Hitachi HMA-6500 Service manual

SERUICE

SPECIFICATIONS

MATUA1

English

Deutsch Franqais

No.

159

Continuous RMS

output)

(lHF)

output)

j

(

mpedance)

ratio

(both

Harmonic d istortion

(at

rated output)

rated

1

12

lat

Power bandwidth

(at

rated

1

l2

Frequency characteristics

(at

1 W output)

I

nput

sensitivity

(lHF,

A

supply

consumpllon

factor

separation

network)

impedance

Damping Channel Slgnal-to-noise

Speaker Power

Power

Dimensio ns

Weight

power

outpul

channels driven)

50

watts

20 Hz Io

harmonic

w/ch

than than

(SO

(1

kHz,

dB

ohms

120

(W)

kg

kohms)

(1

V

or

(-

(wl

(20.7

+

kHz

KHZ

kHz, 8 ohms,

320 VA

x 153

55

53 w/ch

Less

5 Hz-60

DC-1OO

5Nz-100

1 V

50

80 dB

115

4-16

AC

22OW

430 W 435

11-118

9.4

per

channel

min.

RMS,

at 8 ohms from

20 kHz, with no more than 0.02% total

distortion.

(8

ohms, T. H.

1? dB

(A,

B), 8-16

-

(H)

lbs

)

(8

ohms,

(4

ohms,

(DIRECT

(CONDENSER

input shorted)

ohms

v

120

x

120 V)

306

l22O

(D)

(AC

1 kHz, T.H.D 1

kHz, T.H.D

D. 0.05%)

COUPLING)

COUpLtNG)

(A+B)

V

v

1240

mm

Dl

O.O2%l

.

.0.02%l

50/60 Hz

55 w/ch 53 w/ch

0.02%

0.003%

kHz 1? dB

8 ohms)

60 Hz,

220-240V1

x 6-1132 x 12-1116

Specif ications

and

designs may

STEREO

be changed

wlthout

notice

POWER

Febru

ary

for

improvement

AIhPI.ITIER

I

979

t

Sinusdauerleistung

Klirrfaktor

(bei

(óei

Leistungsbandbreite

(bei

Frequenzgang

Eingangsempf

(

I mpedanz)

Dampf

Kana

Geràu

(lHF,

Lautsprecherim

Netzspan

Leistu ngsauf

Abmessu ngen

Gewicht

Anderungen der

(beide

Nennlelstung)

1

NennleistÙng)

12

112 Nennleistung)

(bei

lich

ind

aktor

u ngsf

ltrennung

nu

ngsabsta

pedanz

ng

nahme

technischen

schspannu

A-Netz)

(

MS)

R

Kanàle

(

I HF)

1

Watt)

keit

betrieben)

nd

Daten

bleiben

SOWKanal

Gesamtkl irrfaktor

55 W/Kanal

WlKanal

53

Wen iger als O

Weniger als 0,003%

Hz

5

Gleichstrom-l00

5 Hz

1 V

50

{1

80 dB

*'SOWlKanal

+

,02o/o

kHz

60

-

100 kHz l?

-

(50

kOhm)

kHz, 8 Ohm)

(1

kHz,8

0,02%)

W/Kanal

55 53

W/Kanal

(8

Ohm, Gesamtklirrfaktor 0,05%)

kHz 1Î Oa

d

Ohm,

1l5dB

(-220

x 153

(A,

120

320

-

VA

240

(H)

B),

V

x

4

16Ohm

-

Wechselstrom

22OW oder

430W

(B)

435

ks

9,4

im Sinne der stàndigen

(g

(

Kapazitive

B

Eingang

16Ohm

8

-

Ohrn;20

(8

Ohm,.1

(+

Ohm,"'!.

(Oiret<tkopplung)

Hz

-20

Gesamtklirrfaktor

kHz, kHz, Gesamtktirrfaktor

Kopplung)

kurzgeschlossen)

(A+

B)

60H2,-12OVl22OVl24O

20 V Wechselstrom)

f

Vl

(T)

306

mm

Verbesserung

vorbehalten.

kHz,

V 50i60

O

O,O2%l

Hz

'O2%l

SPECIFICATIONS

Pu

issance

effective continue

puissance

la

puissance

f

de

réq

sortie 1

(

impedance)

/bru

A)

(avec

uence

W)

it

Distorsion

(à (à

harmonique

puissance

la moitié

sortie nominale)

passante

Bande

(à

la moitié de la

nominale)

sortie

Caractéristiques

(à

puissance

Sensibi lité Coeff icient

Séparation

Rapport

(lH

lmpédance

d'entrée

d'a

de canal

signal

F, Réseau

d'enceinte

Alimentation

Consommation

Dimensions

Poids

de sortie nominale)

de

(lHF)

de

mortissement

sígnal

d'énergie

les deux

de

canaux)

50

w/ch

55 w/ch 53 w/ch

lnférieure

lnf

érieure

5 Hz

-

CC_lOO

Hz-100

5

(50

V

1

(1

50

kHz,8

(1

80

dB

115d8

4-1

6 ohms

CA

1

20

22OW

ou

(-220-24OVl

430W

(L)

435 9,4 ks

+

50 w/ch

+

55 w/ch

+

53 w/ch

à

0,02%

à

0,003%

60 kHz

KHZ

kHz

kohms)

ohms)

kHz,8

(A,B),

V

6O

320 VA

'153

x

(8

ohms,

(8

ohms, 1 kHz, D.H.T.

(4

ohms,

(8

ohms, D.H.T.

(COUPLAGE-DIRECT)

dB

1?

(coupLAGE

l? dB

ohms, entrée

8-16 ohms

Hz,

12O V

3OO

1220

120 V)

(P)

(H)

-

(CA

x

Nz

20

1 kHz,

0,05%)

court

(A+B)

V

mm

20 k1z,

-

D.H.T.

pAR

circuitée)

l24O

H.T.

D.

O,O2%"1

O,02"/"1

O,O2y"l

CONDENSATEUR)

v

50/60 Hz

ît

l

I

i

I

Les caractéristiques

techniques

présentation

et

a

peuvent

étre

.,

modif iées

sans

préavis

en

raison

d'améliorations.

l

I

i

I

DISASSEMBLY

DEMONTAGE

^

o

Removing the

.

Ausbau

o

Déposer

cover,

Abdeckung, der Schildanbringung

der

le

supérieur,

AND REPLACEMENT.

ET

escutcheon

le cache-entrée

REMONTAGE

ass'y

ZERLEGUNG

The numbers

respond

ZifÍern

Die

entsprechen denen

numéros encerclés

Les

ceux de

à

in the

to those

in the

den Kreismarkierungen

in

in der

la liste de

I

@

I

pièces

,sPxeor@l

UND

circle marks

replacement

Ersatzteilliste.

le

sur

de remplacement,

AUSTAUSCH.

in the diagram cor-

parts

list.

Diagramms

des

schéma

correspondent

2

o

Removing the

o

Ausbau der

o

Déposer

POWER Leisîun

Tronsisîor

POWER MOS

Leistungs - MOS

le

transistor

MOS

FET(x4)

gs-MOS

3Éx16

ò

-FET(x

effet

(xB)

FET

à effet de

de

chomp(x4)

-

champ

4

)

FET

fo

.3cx6or

(xz)

@

Fig. I Abb.

Fig.2

Abb.2

I

3Éx8DT(x.,@ì

-3-

HITACHI HMA.6500

o

Removing the

printed

Powen

boards

wiring

supply

o

(A

Stromqúíb

Alimentoîion

Ausbau

der Leitterplatten

3q6Dr

úeor

t

3 I

O

o

^

(O

frloin

omp

Houptversîórker

Amplif

icoteur

5q

Déposer

@

'Woshcr

_kl) @

plaquettes

des

principo

à circuit imprimé

I

î.

SERVICE

o

As this unit uses a

careful

repairing.

(1)

To check

to cut off the

Discharge

a resistor positions

When

discharging through the chassis

danger that

mixed, in this

the

(2)

.

@ not

Do

voltmeter

current as malfunction may meter carefully.

driver.

Parts installation method

Great

care

safety of

tubes,

or they are

board surface. Be sure

tions after DIRECT

this is

Since

in equipment

occurs

amplified

deterioration

POINTS

the following

of

repair

and

power

the

approx.

of

C803

and C804.

Rl or R2 may

case, so be

andQ terminals

touch the terminals

when connecting it for

is

taken

products.

replacing

COUPLING/CONDENSER

a DC amplifier,

and

a DC bias

tone

of

large capacity

points

printed

the

pull

and

capacitors by

10 ohms, 5 watts

be

sure

the electrolytic capacitor.

of

result. Handle the DC volt-

Wind insulating tape around the screw-

installing

in

example,

For

kept away from the

maintain

to

parts

for repair.

when

connected

placed

is

quality

and

power

supply,

checking

when

boards,

wiring

out the

power

touching it

capacity at the

ground,

open and noise becomes

bé sure

cord.

there is

to discharge between

nearby

parts

with a DC

adjusting the idle

parts

to improve

parts

are covered

printed

COUPLING

direct current

to the input, it

the

to

speaker

generation

of distor-

wiring

condi

switch

leakage

will be

causing

be

and

with

the

with

Fig. 3

Abb.3

tion : this switch This al.so

because

damage

noise

change

of trouble in the control amplifier

the speaker. If there

("puu

to

prevents

is heard when turning

...")

CONDENSER COUPLING at that time.

this.

the flow of a large DC component

which would

if

leakage in the input,

DC

switch, so

this

oRl

ground

The

the unit are connected

in Fig. 4.

c

is

The

case, and in order to

and the radiation fan, stability deteriorates by this, so

the FET is isolated

47

ohms.

Accordingly, be careful

ing

the

charge the

this may

nolse.

of

round

orR

because the

lead

Q

electrolytic

cut

the

the signal

lr.

wire of

lead wire of

line and

using Rl

POWER MOS FET is

maintain the capacity between FET

from

the chassis

not to cause an

the speaker to the

capacitor during servicing,

the

(47

v>

ground

Chassis

using

or R2 and introduce

Rl

ground

chassis

ohms) as shown

in the source

a resistor

by

output

chassis or dis-

Fig.4

touch-

since

of

î

a

î

-4-

HITACHI HMA-6500

.

Precautions on

(1)

When parts

of

peripheral

input/output DC input/output/

(2)

Since

@

-

ing

the

(3)

Since

socket of the

as B, C,

when replacing

checking.

.

Gautions

(1)

Oscillations

troubleshooting

stabilized

the

and

Q701

parts)

are replaced,

may

voltage.

DC

grade of hrs is specially

@

@fo.

proper grade

the

E. Match it to the

Q701

socket

POWER MOS FET,

the

checking

on

may occur depending

ADJUSTMENT

.

Adjusting idle current Perform

switch turned OFF.

Remove the wiring

the

FET

Next,adjust R75 lL and

so that

Attached

ment is completed.

adjustment with

of the DC

side

@

and the

are both 150mA.

they

the

wiring

@

O

parts

the

peripheral

power

Q702

and replacing

circuit

(D106,

and

R752, R753 and

the adjustment of the

so be sure to check the

drift,

classified into

and

the

with

for

transistor

POWER MOS

voltage

the

replace

Q702,

proper

use

polarity

indications shown in

them

channel.

used

is

FET

is

indicated

and when

on the voltmeter

no signal and with the speaker

shown in Fig. 6 and connect

,

@

ammeter

to the drain side of the

side to the main amp. PWB.

R75 lR on the main amp. PWB.

as they were, after adjust-

,

@

their

match-

for the

Fig.

used

when checking

If this happens, measure the collector voltage

LiR as

Q704 L/R.

(2)

protection

The collector

Q707

position

respective

5

o

Adjusting

sure

Be

adjustment is completed.

Insert the shorting

COUPLING/CONDENSER

CONDENSER COUPLING, turn the speaker

switch ON, and

it is at the

circuit may operate when

voltage

L/R. In this case, change the

Gate

the

to

of

measure the

and

electrodes.

(G)

output

perform

gate

the

Q706

voltage at FET

potential

same

L/R

and the

voltage between

DC

this adjustment after

in the input, set

COUPLING

the

adjustment with no load.

701 L/R.

as FET 701

checking the

base

voltage

measurement

the input

the DIRECT

switch to

selector

of

the

Fig. 5

DC

IEI|OZR

FETT02R

o

Adjusting the input DC

Insert the

shorting

COUPLING/CONDENSER

to the input, set

COUPLING

FETTOZL

Fig.6

Fig.

the DIRECT

switch

CONDENSER COUPLING, turn the speaker

selector switch

ON with

performing

no load for more

the adjustment.

ON,

turn

and

than about 8

To adjust Lch, connect the@

to 13

Q

To adjust the Rch, connect the

and

terminal of

side to

14

the

side to 14 terminal.

Q

terminal.

ment using R152L

reading

(within

the

main amp.

or R752R respectively

t

0.5V) with the 3mV range.

side

@

Then

powet

the

minutes

of

the DC

side to l5 terminal,

perform

PWB,

arnmeter

and the

the adjust-

for

(Fig.

6

switch

before

zero

a

7)

Fig.7

Perform adjustment

necting the DC ammeter

speaker A

(within

o

Adjusting

(1)

Adjusting

Adjust sensitivity

completed.

terminals

+5mV),

the

the meter sensitivity

With no load applied

minals, connect the

to

terminal

In this

indicates

Then

indicates lW

(INPUT)

case, adjust

1W.

adjust R955R

using

R753L

to the

Lch or Rch for a

of

the l00mV range.

with

meter

of the meter after zero

audio oscillator

to feed in a signal

the

input

so that

(Fig.

7).

or

R753R after

and

@

(Fig.

to the speaker

of lkHz.

so

that

the

the Rch

sides

zero

7)

of

reading

ter-

Q

adjustment

to the input

pointer

Lch

pointer

also

con-

the

is

-5-

HITACHI

HMA.6500

CHECKING

When

the

output circuit is

power

MOS

FET, etc.,

the the

1. Operation

power

Connect the

with

connect).

lkHz

voltage

Under these

nals of

using a

detection circuit

speaker

circuiting

Next,

10

put

that

2. Operation check

Make

approx. 4 seconds

with

nect).

(Area

ASO

speaker

protection

check

MOS FET

audio

speaker

the

the frequency

Set

and adjust

at the speaker

conditions,

the channel

lead wire, etc.

terminals

is removed.

turn off the

sec., turn the

comes

out

the ASO

sure

that the relay

the

speaker

THE

of

Safe Operation)

OPERATION

repaired

perform

by replacing

an

operation

detection

circuit.

of

the ASO

oscillator

detection circuit

to the INPUT

terminals unloaded (speaker

of the audio

the level

operate, no

even

of the speaker

detection

of

terminals

of the input

terminals

short-circuit

to which the

If this

short-circuit makes

if

lead wire

the

power

switch and,

switch

circuit

the

after

speaker

protection

operates(a

power

the

unloaded

ACvolîmeler 0scilloscope

protection

TVpe

of

l Muting circuil

Protection

2

3

power

l\4OS FET

protection

Speaker

(DC

circuit

detection

circuit)

circuit

circuit)

protection

voltage

protection

/

signal so

is approx. 5V

the

input

output

on again.

terminals,

is operating normally.

click

switch

(speaker:

o

Phenomena and remedy

circuil

the

of

(ASO

OF

the

check

circuit

and

for

the

terminals

:

dis-

oscillator

that

the

rms.

speaker

signal is applied

appears

used

after

circuit

sound is

Phenomenon

protecîion No sound comes

4 rec. after the

switch is turned

I No sound

2. When the

termi-

the

ASO

at the

for short-

approx.

When

out-

this indicates

heard)

is turned

is turned becomes

when the

No

sound comes out.

Neutral

is more

After the

is tumed

tum ON

on

discon-

Fig.

when the

when

circuit

out about

on

comes out

power

ON the relay

ON, then

signal is

point

voltage

i

thil

2V

power

ON, rclay doesn't

on

at

8

the

operates

power

switch

OFF

applied

switch

THE

proîection

Cause

Short circuiî of

speaker output

teminal

DC leakage of control amp

faulty,

PROTECTION

Next,

when a resistor

(1.5V)

cells

printed

audio

the

relay

turns off

are

taken

away,

polarities

the

mentioned

relay.

indicates

normally.

check

Remove the FET.

In the case

touching the black

the

drain of the FET,

after

applying the

test probe

And next,

simultaneously

In

the case of a P

the tester

circuit operates

power

amp.

,

etc

operation

If

this operation

that

Moreover,

so that nearby

of checking

of an N channel

to the source

when brushing

with

are applied

Turn

check whether

teminal is

or

not, and tum ON again.

I ln care

switch has been set to

DIRECT COUPLING:

If the fault is corrected

by setting it to coNDEN-

SER COUPLING, control amp. DC is leaking so

repair the control

2 In case the input s€lect

vitch

CONDENSER COUP.

LINC:

Repair faulty

power

of

approx.

are connected

wiring board

within I

the relay

of the

dry cell

to check

makes

the speaker

test probe

black test

your

channel, the

in reverse.

Remedy

Normal

the

off

short

the

has

amp

protection

pay

attention

parts

are not short-circuited.

POWER

the

of the tester

and the red test

probe

at the same

hand,

power

switch,

the

speaker

circuited

input select

mp

been set to

parts

in

CIRCUIT

l0

kohms

in series

and the

operates

FET, it is normal :

both

the current

red and black test probes

jumper

sec.

When

again.

and

carry

the

the relay

circuit

during

MOS

probe

to

the

time, a current

gate

the

and2

to R902

wire

the

dry cells

Next,

out

the above-

operation

activate,

is operating

this

operation

FET

(ohm

range

the

to

gate

and

and source

stops.

source,

the red

dry

on

the

@

change

of

the

this

When

to

)

flows.

of

î

,

î

^

î

-6-

HITACH]

HMA.6500

^

,^

DESCRIPTION

o

Protection circuit

exclusive

an

(1)

IC

HA12002,

protect

Muting

the speaker and

circuit

This keeps the relay

power

sound during

This

voltage applied to

R908, and

(2)

Protection

tection

switch has

is determined

circuit)

C905.

of

been turned on to reduce shock

ON/OFF

by

speaker

the

FEATURES

HITACHI have

tion

device

POWER MOS

plification

engineering only

1.

Design

wide band

POWER N/OS

The

impedance and

These two merits

simply

a

there

why

has an adverse affect on the

also

why

tion factor. ln

excellent,

is

operation is ensured even in

ciesand notch

The design

across a wide band

output of 50 watts

(2O

Hz-2O kHz)

total

2.

amplifier featuring

DC

power

capacitors

The

NFB

been

great

phase

low

noise transistors

voltage

for

a

more, there DENSER

developed

for

audio applications.

FET are top-class, thls

stage. This is a

the

oriented

for the

designed circuit configuration.

is minimai noise

there

the switching

makes

harmonic

transmission

and even

loop

put

aside in this

improvement in the low-frequency-range

characteristics.

and well-matched

reduction in center

is a DIRECT

COUPLTNG switch

OF

power

off

operation

@

toward low

is

addition, the

distortion is dramatically

THE

protection

amplifier.

for

approx.

rise

the

best

it

provide

no

time

IC90l

of

(DC

voltage

a complementary

design which

in sound

in

sound

FET features

is

voltage-driven

a

a high

deterioration

for

a low

NEW

circuit,

4 sec

power

of the

constant

and is set by R907,

detection/pro-

Since

model features

quality.

distoftion

quality

a high

power

phase

or

frequencv

speed is fast,

drift

quality,

sound

in the

the high frequen-

distortion

with a continuous

per

channel,

with no

distortion.

accurate waveform

have

been

min.,

more than

eliminated

the input capacitors

DC amplifier to

first

The

with a high

stage

withstanding

pairing

characteristics

point

drlft. Further-

COUPLING/CON

which

CIRCUIT

When a DC voltage appears

used

is

after

switch.

to

the

of the

MOS FET which

both the N-channel and P-channel

a simple 3-stage circuit conf iguration

makes for

across

device.

gain

response

reduéed.

at 8

from

effect a

employs

is

a low distortion across a

input

and

This

is

which

and

distor-

stable

factor

power

ohms

0.A2%

the

have

pro-

output, a

to

sensitivity

(3)

Protection

circuit) When overcurrent flows to thé

Vcs between the

increases,

applied to

displays superb characteristics

vided

caused

externally control

3. Connection This amplif ier can

speakers,

ers

switch,

produced

You

can also listen

speaker other

4. High-reliability ln

order

current limiter

tion of

voltage

This clrcuitry features high

enables

5.

Large-sized

The model

which enable the

right

channels

checked.

you

would expect

FET amplif

rithmic

plays

they

displayed

at

the neutral

relay turns off when approx. l

IC90l via R901,

of

@

adjustment

of

Q70ó

pin@of

complementary

wide band and

to safeguard the

by DC component

connected equipment

amplifier).

facilities

and

by selecting them

you

by each system.

system in

speaker systern

protect

to

the

area

detection

resistor.

Power

MOS

gzte

and source of FET7OI

and

Q707

tC901 and the relay

as a

characteristics

including

which is

speakers

for two

accommodate

can

pairs

compare

to the

one room

in another

protection

circuit

circuitry

the POWER

which relles

of

safe operation

circuit have

FET

turn

power

Ìeakage

sound from

reliability

to cope

it

power

comes

and also the

Their size and

ier

compression circuit for

of the

detected

can track

values to

with

meters

with

balance

The

peak

be

accidents.

(peak

large-sized

between the left

performance

to find

power

peak

signals

read

meters

out directlV

in a POWER

values

output level

and enable

point

is applied

3V

R902 R903 is the

(ASO

protection

output, the voltage

ON, the

poweram-

the

devoted

from

(such

speakers

of

two

with

the

and from

room.

MOS

on the

been

rneters)

power

adopt

RMS value

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voltage

is

turned off.

amplif ica-

of this

to

damage

from

the

as

the

pairs

the speak-

sound

re-

one

the

FET,

detec-

and

DC

installed.

which

meters

and

to

be

are

what

MOS

a loga-

dis-

why

the

of

a

of the

is

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-7

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