Yamaha GA 011589 User Manual

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ACOUSTIC GUITAR PRE-AMPLIFIER

SERVICE MANUAL

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

011589

GA

CONTENTS

SPECIFICATIONS ................................................ 3/4

PANEL LAYOUT .................................... 5

BLOCK DIAGRAM

CIRCUIT BOARD LAYOUT ............... 10

WIRING ................................................................... 11

DISASSEMBLY PROCEDURE ............................ 12

LSI PIN DESCRIPTION .............................. 15

IC BLOCK DIAGRAM ................................... 18

CIRCUIT BOARDS ........................................ 20

TEST PROGRAM ................................. 28

ERROR MESSAGES ............................. 32

MIDI IMPLEMENTATION CHART......................................... 33

PARTS LIST
OVERALL CIRCUIT DIAGRAM

1.507K-926 Printed in Japan 2001.7

............................ 8

HAMAMATSU, JAPAN

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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 per-

IMPORTANT : This presentation or sale of this manual to any individual or firm does not constitute authorization certifi-

The data provided is belived to be accurate and applicable to the unit(s) indicated on the cover. The research engineering, and
service departments of Yamaha are continually striving to improve Yamaha products. Modifications are, therefore, inevitable
and changes in specification are subject to change without notice or obligation to retrofit. Should any 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

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

IMPOR TANT NOTICE

sonal 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.

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

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

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 between 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 and must be replaced with parts having specification equal to those
originally installed.

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SPECIFICATIONS

Digital Section

• Full Digital Signal Processing

• Mic Simulator: 8 Types

• Feedback Reduction: 5-band

• Digital Effects

• Limiter

• Digital Chorus, Digital Delay

• Hall Reverb, Room Reverb, Plate Reverb

• External Controller Function (EXP Pedal/MIDI): 8 Controllers/
Parameters

• Tuner Function (Chromatic, Auto)

MIDI Functions

Receive: Program Change (Progr am Change Table can be cre­ated), Control Change, Bulk In
Transmit: Program Change, Control Change, Bulk Out, Merge
Out

Guitar Power Supply

9V power can be supplied via a TRS phone cab le to a guitar’s
built-in pre-amplifier, etc. that consumes less than 10mA of
power, and uses a monaural output.

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Connections

INPUT: Standard Stereo Phone Jack
OUTPUT L/MONO, R: Standard Stereo Phone Jack (TRS Bal
anced)
PHONES: Standard Stereo Phone Jack
EXP. PEDAL: Standard Stereo Phone Jac k
DIGITAL OUT: COAXIAL
MIDI IN, MIDI OUT: 5-pin DIN

A/D Converter

20 bit

D/A Converter

20 bit

Sampling Frequency

44.1kHz

Memory Allocations

Preset: 30
User: 30

Controller/Switch

Top Panel

Push Switch x17

UP, DOWN, MANUAL, UTILITY, STORE, LIMITER, FEED
BACK REDUCTION 1-5, CHORUS , DELA Y, HALL, ROOM,
PLATE, SHIFT

Knob x15

MIC TYPE, BLEND, VOLUME, BASS, MIDDLE, TREBLE,
PRESENCE, LIMITER LEVEL, FEEDBACK REDUCTION
FREQ, FEEDBACK REDUCTION DEPTH, CHORUS
SPEED/DELAY TIME, CHORUS DEPTH/DELAY FEED
BACK, CHORUS LEVEL/DELAY LEVEL, REVERB LEVEL,
OUTPUT

Footswitch x4

1, 2, 3 BANK

Rear Panel

STAND-BY ON/OFF, MUTE, +9V SUPPLY ON/OFF

Display

7 Segment LED (3 digit) x1
Push Switch LED x17
Footswitch LED x4

Input Level/Impedance
(When using pre-amp bypass)

INPUT: -17dBm/1MΩ

Output Level/Impedance

OUTPUT L/MONO: Balance +4dBm/600Ω
OUTPUT R: Balance +4dBm/600Ω
PHONES: 0dBm/47Ω

Power

Exclusive Power Adaptor (AC-10)
AC Output: AC12V, 1A

Power Consumption

15W

Dimensions

280(W)x70(H)x184(D)mm (11.0"x2.8"x7.2")

Weight

2.2 kg (4lbs. 4oz.)

Accessories

Power Adaptor (AC-10)
TRS Phone Cable for Guitar Power Supply (3m)
TRS-XLR Converter Cable (x2)
Dummy Battery

Owner’s Manual

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4

PANEL LAYOUT

Top Panel

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Display & Main Section

Effect Section

Pre-Amplifier Section

Display & Main Section

q
w

y

Foot Switch Section

e
r
t

UP Button

1

DOWN Button

2

MANUAL Button

3

UTILITY Button

4

STORE Button

5

Display

6

5

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Pre-AmpSection

u i o !0

MIC TYPE Select Switch (MIC TYPE)

7

BLEND Control (BLEND/STEREO)

8

VOLUME

9

Tone Controls

10

OUTPUT Level Control

11

SHIFT Button

12

!2

!1

Effect Section

!4 !6 !7 !9 @0 @1 @3

LIMITER Button

13

LEVEL

14

Feedback Reduction Buttons

15

Frequency Control (FREQ)

16

DEPTH Control

17

CHORUS/DELAY Effect Buttons

18

SPEED/TIME Control

19

DEPTH/FEEDBACK Control

20

LEVEL

21

Reverb Effect Buttons

22

REVERB V olume

23

!5

!8 @2!3

6

Footswitch Section

Footswitches 1, 2, 3

24

Bank Switch (AUTO F.R./BANK/TUNER)

25

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@4 @5

Rear Panel

@6 @7 @8 #0 #1 #2 #3 #5#6

Power Switch (STAND-BY ON/OFF)

26

Power Adaptor Jack (AC IN 12V 1A)

27

Guitar Power Supply Switch

28

MIDI OUT Jack

29

MIDI IN Jack

30

Digital Output Jack (DIGITAL OUT)

31

EXP. PEDAL Jack

32

Headphone Jack (PHONES)

33

Output Jacks (OUTPUT R, L/MONO)

34

INPUT Jack

35

Input MUTE Switch

36

#4@9

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N

BLOCK DIAGRAM

DM

A

2/2

1
3

7
4
2

PN

1/2

DM

IC101

3

W101

W102

IC1X2

AN0~AN3,SELECT-A,SELECT-B

1/2

1

(

DM1/2-CN3

(

PN1/2-CN302

)

)

IC102

21

IC2,IC3

IC102

67

X1

PN 1/2

CN301CN101

5
6
3
4

IC104

IC8

DOUT

16

IC12

PB0~PB7,SW-R0~R3

26

27

IC10,IC11

(

DM1/2-CN1

(

PN1/2-CN304

)

)

CN301 C

PN 2/2

A'

8

PN 1/2

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A

CN3011

CN301 CN101

IC106

1

3

IC103

1

3

LED-FOOT, SW-001
LED-REV, SW-010
LED-MOD
SW-100, SW-LINE

IC105

5

IC105

3

IC106

-1
6

IC103

6

(

DM1/2-CN2

(

PN1/2-CN303

7

1

7

7

)

)

2
3
1

2
3
1

2
3
1

2
3
1

OUTPUT

OUTPUT

RXDO,TXDO

15,17

PN 2/2

IC112, IC113, IC114

KEC-54233

A'

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CIRCUIT BOARD LAYOUT

2/2DM

PN

1/2

DM

1/2

PN

2/2

10

1/2

2/2

(V611470)

(V610850)

(V611460)

(V611450)

CN301

CN304

CN1 CN2 CN3

CN310 CN309

CN308

CN307

CN303

CN101

W101

W102

CN302 CN305

CN306

(V611480)

PN

2/2

1/2

DM

DM

PN

Note) When installing the DM circuit board, use care not to
have the wire assembly caught by the bottom case.

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WIRING

CNB-V698560 1

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DISASSEMBLY PROCEDURE

1. Bottom Case (Manhour requirement: 5 min.)

Remove the six (6) screws marked [30]. The bottom
case can then be removed. (Fig. 1)

Bottom

[30]:Bind Head Tapping Screw-B 3.0x8 MFZN2BL (EP600190)

2. DM Circuit Board (Manhour requirement: 15 min.)

2-1. Remove the bottom case. (See Procedure 1.)
2-2. DM1/2 Circuit Board (Manhour requirement: 10 min.)

Remove the one (1) screw marked [T110A], three
(3) screws marked [T120], four (4) hexagonal nuts
marked [T50A] and four (4) flat washers marked
[T60A] from the rear panel and the three (3) screws
marked [T110B] from the DM1/2 circuit board. The
DM1/2 circuit board can then be removed. Remove
the four (4) toothed washer internal tooth forms
marked [T70] as well when removing the DM1/2
circuit board from the main body. (Fig. 2)

2-3. DM2/2 Circuit Board (Manhour requirement: 5 min.)

Remove the one (1) hexagonal nut marked [T50B]
and one (1) flat washer marked [T60B]. The DM2/2
circuit board can then be removed.

[30]

[30]

Fig.1

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Rear

[T110A] [T50A][T60A] [T50B][T60B]

[T50]:Hexagonal Nut 9.0 12x2 MFNI33 (LX200060)
[T60]:Flat Washer 9x14 0.5 FNM3 (VL802300)
[T120]:Bind Head Tapping Screw-P 3.0x12 MFZN2BL (VC161100)

[T120]

Topcover

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[T70]

2/2DM

1/2DM

[T110B]

[T70]:Washer 9.0 MFZN2Y (ET800150)
[T110]:Bind Head Tapping Screw-B 3.0x8 MFZN2BL (EP600190)

Fig.2

3. PN Circuit Boards (1/2, 2/2)

(Manhour requirement: 20 min.)

3-1. Remove the bottom case. (See Procedure 1.)
3-2. Remove the DM1/2 and DM2/2 circuit boards. (See

Procedure 2.)

3-3-1. PN 1/2 Cir cuit Board (Manhour requirement: 10 min.)

Remove the controls, knobs and hexagonal nuts
from the front panel, the three (3) screws marked
[T110] and the shield film from the PN1/2 circuit
board. The PN1/2 circuit board can then be remov ed.
(Fig. 3)

3-3-2. PN 2/2 Circuit Boar d (Manhour requirement: 5 min.)

Remove the f our (4) hexagonal n uts and the f our (4)
flat washers marked [T80] from foot switches. The
PN 2/2 circuit board can then be removed. (Fig. 3)

PN

[T110]

1/2

[T110]

shield film

[T80]

Hexagonal Nut

[T80]

Hexagonal Nut

[T80]:Flat Washer 12x17 0.5 MFNI33 (V7407400)
[T110]:Bind Head Tapping Screw-B 3.0x8 MFZN2BL (EP600190)

Fig.3

2/2PN

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4. Heat Sink (Manhour requirement: 25 min.)

4-1. Remove the bottom case. (See Procedure 1.)
4-2. Remove the DM circuit board. (See Procedure 2.)
4-3. Remove the two (2) screws marked [A-a] from the

soldered face of the DM circuit board and the three
(3) screws marked [A-b] from IC112, IC113 and
IC114. The heat sink can then be removed from the
DM circuit board. (Fig. 4)

Heat Sink

[A-a]

IC114

IC113

IC112

Fig.4

[A-b]

[A-a]

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