Pioneer A-50, A-70 Service manual

INTEGRATED AMPLIFIER

A-70-K

A-70-S
A-50-K
A-50-S
A-50

ORDER NO.

RRV4385

A-70-K

THIS MANUAL IS APPLICABLE TO THE FOLLOWING MODEL(S) AND TYPE(S).

Model Type Power Requirement Remarks

A-70-K/-S SYXE8 AC 220 V to 230 V

A-50-K/-S SYXE8 AC 220 V to 230 V

A-50 FXE AC 110 V

PIONEER CORPORATION 1-1, Shin-ogura, Saiwai-ku, Kawasaki-shi, Kanagawa 212-0031, Japan

PIONEER ELECTRONICS (USA) INC. P.O. Box 1760, Long Beach, CA 90801-1760, U.S.A.
PIONEER EUROPE NV Haven 1087, Keetberglaan 1, 9120 Melsele, Belgium
PIONEER ELECTRONICS ASIACENTRE PTE. LTD. 253 Alexandra Road, #04-01, Singapore 159936

PIONEER CORPORATION

2012

K-FZV NOV.

2012 Printed in Japan

1

2 3 4

SAFETY INFORMATION

A

This service manual is intended for qualified service technicians ; it is not meant for the casual do-it-
yourselfer. Qualified technicians have the necessary test equipment and tools, and have been trained
to properly and safely repair complex products such as those covered by this manual.
Improperly performed repairs can adversely affect the safety and reliability of the product and may
void the warranty. If you are not qualified to perform the repair of this product properly and safely, you
should not risk trying to do so and refer the repair to a qualified service technician.

WARNING
This product contains lead in solder and certain electrical parts contain chemicals which are known to the state of California to
cause cancer, birth defects or other reproductive harm.

B

56 noitisoporP - 6.94252 noitceS edoC ytefaS & htlaeH

C

D

E

F

2

1

2 3 4

A-70-K

5

6 7 8

CONTENTS

SAFETY INFORMATION.......................................................................................................................................................... 2

1. SERVICE PRECAUTIONS.................................................................................................................................................... 4

1.1 NOTES ON SOLDERING ...............................................................................................................................................4

2. SPECIFICATIONS................................................................................................................................................................. 5

2.1 ACCESSORIES.............................................................................................................................................................. 5

2.2 SPECIFICATIONS ..........................................................................................................................................................5

3. BASIC ITEMS FOR SERVICE ..............................................................................................................................................6

3.1 CHECK POINTS AFTER SERVICING ........................................................................................................................... 6

3.2 PCB LOCATIONS...........................................................................................................................................................7

3.3 JIGS LIST ....................................................................................................................................................................... 8

4. BLOCK DIAGRAM .............................................................................................................................................................. 10

4.1 OVERALL CONNECTION DIAGRAM (A-70-K/-S) ....................................................................................................... 10

4.2 OVERALL CONNECTION DIAGRAM (A-50-K/-S, A-50).............................................................................................. 12

4.3 BLOCK DIAGRAM........................................................................................................................................................ 14

5. DIAGNOSIS ........................................................................................................................................................................ 16

5.1 TROUBLESHOOTING..................................................................................................................................................16

5.2 PROTECTION CIRCUIT DESCRIPTION .....................................................................................................................21

5.3 IC INFORMATION ........................................................................................................................................................23

6. SERVICE MODE................................................................................................................................................................. 26

7. DISASSEMBLY ................................................................................................................................................................... 27

8. EACH SETTING AND ADJUSTMENT ................................................................................................................................ 49

8.1 HOW TO CHECK THE FIRMWARE VERSION ............................................................................................................ 49

8.2 FIRMWARE UPDATING ...............................................................................................................................................49

9. EXPLODED VIEWS AND PARTS LIST............................................................................................................................... 52

9.1 PACKING SECTION .....................................................................................................................................................52

9.2 EXTERIOR SECTION (A-70) ....................................................................................................................................... 54

9.3 EXTERIOR SECTION (A-50) ....................................................................................................................................... 58

9.4 FRONT SECTION ........................................................................................................................................................60

10. SCHEMATIC DIAGRAM .................................................................................................................................................... 62

10.1 INPUT ASSY (1/2)...................................................................................................................................................... 62

10.2 INPUT ASSY (2/2)...................................................................................................................................................... 64

10.3 USB ASSY (1/2) ......................................................................................................................................................... 66

10.4 USB ASSY (2/2) ......................................................................................................................................................... 68

10.5 PHONO ASSY............................................................................................................................................................70

10.6 FRONT, FUNCTION LED, VOLUME, FUNCTION SW, SECOND POWER and HEADPHONE ASSYS.................... 72

10.7 D-AMP ASSY (1/3) ..................................................................................................................................................... 74

10.8 D-AMP ASSY (2/3) ..................................................................................................................................................... 76

10.9 D-AMP ASSY (3/3) ..................................................................................................................................................... 78

10.10 D-AMP SUB ASSY ...................................................................................................................................................80

10.11 SUB INPUT, POWER, CONNECTOR and AC LINE (A-70-K/-S) ASSYS ................................................................ 82

10.12 PCB GUIDE-1 - PCB GUIDE-3 (A-70-K/-S) and PCB GUIDE-4 - PCB GUIDE-10 .................................................. 84

11. PCB CONNECTION DIAGRAM........................................................................................................................................ 86

11.1 INPUT ASSY .............................................................................................................................................................. 86

11.2 USB ASSY.................................................................................................................................................................. 90

11.3 PHONO ASSY............................................................................................................................................................92

11.4 FRONT ASSY............................................................................................................................................................. 94

11.5 FUNCTION LED, VOLUME, FUNCTION SW, SECOND POWER and HEADPHONE ASSYS..................................96

11.6 D-AMP ASSY and D-AMP SUB ASSY.......................................................................................................................98

11.7 SUB INPUT ASSY, POWER ASSY and CONNECTOR ASSY.................................................................................100

11.8 AC LINE ASSY, PCB GUIDE-1 - PCB GUIDE-3 (A-70-K/-S) and PCB GUIDE-4 - PCB GUIDE-9 .......................... 102

12. PCB PARTS LIST ...............................................................................................................

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

........... 104

A

B

C

D

E

F

A-70-K

5

6 7 8

3

1

2 3 4

1. SERVICE PRECAUTIONS

1.1 NOTES ON SOLDERING

• For environmental protection, lead-free solder is used on the printed circuit boards mounted in this unit.

A

Be sure to use lead-free solder and a soldering iron that can meet specifications for use with lead-free solders for repairs
accompanied by reworking of soldering.

• Compared with conventional eutectic solders, lead-free solders have higher melting points, by approximately 40 ºC.
Therefore, for lead-free soldering, the tip temperature of a soldering iron must be set to around 373 ºC in general, although
the temperature depends on the heat capacity of the PC board on which reworking is required and the weight of the tip of
the soldering iron.

Do NOT use a soldering iron whose tip temperature cannot be controlled.

Compared with eutectic solders, lead-free solders have higher bond strengths but slower wetting times and higher melting
temperatures (hard to melt/easy to harden).

B

The following lead-free solders are available as service parts:

• Parts numbers of lead-free solder:
GYP1006 1.0 in dia.
GYP1007 0.6 in dia.
GYP1008 0.3 in dia.

C

D

E

F

4

1

2 3 4

A-70-K

5

2. SPECIFICATIONS

2.1 ACCESSORIES

6 7 8

Remote control unit (A-70-K/-S : CARTA70)
(A-50-K/-S, A-50 : CARTA50)

AC Power cord (A-70-K/-S, A-50-K/-S : CJA2B135ZV)
(A-50 : CJA2L133ZV)

Operating instructions (A-70-K/-S, A-50-K/-S : CQX1A1693Z)
(A-50 : CQX1A1696Z)

Short pin plug x 2 (CJT1A100)

2.2 SPECIFICATIONS

Amplifier section

Power output specification is for when power supply is 230 V.

(A-70-K/-S, A-50-K/-S)

Power output specification is for when power supply is 110 V.

(A-50)

•Continuous power output (both
channels driven at 20 Hz to 20 kHz)

A-70/A-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 W + 90 W

(THD 0.5 %, 4 Ω)

A-70/A-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65 W + 65 W

(THD 0.5 %, 8 Ω)

Audio section

•Input (Sensitivity/Impedance)

SACD/CD, NETWORK, TUNER, RECORDER, AUX (A-50

only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 mV/50 kΩ

POWER AMP DIRECT . . . . . . . . . . . . . . . . . . . . . . 1 V/10 k Ω

PHONO (MM). . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 mV/50 k Ω

PHONO (MC) . . . . . . . . . . . . . . . . 0.24 mV/100 Ω(A-70 only)

COAXIAL . . . . . . . . . . . . . . . . . . 500 mVp-p/75 Ω (A-70 only)

•Output (Level/Impedance)

RECORDER OUT . . . . . . . . . . . . . . . . . . . . . . 200 mV/2.2 kΩ

•Frequency response

SACD/CD, NETWORK, TUNER, RECORDER, AUX (A-50

only). . . . . . . . . . . . . . . . . . . . . . . . . . 5 Hz to 20 kHz ±2 dB*

PHONO (MM). . . . . . . . . . . . . . . . 20 Hz to 20 kHz ±0.5 dB*

PHONO (MC) . . . . . . . . 20 Hz to 20 kHz ±0.5 dB*(A-70 only)

* Measured with DIRECT button switched on.

AAA/R03 dry cell battery x 2

Caution Sheet (A-70-K/-S: CQE1A569Z)

Warranty card (CQE1A541Z)

Miscellaneous

Power requirements

A-70-K/-S, A-50-K/-S

A-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AC 110 V, 60 Hz

Power consumption

A-70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 W

A-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72 W

In standby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 W

Dimensions

A-70 . . . . . . . .435 mm (W) x 141.5 mm (H) x 361.5 mm (D)

A-50 . . . . . . . . . 435 mm (W) x 138.5 mm (H) x 357 mm (D)

Weight (without package)

A-70-K/-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.1 kg

A-50-K/-S . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 kg

A-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.0 kg

Note

• Specifications and the design are subject to
possible modifications without notice, due to
improvements.

• Corporation and product names mentioned herein
are trademarks or registered trademarks of the
respective corporations.

. . . . . . . . . . AC 220 V to 230 V, 50 Hz

A

B

C

D

•Tone control

-

(When VOLUME is set to

Bass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .± 10 dB (100 Hz)

Treble. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .± 10 dB (10 kHz)

30 dB)

•Signal-to-Noise Ratio (IHF SHORTED,
A-NETWORK)

SACD/CD, NETWORK, TUNER, RECORDER, AUX (A-50

only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 dB*

PHONO (MM, 5 mV input). . . . . . . . . . . . . . . . . . . . . 89 dB*

PHONO (MC, 0.5 mV input). . . . . . . . . . . 74 dB* (A-70 only)

* Measured with DIRECT button switched on.

•Speaker load impedance

A, B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Ω to 16 Ω

A+B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Ω to 32 Ω

Bi-wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Ω to 16 Ω

5

6 7 8

A-70-K

E

F

5

1

2 3 4

3. BASIC ITEMS FOR SERVICE

3.1 CHECK POINTS AFTER SERVICING

A

To keep the product quality after servicing, confirm recommended check points shown below.

No. Procedures Check points

Check the symptom pointed out by a customer The pointed content should not reoccur

1

Check each input and main VOL (check the

2

operation of selector)

Check the tone control, balance, and function The sound quality or right and left balances should change

3

B

Check LOUDNESS and DIRECT functions The sound quality should change by setting LOUDNESS

4

Check POWER AMP DIRECT terminal

5

(connected from pre-out terminal of AV AMP to
POWER AMP DIRECT terminal)

6 Check SPEAKER A/B and headphone terminal There should not be defect in sound such as noise

Check the external package Check scratch or taint is not generated after accepting the

7

Sound and operation should not be defective

The sound is output by selecting an analog-connected input
with a selector and the sound volume should change by
rotating main VOL knob

by rotating each VOL knob

function to ON. LOUDNESS function should be disabled by
setting DIRECT function to ON.

The sound volume should change by adjusting the sound
volume of connected AV AMP. The sound volume should not
be changed by the main VOL on the main unit.

repair

C

See the table below for the items to be checked regarding audio.

Item to be checked regarding audio

Distortion

Noise

Volume too low

Volume too high

Volume fluctuating

Sound interrupted

D

E

F

6

1

2 3 4

A-70-K

5

3.2 PCB LOCATIONS

FUNCTION LED ASSY

E

G

FUNCTION

SW ASSY

6 7 8

VOLUME ASSY

F

FRONT ASSY

D

HEADPHONE ASSY

I

SECOND POWER ASSY

H

X

PCB GUIDE -9

A

INPUT ASSY

A

C

PHONO ASSY

B

USB ASSY

N

CONNECTOR

ASSY

L

SUB INPUT

ASSY

PCB GUIDE -2

(A-70-K/SYXE8,

A-70-S/SYXE8 only)

Q

PCB GUIDE -1

(A-70-K/SYXE8,

A-70-S/SYXE8 only)

P

J

D-AMP ASSY

O

AC LINE ASSY

(A-70-K/SYXE8,
A-70-S/SYXE8 only)

K

D-AMP SUB ASSY

M

POWER ASSY

PCB GUIDE -3

(A-70-K/SYXE8,
A-70-S/SYXE8 only)

R

B

C

D

PCB GUIDE -7

V

T

PCB GUIDE -5

U

PCB GUIDE -6

S

PCB GUIDE -4

A-70-K

5

6 7 8

W

PCB GUIDE -8

PCB GUIDE -10

Y

E

F

7

1

2 3 4

NOTES: - Parts marked by “NSP” are generally unavailable because they are not in our Master Spare Parts List.

-

Therefore, when replacing, be sure to use parts of identical designation.

A

Mark No. Description Part No.

The > mark found on some component parts indicates the importance of the safety factor of the part.

Mark No. Description Part No.

LIST OF ASSEMBLIES

NSP

1..MAIN ASSY (A-70-K/-S) COP12479C

2..INPUT ASSY AZW7669

2..USB ASSY AZW7673

2..PHONO ASSY AZW7671

2..AC LINE ASSY AZW7677

2..PCB GUIDE-1 COP12479C-5

2..PCB GUIDE-2 COP12479C-7

2..PCB GUIDE-3 COP12479C-8

B

C

D

2..PCB GUIDE-10 COP12479C-9

NSP

1..MAIN ASSY (A-50-K/-S) COP12479F

2..INPUT ASSY AZW7670

2..USB ASSY AZW7675

2..PHONO ASSY AZW7672

2..PCB GUIDE-10 COP12479F-9

NSP

1..MAIN ASSY (A-50) COP12479G

2..INPUT ASSY AZW7706

2..USB ASSY AZW7676

2..PHONO ASSY AZW7708

2..PCB GUIDE-10 COP12479G-9

NSP

1..FRONT ASSY (A-70-K/-S

2..FRONT ASSY AZW7678

2..FUNCTION LED ASSY AZW7680

2..VOLUME ASSY AZW7682

2..FUNCTION SW ASSY AZW7683

2..SECOND POWER ASSY AZW7685

2..HEADPHONE ASSY AZW7686

2..PCB GUIDE-8 COP12478B-9

2..PCB GUIDE-9 COP12478B-10

NSP

1..FRONT ASSY (A-50-K/-S, A-50) COP12478C

2..FRONT ASSY AZW7679

2..FUNCTION LED ASSY AZW7681

2..VOLUME ASSY AZW7682

2..FUNCTION SW ASSY AZW7684

2..SECOND POWER ASSY AZW7685

2..HEADPHONE ASSY AZW7686

2..PCB GUIDE-8 COP12478C-9

2..PCB GUIDE-9 CO

) COP12478B

P12478C-10

1..D-AMP ASSY (A-70-K/-S) COP12476B

NSP

2..D-AMP ASSY AZW7694

1..D-AMP ASSY (A-50-K/-S, A-50) COP12476C

NSP

2..D-AMP ASSY AZW7695

1..D-AMP SUB ASSY COP12477B

NSP

2..D-AMP SUB ASSY AZW7696

1..POWER ASSY (A-70-K/-S) COP12480C

NSP

2..POWER ASSY AZW7687

2..SUB INPUT ASSY AZW7691

2..CONNECTOR ASSY AZW7693

2..PCB GUIDE-4 COP12480C-4

2..PCB GUIDE-5 COP12480C-5

2..PCB GUIDE-6 COP12480C-6

2..PCB GUIDE-7 COP12480C-7

1..POWER ASSY (A-50-K/-S) COP12480F

NSP

2..POWER ASSY AZW7689

2..SUB INPUT ASSY AZW7692

2..CONNECTOR ASSY AZW7693

2..PCB GUIDE-4 COP12480F-4

2..PCB GUIDE-5 COP12480F-5

2..PCB GUIDE-6 COP12480F-6

2..PCB GUIDE-7 COP12480F-7

1..POWER ASSY (A-50) COP12480G

NSP

2..POWER ASSY AZW7704

2..SUB INPUT ASSY AZW7710

2..CONNECTOR ASSY AZW7693

2..PCB GUIDE-4 COP12480G-4

2..PCB GUIDE-5 COP12480G-5

2..PCB GUIDE-6 COP12480G-6

2..PCB GUIDE-7 COP12480G-7

3.3 JIGS LIST

E

25P + 19P extension jig cable GGD1830 Diagnosis

UPDATE JIG GGF1675 Farmware Update

F

8

1

Name Jig No. Remarks

A-70-K

2 3 4

5

6 7 8

A

B

C

D

E

F

A-70-K

5

6 7 8

9

1

N

Y

3

2

2 3 4

4. BLOCK DIAGRAM

4.1 OVERALL CONNECTION DIAGRAM (A-70-K/-S)

A

J

J 1/3 - J 3/3

POWER ASSY

M

(AZW7687)

B

D-AMP ASSY
(AZW7694)

B 1/

B

USB ASS
(AZW767

D-AMP SUB ASSY

K

(AZW7696)

C

Main Trans

D

AC

O

E

FRONT ASSY

D

SECOND POWER ASSY

H

(AZW7678)

(AZW7685)

FU

G

(AZ

HEADPHONE ASSY

I

(AZW7686)

VOLUME ASSY

F

F

(AZW7682)

10

A-70-K

1

2 3 4

B 1/2 - B 2/2

B

USB ASSY
(AZW7673)

5

6 7 8

SUB INPUT ASSY

L

A

(AZW7691)

PHONO ASSY

CONNECTOR ASSY

N

C

(AZW7671)

B

(AZW7693)

A 1/2 - A 2/2

A

AC LINE ASSY (AZW7677)

O

FUNCTION LED ASSY

E

(AZW7680)

INPUT ASSY
(AZW7669)

Pre
Trans

PCB GUIDE-1

P

(COP12479C-5)

PCB GUIDE-2

Q

(COP12479C-7)

PCB GUIDE-3

R

(COP12479C-8)

PCB GUIDE-4

S

(COP12480C-4)

PCB GUIDE-5

T

(COP12480C-5)

PCB GUIDE-6

U

(COP12480C-6)

PCB GUIDE-7

V

(COP12480C-7)

C

D

E

G

ASSY

2)

FUNCTION SW ASSY
(AZW7683)

When ordering service parts, be sure to refer to "EXPLODED VIEWS and PARTS LIST" or "PCB PARTS LIST".
The > mark found on some component parts indicates the importance of the safety factor of the part.
Therefore, when replacing, be sure to use parts of identical designation.

5

PCB GUIDE-8

W

(COP12478B-9)

PCB GUIDE-9

X

(COP12478B-10)

PCB GUIDE-10

Y

(COP12479C-9)

A-70-K

6 7 8

F

11

1

Y

S

2

U

A

2 3 4

4.2 OVERALL CONNECTION DIAGRAM (A-50-K/-S, A-50)

A

J

POWER ASSY

M

(A-50-K/-S : AZW7689)

B

(A-50 : AZW7704)

D-AMP ASSY
(AZW7695)

D-AMP SUB ASSY

K

(AZW7696)

J 1/3 - J 3/3

B 1/

B

USB ASS
(A-50-K/­(A-50

C

D

E

FRONT ASSY

D

SECOND POWER ASSY

H

(AZW7679)

(AZW7685)

F

G

(

HEADPHONE ASSY

F

(AZW7686)

VOLUME ASSY

F

I

(AZW7682)

12

1

2 3 4

A-70-K

5

B 1/2 - B 2/2

B

USB ASSY
(A-50-K/-S : AZW7675)
(A-50 : AZW7676)

6 7 8

L

SUB INPUT ASSY
(A-50-K/-S : AZW7692)
(A-50 : AZW7710)

C

CONNECTOR ASSY

N

(AZW7693)

PHONO ASSY
(A-50-K/-S : AZW7672)
(A-50 : AZW7708)

A

B

FUNCTION LED ASSY

E

(AZW7681)

A 1/2 - A 2/2

A

INPUT ASSY
(A-50-K/-S : AZW7670)
(A-50 : AZW7706)

PCB GUIDE-4

S

(A-50-K/-S : COP12480F-4)
(A-50 : COP12480G-4)

PCB GUIDE-5

T

(A-50-K/-S : COP12480F-5)
(A-50 : COP12480G-5)

PCB GUIDE-6

U

(A-50-K/-S : COP12480F-6)
(A-50 : COP12480G-6)

PCB GUIDE-7

V

(A-50-K/-S : COP12480F-7)
(A-50 : COP12480G-7)

PCB GUIDE-8

W

(COP12478C-9)

C

D

E

G

ASSY

2)

FUNCTION SW ASSY
(AZW7684)

5

PCB GUIDE-9

X

(COP12478C-10)

PCB GUIDE-10

Y

(A-50-K/-S : COP12479F-9)
(A-50 : COP12479G-9)

A-70-K

6 7 8

F

13

1

u

CM6631

192kHz/32bit

FLASH

DAC

192kHz/32bit

ES9011

LPF

USB

Input

Power Amp

µCOM

INPUT

SELECTOR

(NJM1112)

E.Volume

(NJM1194)

PWM

-6V
Reg

+6V
Reg

+5V
Reg

+3.3V

Reg

+3.3V

Reg

+1.2V

Reg

+3.3V

Reg

FRONT

-15V
Reg

+15V

Reg

-8V
Reg

+8V
Reg

APD

(NJU7181)

P-AMP

DIRECT

(RL34)

a

n

TONE

&

LOUDNESS

-5V
Reg

+5V
Reg

POWER

MM/
MC

SMALL

SIGNAL

RELAY

4.3 BLOCK DIAGRAM

A

2 3 4

B

C

D

E

POWER

Sub Trans secandary DC

IC91 IC92

+3.3V

Reg

USB

+8V Tone Balance SW Input Selecter

+5V
Reg

A-70 only

FRONT

Power SW STB LED IR Bl

FLASH

CM6631

192kHz/32bit

MM/

MC

for RECOUT&APD

SELECTOR

(NJM1112)

INPUT

192kHz/32bit

for AMPOUT

APD

(NJU7181)

DAC

ES9011

A-70 only

COAXIAL

SACD/CD

TUNER

NETWORK

AUX(A-50 only)

PHONO

RECODER

P-AMP

DIRECT

RECODER
OUT

SR I/O -18V -15V

Input

µCOM

LPF

TONE

LOUDNESS

E.Volume

(NJM1194)

+18V

IC93 IC98 IC101 IC95

+15V

Reg

-15V
Reg

IC94 IC99 IC102 IC96

Vol

+6V

IC69 IC70

+3.3V

Reg

+3.3V

IC71

+1.2V

Reg

+15V

+8V
Reg

-8V
Reg

14dB

+6V

+7.5V

-7.5V

+3.3V

Reg

+5V
Reg

-5V
Reg

P-AMP

DIRECT

(RL34)

+15V

-15V

3dB

+6V
Reg

-6V
Reg

A-70 only

SMALL

SIGNAL

RELAY

Differenti
Bufffer

signal : inversio

GND : inversio

0dB

F

14

1

2 3 4

A-70-K

5

POWER AMP GAIN 23dB

5

6

Power Amp

Daughter board

Gate

Driver

12V Reg

LPF

-12V
Reg

+12V

Reg

PWM

RELAY

-15V
Reg

+15V

Reg

V-6V

SMALL

SIGNAL

RELAY

RELAY

6 7 8

A

3dB

V

g

g

0 only

Input Selecter

SMALL

SIGNAL

RELAY

Differential
Bufffer

0dB

signal : inversion

GND : inversion

Blue LED

0dB

HP

POWER AMP GAIN 23dB

PWM

+35V

-35V

Power Amp

Daughter board

Gate

Driver

12V Reg

+35V

-35V

LPF

+20V

-20V -15V

+15V

IC4908 IC7251

+15V

Reg

-15V
Reg

IC4909 IC7252

+12V

Reg

-12V
Reg

RELAY

RELAY

B

C

D

E

5

A-70-K

6 7 8

F

15

1

5. DIAGNOSIS

5.1 TROUBLESHOOTING

A

1) No sound

2 3 4

[Status of product]

 Insert AC Power cord

 Main unit POWER SW: ON

No sound

Is the power supply

turned ON ?

B

No sound (all input)

C

 POWER ON operation by remote control unit
 Select SPEAKER-A

 INPUT : USB (SACD/CD in case of A-50)

Is the standby LED

blinking ?

Protection circuit is operating

(For the type, refer to the 5.2 PROTECTION
CIRCUIT DESCRIPTION)

Is the voltage of

V+3.3V_STB (BN94: 3 pin)

at 3.3V ?

Is BN94: 1 pin

(AC DET) set to "L" ?

Is the voltage of

IC11: 11,22,28,50,75,100

pins at 3.3V ?

Is there

square waveform of

8MHz on IC11:

12 pin?

Is the voltage of

IC91: 2 pin approx.



IC91 failure



Q903, D917 failure



Connection failure between CN4100 and BN94



Connection failure between CN4000 and CN17



Connection failure between BN12 and CN12



X101,R108,R109,C102,C103

: solder failure

5V ?

YES

NO

Is there AC waveform on

D913 anode side ?



D913 failure



D914 failure



F901 failure



T901 failure



JK90 connection failure

D

relay "click" and is it turned

ON after the power supply

E

F

Does the protection

is turned ON ?

A

Is IC11: 70 pin

(SPEAKER A) set to "H" ?

Is the voltage between

both terminals of the

C4071, C4171 at 8.5V ?

RY4000,RY4100: failure



Is IC11: 82 pin(P_DOWN)

set to "L" ?



IC11 failure

Is the SPEAKER A LED

lighting ?



S805 failure



IC11 failure

Is the voltage of

V-12RY2 approx. -12V ?



Q7201-Q7206: failure



R7589,R7590,R7592,R7598

: disconnection



Connection failure between CN4100 and BN94



Connection failure between CN4000 and CN17



Connection failure between BN12 and CN12



R189,R163,Q101,C125 :



IC11 failure

IC7252 failure




R7457 disconnection

solder failure or failure

16

A-70-K

1

2 3 4

5

A

6 7 8

YES

NO

Is there residual
waveform of the switching
on SP OUT terminal?

Is there output at
REC OUT terminal after
selecting the input line ?

Is there output at input
signal to the POWER
AMP DIRECT ?

(sine waveform of approx. 420 kHz
and approx. 1.5 Vrms)



Refer to the 7) D-AMP SUB ASSY diagnosis flowchart.

Whether change the
DC voltage of R219 when
operating the input
selector ?



IC11 solder failure or failure



IC31 communication failure or solder failure or failure

Is there a signal
at IC34 : 25 pin
(VOL IC) ?

Whether change the
DC voltage of R251 when
operating the volume ?



VR86 solder failure or failure



BN87,CN87 : solder failure or failure



25p FFC connection failure



CN83,BN96 : solder failure or failure



VR85 solder failure or failure



BN85,CN85 : solder failure or failure



19p FFC connection failure



CN81,BN81: solder failure or failure



IC45 solder failure or failure or
check of the power supply



IC11 solder failure or failure



IC34 communication failure or

solder failure or failure

A

B

C

Is there a signal at
CN4200 : 13 pin ?



Connection failure between

CN16 and CN4200

Is there a signal at
C4116 : plus side

Is there a signal at
CN4006 : 8 pin



Check of the connection between CN4007 and CN5002



Check of the connection between CN4107 and CN5102



Check of the connection between CN4006 and CN5001



Check of the connection between CN4106 and CN5101

Is there a signal at
IC40 : 3,5 pins ?

Is there a signal at
IC40 : 1,7 pins ?

Is there a signal
at IC38 : 1 pin,
IC39 : 1 pin ?



IC4202 failure or check of the

power supply



Is XAMUTE set to “H” ?



IC4100 failure or check of the

power supply



Check of the Relay(RL34) for Pure Direct



Check of the Relay ON/OFF signal



Check of the parts of the Relay



IC40 failure or check of the power supply



IC38,IC39 failure or check of the

power supply



Is FUNC_MUTE set to “H” ?

D

E

F

A-70-K

5

6 7 8

17

1

2) No sound (specific input)

2 3 4

A

No sound (specific input)

Is there input signal have
been pointed out at
following pins of the IC31 ?

SACD/CD 3,4 pins
NETWORK 5,6 pins
TUNER 7,8 pins
AUX 11,12 pins

B

IC31 communication failure or solder failure or failure

RECORDER 13,14 pins

3) No sound (PHONO input)

C

D

No sound (PHONO input)

Is there output
both MM and MC ?

[Status of product]

 Insert AC Power cord

 Main unit POWER SW: ON

 POWER ON operation by remote control unit
 Select SPEAKER-A

 INPUT : NETWORK

Input Jack solder failure
Electrolytic capacitor for coupling of each input

: solder failure or failure

[Status of product]

 Insert AC Power cord

 Main unit POWER SW: ON

 POWER ON operation by remote control unit
 Select SPEAKER-A

 INPUT : PHONO(MM or MC)

Whether H/L
operate the voltage
of BN14 : 1 pin
(MM/MC_RLY) ?

RL31,RL32 : solder failure
or failure

Whether H/L
operate the voltage
of R151
(MM/MC_RLY) ?

Connection failure between
BN12 and CN12

Connection failure between
BN14 and CN14

YES

NO

Whether H/L
operate the voltage
of R254
(MM/MC_SW) ?

IC11,R227
: solder failure or failure

A-70 only

SW82 failure
Connection failure between

BN85 and CN85

BN85, CN85 : solder failure
19p FFC connection failure

Is there a signal
at R389,R390 ?

Is there a signal
at IC33 : 1,7 pins ?

E

Is there a signa
at IC31 : 1,2 pins ?

IC31 communication failure or solder failure or failure

F

18

1

Input Jack solder failure

IC33,Q351-Q354 : solder failure or

failure or check of the power supply (±7.5V)
R411-R414 : solder failure

l

Connection failure between CN14 and BN14

A-70-K

2 3 4

5

6 7 8

4) No sound (USB input, COAXIAL/OPTICAL input : A-70 only)

No sound (USB input)

Is the COAXIAL

ally ?

input norm

a data

Is there
at IC72 : 5,6 pins ?

Is there problem in the IC72 ?



X751 12MHz oscillation



Check of the D+3.3_USBSW



Is there a data at 89,93,94 pins



IC63 solder failure or failure

or check of the power supply

No sound (COAXIAL/OPTICAL input)

Is there problem in the IC61(DAC IC) ?



X601 80MHz oscillation



Check of the power supply



Check of the 16,17pins

(communication pin)



Check of the 7 pin(RESET pin)



Is there a data at 44,45,46 pins



Check the connection and setting to the PC

SBDPON

Is U
set to

“H” ?

age of

Is the volt
D+3.3_USB at 3.3V ?

YES

NO

Is there a signal
at IC61:1,2 pins
(DAC IC) ?

a Lch signal at

Is there
IC64 : 1 pin, IC65 : 1 pin ?
Is there a Rch signal at
IC66 : 1 pin, IC67 : 7 pin ?



Check the signal line between

IC64 : 1 pin, IC65 : 1pin and IC34 : 31 pin



Check the signal line between

IC66 : 1 pin, IC67 : 1pin and IC34 : 2 pin



Connection failure between BN11 and CN11



Resistance on the USBDPON line : solder

failure or failure

Connection failure between BN12 and CN12

age of

Is the volt
IC76 : 1 pin at 5V ?




Connection failure between CN4000 and CN17



Connection failure between BN94 and CN4100



IC92 failure



IC61 failure



IC64-IC67 : failure or

check of the power supply

A

B

C

5) No sound (HEADPHONE)

No sound (HEADPHONE)

Is R1242(HP_DET)

“L

” ?

set to

R1242,R1257 :
solder failure or failure

Is R200(RELEY_HP)
set to

“H

” ?

Is there signal at
BN96 : 23,25 pins ?

IC11 solder failure or failure

RL35 solder failure or failure
Check of the power supply

(C561 is between plus and minus : aprrox. 10V)



IC32 failure

Is R1257(HP_DET)
set to

“L

” ?



IC76 failure



XDOFF control failure

[Status of product]

 Insert AC Power cord

 Main unit POWER SW: ON

 POWER ON operation by remote control unit
 Select SPEAKER-A

 INPUT : No specify otherwise

Is BN88 :1pin
(HP_DET) set to “

Q813,R880 :
solder failure or failure

H

” ?

JK81 failure


Connection failure between

BN88, CN88 : solder failure

IC11,R227 :

solder failure or failure

D

BN88 and CN88

E

25p FFC connection failure
BN96,CN83 : solder failure


Connection failure between

JK81 solder failure or failure

5

BN88 and CN88

A-70-K

6 7 8

F

19

1

2 3 4

6) Remote control unit can not be operated

A

Remote control unit can not be operated

Is there batteries in the
remote control unit ?
Is the old batteries in the
remote control unit ?

Is SR cable
connected to the
JK33(SR IN) ?

B

Is there a signal
at CN89 2 pin ?

Is there a signal
at CN89 : 1 pin ?

C

Insert new batteries in the remote
control unit

Disconnect the SR calbe

Is there a signal
at R887 ?

BN89,CN89
: solder failure or failure

JK33,Q303,Q304 : solder failure or failure

[Status of product]

 Insert AC Power cord

 Main unit POWER SW: ON

 Select SPEAKER-A

 INPUT : No specify otherwise

Is there a signal
at R815 ?

Q811,R812
: solder failure or failure

YES

NO

RC81 solder failure or failure

25p FFC connection failure
BN96,CN83,BN89,CN89

: solder failure or failure

R131,R237
: solder failure or failure

IC11 solder failure or failure

D

Is there a signal
at R237(SR_IN) ?

Is there a signal
at R131(SR_IN) ?

7) D-AMP SUB ASSY diagnosis flowchart

Is the voltage of CN5002 : 5 pin,
CN5102 : 6 pin approx. 40V and
CN5002 : 2 pin, CN5102 : 9 pin
approx. -40V
when not connected to the
speaker (No-load)

Is the voltage between

E

plus and minus of the
C4196, C4296 at 12V ?

Is the voltage of C4199
side of the R4182 and
C4299 side of the
R4282 at 9V or more ?

(Note)
Because it operate on the basis of VS,
do not use the osilloscope.
Please be measured using the tester.

Is the voltage
of CN5001 : 1 pin
approx. -25V ?

Replace D-AMP SUB ASSY

Check of the power supply circuit of D-AMP ASSY

Return to the 1) No sound

F

20

A-70-K

1

2 3 4

5

6 7 8

5.2 PROTECTION CIRCUIT DESCRIPTION

1. PROTECTION operation

Purpose of PROTECTION operation

 Protection of operation due to failure of product
 Protection of operation due to wrong use by a user

e.g.) Rare short of speaker connection is generated, or product is installed by

blocking the heat release hole

Detect the L/Rch independently for OVER LOAD, temperature and ZOBEL, and detect 2 ch
for the power PROTECTION (main unit side), and perform OR process by software.

1.1 DC DETECT

After DC DETECT is detected, MUTE ON & PROTECTION RELAY OFF are carried out.
If DC DETECT is detected for 3 seconds or more continuously, it is evaluated as "1.1.1 AMP failure" shown below.
If DC DETECT is detected for less than 3 seconds, it is evaluated as 1.1.2 SIGNAL CLIP" shown below.

1.1.1 AMP failure
After DC DETECT is detected, MUTE ON & PROTECTION RELAY OFF are carried out.

Prohibit the power is turned ON for 1 minute.
If DC DETECT is detected again when the power is turned ON next time, it is judged to be “AMP failure,”
and the power is turned OFF.
If the power supply is automatically turned OFF after AMP failure is detected, all key operations are
prohibited (Prohibit the power supply is turned ON).
For turning ON the power supply again, refer to “3. How to reset the prohibition of power ON” shown below.

1.1.2 SIGNAL CLIP
If DC DETECT is detected for less than 3 seconds, it is evaluated as "SIGNAL CLIP".
If the detection of DC DETECT is reset within 3 seconds, MUTE OFF & PROTECTION RELAY ON

are carried out.
NOTE) If the detection of DC DETECT is reset within 3 seconds and DC detection functions immediately,

PROTECTION RELAY OFF/ON is repeated, however, there is no problem.

A

B

C

1.2 OVER LOAD

MUTE ON & PROTECTION RELAY OFF are carried out immediately after the detection and the power is
turned OFF.
After OVER LOAD is detected, the key operation is not prohibited (the power supply can be turned ON).

NOTE) If a short of speaker cable may be generated, the connection is made again and the power supply

cannot be turned ON by a user, so a complaint is generated.
If AMP is broken actually, DC detection operates, so there is no problem.

1.3 Temperature PROTECTION

MUTE ON & PROTECTION RELAY OFF are carried out immediately after the detection and the power is
turned OFF.
Prohibit the power is turned ON for 1 minute.

NOTE) After the detection, if the temperature is still high even by turning ON the power supply,

the temperature PROTECTION is detected again and the power supply is turned OFF.

1.4 Power PROTECTION

MUTE ON & PROTECTION RELAY OFF are carried out immediately after the detection and the power is
turned OFF.

If the power supply is automatically turned OFF after the power PROTECTION is detected, all key operations are
prohibited (Prohibit the power supply is turned ON).

For turning ON the power supply again, refer to "3. How to reset the prohibition of power ON" shown below.

1.5 ZOBEL PROTECTION

MUTE ON & PROTECTION RELAY OFF are carried out immediately after the detection and the power is
turned OFF.
After ZOBEL is detected, the key operation is not prohibited (the power supply can be turned ON).

D

E

F

A-70-K

5

6 7 8

21

1

2 3 4

1.6 Power PROTECTION (D-AMP side)

MUTE ON & PROTECTION RELAY OFF are carried out immediately after the detection and the

A

power is turned OFF.
If the power supply is automatically turned OFF after the power PROTECTION is detected, all key operations
are prohibited (Prohibit the power supply is turned ON).
For turning ON the power supply again, refer to “3. How to reset the prohibition of power ON” shown below.

2. Keeping the prohibition of power is turned ON after 1.1.1 AMP failure is detected and

1.4 power PROTECTION is detected

If the power supply is automatically turned OFF after AMP failure is detected and power PROTECTION is detected,
all key operations are prohibited (Prohibit the power supply is turned ON).

The power supply is turned ON prohibition status is kept even if the backup is carried out and the power cord is

B

disconnected and inserted.
For turning ON the power supply again, refer to "3. How to reset the prohibition of power ON" shown below.

3. How to reset the prohibition of power ON

Press Front Key [ POWER AMP DIRECT ] + [ SPEAKER B ] at the same time for 2 seconds continuously.
The key prohibition mode after 1.1.1 AMP failure is detected and 1.4 power PROTECTION is detected is canceled
and the power is turned ON.

C

D

Temperature
Protection Off

Overload
Protection

DC DETECT
(first)

E

DC DETECT
( Can't power-on)

Power
Protection
( Can't power-on)

Zobel
Protection

Power
Protection(D-AMP)
( Can't power-on)

4. STANDBY LED display after PROTECTION is detected

Each PROTECTION operations above are identified by blinking timing of STANDBY LED.
The blinking of LED is continued until the power is turned ON again.

For the blinking specification of LED, refer to "Protect LED display specifications" shown below.

Protect LED display specifications

200ms

On

1TIME : 800mS

1CYCLE : 1.4S

On

Off

1TIME : 400mS

1TIME : 2S

1TIME : 2.4S

1TIME: 4.2S

1TIME : 3.2S

1TIME : 3.2S

F

22

1

2 3 4

A-70-K

5

5.3 IC INFORMATION

AUDIO SELECTOR(8-IN 4-OUT SSOP-32P)

6 7 8

NJW1112V

1/1

A

Pin Layout

Block Diagram

10μF

V-

+

VDDO UT

LATCHDATA CLOCK

Control Logic

32

17

B

611

V+

V-ADR

OutA1

+

+

100μF

100μF

26 25 2432 31 302928 27 19 18 1723 22 21 20

GND

10μF

10μF

10μF

+

+

OutA3

OutB2OutA2OutB1

10μF

10μF

10μF

+

+

+

OutB4OutA4OutB3

10μF

10μF

+

+

+

C

8 9 1 2 3 4 5 6 14 15 1610 11 12 13

7

Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin Rin

+

+ + + + + + + + + + + + + + +

InA1 InA2 4BnI4AnI1BnIInB3

InB2

InA3

InB6InA5 InA6 8BnI8AnI5BnIInB7

InA7

Pin Function

No. Pin Name Function No. Pin Name Function

1 InA1 Ach Input 1 17 OutB4 Bch Output 4
2 InB1 Bch Input 1 18 OutA4 Ach Output 4

3 InA2 Ach Input 2 19 OutB3 Bch Output 3
4 InB2 Bch Input 2 20 OutA3 Ach Output 3

5 InA3 Ach Input 3 21 OutB2 Bch Output 2
6 InB3 Bch Input 3 22 OutA2 Ach Output 2

7 InA4 Ach Input 4 23 OutB1 Bch Output 1
8 InB4 Bch Input 4 24 OutA1 Ach Output 1

9 InA5 Ach Input 5 25 V- V- Power Supply Terminal

10 InB5 Bch Input 5 26 GND Ground Terminal

11 InA6 Ach Input 6 27 V+ V+ Power Supply Terminal
12 InB6 Bch Input 6 28 ADR Chip address setting terminal

13 InA7 Ach Input 7 29 CLOCK CLOCK
14 InB7 Bch Input 7 30 LATCH LATCH

ATAD ATAD13 8 tupnI hcA 8AnI 51

16 InB8 Bch Input 8 32 VDDOUT Internal Digital Power Supply Output

D

E

F

A-70-K

5

6 7 8

23

1

2 3 4

1/1

NJW1194V

A

(2 CH VOLUME)

Pin Layout

B

Block Diagram

C

32

17

611

D

Pin Function

No. Pin Name Function No. Pin Name Function

E

F

24

A-70-K

1

2 3 4

Pin Layout

5

6 7 8

1/2

ES9011S-TRB

(DAC FROM PIONEER)

DVCC_T

VDD

DATA_CLK

DATA1

DATA2

GND

GND

GND

GND

GND

GND

GND

A

Block Diagram

4847464544434241403938

37

DAC1 1 36

DAC1B 2 35

GND 334
GND 4 33
GND 5 32

AVCC_L 6 31

RESET 7 30

GND 8 29
GND 9 28
GND 10 27
GND 11 26
GND 12 25

1314151617181920212223

XO

SCL

AVCC_L

SDA

GND

DVCC_B

XI (MCLK)

VDD

VDD

GND

GND

24

AVCC_R

DAC2
DAC2B
GND
GND
GND
AVCC_R
AUTOMUTE
GND
GND
GND
GND
VDD

B

C

D

DATA

DATA_CLK

SPDIF in

MCLK

5

DSD/PCM

Interface

SPDIF

Receiver

RESET

OVERSAMPLING FILTER

AUTOMUTE

CONTROL INTERFACE

Fast/Slow roll-off (PCM)

50/60/70kHz (DSD)

De-emphasis (PCM)

Volume Control

Soft Mute

Zero Detect

6 7 8

SCL

SDA

Jitter

Reduction

DPLL

POWER SUPPLY

DVCC

A-70-K

DGND

Hyperstream

Hyperstream

DAC

DAC

(8x)

(8x)

E

TM

TM

Dynamic

Matching

(8x)

VREF

DAC[2:1]

DACB[2:1]

AVCC

AGND

F

25

A

Pin Function

B

C

D

E

1

2 3 4

ES9011S-TRB

(DAC FROM PIONEER)

Pin Pin Name Type Function

1 DAC1 O Differential Pos itive Analog Output 1
2 DAC1B O Differential Negative Analog Output 1
3 GND - Digital Ground
4 GND - Digital Ground
5 GND - Digital Ground
6 AVCC_L - Analog Power (+3.3V) for Left channels
7 RESET I Global Reset
8 GND - Digital Ground

9 GND - Digital Ground
10 GND - Digital Ground
11 GND - Digital Ground
12 GND - Digital Ground
13 VDD - Digital Power (+1.2V) for core of chip
14 AVCC_L - Analog Power (+3.3V) for Left channels
15 GND - Digital Ground
16 SDA I/O I2C SDA
17 SCL I I2C SCL
18 XO O Xtal oscillator output
19 XI (MCLK) I Xtal oscillator input (Note: can also just be a clock input)
20 DVCC_B - Digital Power (+3.3V) for bottom pad ring of chip
21 VDD - Digital Power (+1.2V) for core of chip
22 GND - Digital Ground
23 GND - Digital Ground
24 AVCC_R - Analog Power (+3.3V) for Right channels
25 VDD - Digital Power (+1.2V) for core of chip
26 GND - Digital Ground
27 GND - Digital Ground
28 GND - Digital Ground
29 GND - Digital Ground

30 AUTOMUTE O Automute
31 AVCC_R - Analog Power (+3.3V) for Right channels
32 GND - Digital Ground
33 GND - Digital Ground
34 GND - Digital Ground
35 DAC2B O Differential Negative Analog Output 2
36 DAC2 O Differential Positive Analog Output 2
37 GND - Digital Ground
38 GND - Digital Ground
39 GND - Digital Ground

40 GND - Digital Ground
41 GND - Digital Ground
42 GND - Digital Ground
43 GND - Digital Ground

44 DATA2 I DSD Data2 OR PCM Data CH1/CH2
45 DATA1 I DSD Data1 OR PCM Frame Clock OR SPDIF Input
46 DATA_CLK I PCM Bit Clock OR DSD Bit Clock
47 VDD - Digital Power (+1.2V) for core of chip
48 DVCC_T - Digital Power (+3.3V) for top pad ring of chip

2/2

F

6. SERVICE MODE

There is no information to be shown in this chapter.

26

1

A-70-K

2 3 4

5

6 7 8

7. DISASSEMBLY

Note 1 : Even if the unit shown in the photos and illustrations in this manual may differ from your product, the procedures
described here are common.
Note 2 : As for the assembling, please perform assembling following to the opposite procedures of How to Disassemble.

If any notes are existed, please follow those instructions.

Note 3 : For performing the diagnosis shown below, the following jigs for service is required.

• 25P + 19P extension jig cable (GGD1830) ( A-70-K, A-70-S only)

Note 4 : Before starting the diagnosis, wait for three minutes until the electricity of the unit is discharged.

[1] Disassembly

[1-1] Exterior

[1-1-1] Top Cabinet, Side Panel

(Case of A-70-K, A-70-S)

(1) Remove the six screws, using the hex key

(2.5mm).
( A-70-K: CHD1A080FFZRP )
( A-70-S: CHD1A080FFCP )

(2) Remove the three screws.

(CTB3+6JFZR)

(3) Remove the Top Cabinet.

Notes on assembling

To attach the Top Cabinet, refer to the
“[3-4-2] Top Cabinet”.

Top Cabin et

1

1

1

1

1

3

1

2

2

2

A

B

C

(4) Remove the four screws, using the hex key

(2.5mm).
( A-70-K: CHD1A080FFZRP )
( A-70-S: CHD1A080FFCP )

(5) Remove the four screws.

(BBZ30P060FTC)

(6) Remove the Side Panel R and Side Panel L.

Notes on assembling

To attach the Side Panel, refer to the “[3-4-1]
Side Panel-R, Side Panel-L”.

5

4

5

4

6

Side Panel R

6

Side Panel L

5

D

4

5

E

4

F

A-70-K

5

6 7 8

27

1

[1-1-2] Top Cabinet

(Case of A-50-K, A-50-S, A-50)

(1) Remove the six screws, using the hex key

A

(2.5mm).
( A-50-K, A-50: CHD1A080FFZRP )
( A-50-S: CHD1A080FFCP )

(2) Remove the five screws.

(CTB3+6JFZR)

2 3 4

Top Cabinet

1

1

1

2

1

2

B

(3) Insert nails between the Top Cabinet and

Rear Panel and then pull the Top Cabinet
backward horizontally.

C

1

Top Cabinet

2

1

2

2

3

Insert nails

Rear Panel

D

(4) Take out Top Cabinet upward while spreading

Rear Side Piece.

E

F

Top Cabinet

4

While spreading

While spreading

28

A-70-K

1

2 3 4

5

6 7 8

[1-1-3] Rear Panel

(1) If Short Pin Plug is attached, remove it.
(2) Remove the two screws. (CTB4+10GFZR)
(3) Remove the four Cover Sheets and the four

screws. (CTB3+10JFZR)
(4) Remove the eight screws. (CTB3+8JFZR)
(5) Remove the screws. (CTB3+6JFZR)

(A-70-K, A-70-S: 15 screws)

(A-50-K, A-50-S, A-50: 13 screws)
(6) Remove the two screws.

(A-70-K, A-70-S only: BBZ30P060FTC)
(7) Remove the Rear Panel.

[Case of A-70-K, A-70-S]

:

4 5

x 8

:

6

1

1

[Case of A-50-K, A-50-S, A-50]

:

4 5

x 8

:

1

1

x 15

A

6

3

2

7

x 13

Rear Panel

B

3

2

C

7

Rear Panel

[1-2] SUB INPUT ASSY,
CONNECTOR ASSY,
PHONO ASSY, USB ASSY and
INPUT ASSY

Remove the Top Cabinet, Rear Panel and Side
Panel R.
(Refer to the “ [1-1] Exterior”. )

----------------------------------------------------------------­(1) Disconnect the connector and then remove

the SUB INPUT ASSY and CONNECTOR

ASSY.

(2) Remove the four screws.

(A-70-K, A-70-S only: BBZ30P060FTC)
(3) Remove the Side Frame.

(A-70-K, A-70-S only)
(4) Remove the screw.

(BBZ30P060FTC)

[Case of A-50-K, A-50-S, A-50]

PCB Bracket

4

CONNECTOR ASSY

BN32

[Case of A-70-K, A-70-S]

2

2

1

SUB INPUT ASSY

D

3

E

Side Frame

4

2

2

Bottom Chassis

Bottom Chassis

A-70-K

5

6 7 8

F

29

1

(5) Disconnect the connector.
(6) Disconnect the two connectors and then

A

remove the PHONO ASSY (with the PCB
Blacket).

2 3 4

6

PHONO ASSY

BN14

BN15

CN95

INPUT ASSY

PCB Bracket

B

(7) Release the 19P FFC from the PCB binder.
(8) Disconnect the two connectors.
(9) Remove the two screws.

(BBZ30P060FTC)

(10) Disconnect the three connectors and then

remove the USB ASSY.

C

D

19P FFC

25P FFC

7

8

USB ASSY

5

BN96

9

BN81

10

Center Frame R

BN13

9

BN12

BN11

(11) Disconnect the two connectors.
(12) Remove the screw. (CHD2A060R)
(13) Remove the four screws.

E

F

(BBZ30P060FTC)

(14) Remove the INPUT ASSY.

30

1

Front

CN4000 CN4200

11

13

12

14

INPUT ASSY

13

Front

A-70-K

2 3 4

13

13