lines correspond

to

select

that

will cause errors.

case
maintain

the

are

connected

of

a system requiring no drive selection. insert

a selected condition.

lece1ver

up

to

+5

V.

diik

The

drives

more. Normally.

more

resister and remove

is

an

SN7438N

rnistor

the

line driver are

pattern,

one

of

(OSO

through OS3).

to

the

desired line. Never insert plugs

with

the

same cable; interference between

the

panel indicator LEO.

that

receives

sigNls

from

the

host

con1lloller are

host controlter. therefore. must use driver elements

1n

SN7438N

or

an

equiv•lent

(up

to

fourt

by

the

terminating resistors

or

of

150

ohm1

pted

by

the

signals

the

disk drives Cfour maximum) connected with

jumper

• daisy-chain

equiv1lent open-collector gate. It

or

more.

drive select signals. Thus, if

of

only

one

plugs

on

the

into

open-collector

pattern.

of

the

other

selected disk drive are .transmitted

printedcircuit bOards,

the

same-numbered jacks

the

the

jumper plug for

drive

it

is

necessary

disk drives_

is

necessary for

two

or

more

one

on

output

signals from such disk

the

drive select line

terminated

with

is

recommended.

to

disk drives are

to

the

same cables

of

which should

two

or

a drive

keep

the

the

more

into

at

150

the

host

host

be

disk

the

-11-

3.2

Power-On

(

1)

Power·on reset

The

1or preventing

(2) Power save circuit

The power s1ve circuit
operating
temperature
The
of

30 ms.

Timing

- STEP (TP15)

Anet

•nd

Power

S•we

Circuits

circutt

power-on reset circuit. 1 levet-detection

operation

errors of

the

write

controb

current flowing

to

reduce heat

disk drive.

head load solenoid shore

sove circuit

generllion

is

shown in figure 3-2.

step

condition

motor

chan

rise

of

of
and

the

the

po-

type

reset

drcun.

mitiailizes

the

circuit in switching power

to

the

step

motor

by

unnecessary power consumption

the

same timer (rnono-stablemultivibr1torl, which

and

control

on.

off.

head

load solenoid KCOrding

LSI.

ind

and

thus

that"s used

to

their

to

reduce

has

1 range

\

TRl-collector

output

:~2vv_-:::::::~~~~~~~~~

Figure

3·2

Power Save Circuit Timing Chart

......

~~-:~~~-'f"""""""~.._~~~~~~~~-

l

Jo

ms

,

..

-12

-

3.3

Panel I ndK::1tor

The

panel

indicator

When

no

in-use signal

If

the

jumper

signal

only.

Regarding

Specifications MF504A-3_

3.4

signals.
The

than

When
the

Figure

Index

Sonsor

The index

ready

300

the

ready

J_J

jumper

s.en10r

circuit

ms and

door

signal is

shows

Circuit

plug for

ind

ReMly

circuit

checks

the

opens

reset.

a

timing

is

plug

next

turned

is

the

ind

on

by a drive select signal

applied

to

drive select

combination

Circuits

detects

the

the

index pulse interva1s

index pulse

the

disk

chart_

the

interface,

circuit

is

and indicator

index

holes

is

generated_

stops

rOtating

the

inserted

conditions,

in

with

and

or
panel

the

the

by

into

disk

a

timer,

motor-on

a

dnve

indicator

the

MX,

refer

with

and

select signal

is

turned

the

panel

to

the

detailed

a

sensor,

becomes

signal

turns

and

in-use signal.

on

by

a

drive

indicator

is

description

and converts

ready

when

off

and

turned

its signals

the

the

select signal

on

by

in

the

intervals

disk

stops

only.

an

in-use

Standard

into

logic

are

rotating

less

DOOR

MOTOR

XINDEX

Timer UCG inside)

READY

CLOSE
OPEN

X. INDEX (ICGl-461

Timer

(ICGl

inside)-------'

READY

(ICG1-34J

ON

(Pl-16)

(ICGl-46)

(ICl

·341

Figure

I

.

3-3 Index

JOO

ms

I

. .

.

DOOR

open/closf·

MOTOR

Sensor

on/oft

and

Ready

Circuit Timing

"'-~~~~~~~~

Li

Chart

-13

-

3.5

Step

Motor

Drive

The

step

motor

using

two
These
The

steP

tion

durtng

In

a seek

for

30
Figure 3-4 shows • timing
The

step

seeking

to

prevent

3.6

Track

The

track

assembly, using a sensor. This

signal.
put

is

For a timing

XDSEL flCG1·17J

is

source/sink

four

modes

motor

dritite

times

operation,

ms

or

more, +5 V

mote< drive circuit blocks

during

write

further

00

Detection Circuit

00

detection

The

circuit

on.

chart, refer

Cireutt

a two-phase bipolar

type

drivers.

are

generated

by

circuit

other

outward

will

switches

than

seeking. when

+12 V

is

supplied

is

supplied.

chart.

o-ation.

seek.

circuit detects

not

output

to

figures 3-4.

When

output

type

an

up-down

the

to

the

step

the

the

is

a signal.

the

ANDed with

and

ts

driven

four-court

voltage supplied

the

motor

is

drive

circuit.

pulses

with a write

track

00

sensor

position

of

the

the

therefore,

unless

to a "Step

angle

counter

that

the

motor

if

the

next

gate (except for

turns

the

drive phase is

uses

drive circuit

step pulse

on,

to

still.

but

output

light-shielding plate

step motor drive phase

of

1.8° by feeding four

two

flip-flops.

to

reduce

is

not

the

erase delay time)

the

circuit 1lso blocks

that

projects from

(TKOO)

at

track

00

mode

power

applied

to

the

the

to

generate a track

even if

the

currents,

consump-

the

interface

to

prevent

step

pul-

head/carriage

00

sensor

out-

-DIRECTION
SELECT (TPl-18)

-STEP

(TP151

TKOOIN (TP1)

-WAITE

GATE

(TP6)

STMP1 f!CGl-371

STMP4

llCG1·541

TK

00

iTPl:ll

IN

TO

(INHIBITI

Figure 3-4 Step

TK

I

\J

01

02

I

I

00

I

}TKOO

I

I

I

I

I

I

I

i

I

I

\

' I

\~~

Motor

Drive

Circuit

-14-

02

01

:::i

SENSE\

I

1/

I

When

TKOO

stap

pulses are inhibited

Timing Chart

03

is

enabled,

r-

Step

phase

Same interface
output

outer

moto1

changE>

3.7

Side Select Circuit

Side

selection

is

(H1Bl.

system

ONE

SELECT

made

alternately

is

fed

se•ects

if

This

operation

and

an erase current

bias curTents
and

HOB

The

host

same interface line

Figure 3-5 shows a block diagram

SIDE

by

from

from

it is high.

Figure

switchin9

the head center tap

feeds a write

center tap

CT-0 (CT-11

side

1

~

I

current

CT·O {CT-1) to ER-0 (ER-1)

to

HO'A

(HlAI

through

the

interface

of

the

side

select

!'-----

M51018P

I

I

I
I
I

L_

-

3-5

Side Select Circuit Block Diagram

from

circuit.

or

MC2870P

-

from about 0

center

and

HOB

line

if -

Head

select

driver

--

Vat

off

tap

(HlBI

SIDE ONE

to

CT·O

(CT-11

during write operation.

to

induce a voltage

SELECT

about

to

HOA

ERO

is

0

ER1

11

(HlAI

low,

V

at

between

or

on.

In

side

Side 0

Side 1

and

HOB

(HlBI.

read operation

HOA

(H1B)

0

through

a

the

-15-

Write/Erase

3.8

write circuit is used for recordi™] dat.a

The

~lected

true

The

data

old

l)fevents

thus

write

The

• Write

• Write driver

• R/W

• Write

1

When

operation.

-ite
changes
This differential signal

write driver

The

current

write

R/W

The

write gate.

a

3-6 shows

Figure
Current

figure, according

the

in

operation

Erase

circumferential

point

a
Therefore,

turning

the

to

for

is

It

360rpm

at

kept

be

erase

The

3-8

Figure

Circuiu

diskette

If

head.

enses

circuit

remaining

from

data

old

consists

circuit

flip-flop

to91Jle

matrix

source

current

write gate

is

Write

synchronously

is

source

feeds a

matrix

the

alternately

is

starts

position

R!W

the

that

delay

the

of

on

purpose

this

(approx.

selected.

function

shows

erases

a

~ite·protect

previous

the

either

on

in

crosstalk

following blocks:

the

of

wrtte

the

input,

counted

is

data

write

the

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to

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gap

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shown in figure

operation

erase driver

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300rpm)

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data

conceptual

diagram

stltus

dlt•

of

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toggle flip-flop •

down

data

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the

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generated.

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3

closing

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of

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slight

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for

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voltage

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