Yamaha MG10/2 User manual

MG10/2
1
SERVICE MANUAL
PA 011679
200306-14800 Copyright (c) Yamaha Corporation. All rights reserved. PDF-K135 ’03.04
HAMAMATSU, JAPAN
CONTENTS
SPECIFICATIONS ................................................ 3/5
DIMENSIONS ............................................................ 7
PANEL LAYOUT ..................................... 8
CIRCUIT BOARD LAYOUT & WIRING
............................................ 11
DISASSEMBLY PROCEDURE ............................ 12
IC BLOCK DIAGRAM .................................. 14
CIRCUIT BOARD ......................................... 15
INSPECTIONS ....................................................... 17/21
PARTS LIST
BLOCK DIAGRAM & LEVEL DIAGRAM
OVERALL CIRCUIT DIAGRAM
（ 総合仕様 ）
（
寸法図 ）
（パネルレイアウト）
（ユニットレイアウト＆結線図）
（分解手順）
（ICブロック図）
（シート基板図）
（検査）
（ブロックダイアグラム＆レベルダイアグラム）
（総回路図）
（目次）
MIXING CONSOLE

MG10/2
2
IMPORTANT NOTICE
This manual has been provided for the use of authorized Yamaha Retailers and their service personnel. It has been assumed
that basic service procedures inherent to the industry, and more specifically Yamaha Products, are already known and under-
stood 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-
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.
IMPORTANT : This presentation or sale of this manual to any individual or firm does not constitute authorization certifi-
cation, recognition of any applicable technical capabilities, or establish a principal-agent relationship of
any form.
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
accumulated by grounding yourself to the ground bus in the unit (heavy gauge black wires connect to
this bus.)
IMPORTANT : Turn the unit OFF during disassembly and parts replacement. Recheck all work before you apply power
to the unit.
WARNING: CHEMICAL CONTENT NOTICE!
The solder used in the production of this product contains LEAD. In addition, other electrical/electronic and/or plastic (Where
applicable) components may also contain traces of chemicals found by the California Health and Welfare Agency (and possibly
other entities) to cause cancer and/or birth defects or other reproductive harm.
DO NOT PLACE SOLDER, ELECTRICAL/ELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH FOR ANY REASON WHAT
SO EVER!
Avoid prolonged, unprotected contact 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.
IMPORTANT NOTICE FOR THE UNITED KINGDOM
Connecting the Plug and Cord
IMPORTANT. The wires in this mains lead are coloured in accordance with the following code:
BLUE : NEUTRAL
BROWN : LIVE
As the colours of the wires in the mains lead of this apparatus may not correspond with the coloured makings identifying the terminals in your
plug proceed as follows:
The wire which is coloured BLUE must be connected to the terminal which is marked with the letter N or coloured BLACK.
The wire which is coloured BROWN must be connected to the terminal which is marked with the letter L or coloured RED.
Making sure that neither core is connected to the earth terminal of the three pin plug.
WARNING
Components having special characteristics are marked and must be replaced with parts having specification equal to those
originally installed.
印の商品は、安全を維持するために重要な部品です。交換する場合は、安全のために必ず指定の部品をご使用ください。

MG10/2
3
SPECIFICATIONS
General Specifications
Where 0 dBu = 0.775 V and 0 dBV = 1 V
1
Measured with 12.7 kHz, –6 dB/oct. low pass filter (equivalent to 20 kHz, –∞filter).
(CH MIC INPUT to ST, AUX, EFFECT SEND)
2
Turning PAN/BAL to left or right.
3
Shelving turnover/rolloff frequency: 3 dB before maximum cut or boost.
Frequency Characteristics (ST OUT) 20 Hz–20 kHz +1 dB, –3 dB @+4 dBu, 10 k
Ω (with gain control at maximum level)
Total Harmonic Distortion (ST OUT) 0.1 % (THD+N) @+14 dBu, 20 Hz–20 kHz, 10 k
Ω (with gain control at maximum level)
(CHs 1 and 2)
Hum and Noise
1
–128 dBu Equivalent input noise (CHs 1 and 2)
–100 dBu Residual output noise (ST OUT)
–87 dBu (91 dB S/N) ST, Master fader at nominal level and all Ch at minimum
level.
–85 dBu (89 dB S/N) All channel mix controls at minimum level.
–64 dBu (68 dB S/N) ST, Master fader and one Ch fader at nominal level.
(CHs 1 and 2)
Maximum Voltage Gain
2
60 dB CH MIC INPUT → CH INSERT OUT
76 dB CH MIC INPUT → ST OUT
64.2 dB CH MIC INPUT → REC OUT
70 dB CH MIC INPUT → AUX SEND1 (PRE)
76 dB CH MIC INPUT → AUX SEND2 (POST)
76 dB ST CH MIC INPUT → ST OUT
50 dB ST CH LINE INPUT → ST OUT
41 dB ST CH LINE INPUT → AUX SEND1 (PRE)
47 dB ST CH LINE INPUT → AUX SEND2 (POST)
26 dB ST CH INPUT → ST OUT
12 dB AUX RETURN → ST OUT
23.8 dB 2TR INPUT → ST OUT
Monaural/Stereo Input Gain Control 44 dB variable
Monaural/Stereo High Pass Filter 80 Hz 12 dB/octave
Crosstalk (1 kHz) –70 dB between input channels
–70 dB between input/output channels (CHs 1 to 6)
Monaural/StereoInputChannelEqualization:
Max. Variation
3
±15 dB
HIGH 10 kHz shelving
MID 2.5 kHz peaking
LOW 100 Hz shelving
Monaural/Stereo Input Peak Indicator On each channel: red indicator lights if post-EQ signal (on ST channels, if either post-EQ sig-
nal or post-mic-amp signal) comes within 3 dB of the clipping level.
Level Meters
Two 12-point LED meters [Stereo (L, R)]
Peak point: red indicator
+5, +3, +1, and 0 points: yellow indicators
–1, –3, –5, –7, –10, –15, –20: green indicators
Phantom +48 VDC Power (Balanced input) Supplied when Phantom +48 V switch is ON.
Included Accessory Power adaptor (PA-10)
Option Microphone-stand adaptor (BMS-10A)
Power Supply
USA and Canada: 120 V AC, 60 Hz
Europe: 230 V AC, 50 Hz
Australia: 240 V AC, 50 Hz
Korea: 220 V AC, 60 Hz
Power Consumption 19 W
Max. Dimensions (W
× H × D) 251
1.8
× 65 × 290.5 mm
Weight kg

MG10/2
4
Input Specifications
Where 0 dBu = 0.775 V and 0 dBV= 1V
* Input sensitivity: the lowest level that will produce the nominal output level when the unit is set to maximum gain.
Output Specifications
Where 0 dBu = 0.775 V and 0 dBV= 1 V
Input Connector Gain Input
Impedance Appropriate Impedance Sensitivity* Rated Level Max. Before Clipping Connector Specifications
MIC INPUT
(CH 1-2)
–60 3 kΩ50–600 Ωmic
–72 dBu
(0.195 mV) –60 dBu (0.775 mV) –40 dBu (7.75 mV) XLR-3-31 type (balanced)
–16 –28 dBu
(30.9 mV) –16 dBu (123 mV) +4 dBu (1.23 V)
LINE INPUT
(CH 1, 2)
–34 10 kΩ600 Ωline
–46 dBu
(3.88 mV) –34 dBu (15.5 mV) –14 dBu (155 mV) Phone jack (TRS)
(balanced [T: hot; R: cold;
S: ground])
+10 –2 dBu
(0.616 V) +10 dBu (2.45 V) +30 dBu (24.5 V)
ST CH MIC INPUT
(CH3/CH4,CH5/CH6)
–60 3 kΩ50–600 Ωmic
–72 dBu
(0.195 mV) –60 dBu (0.775 mV) –40 dBu (7.75 mV) XLR-3-31 type (balanced)
–16 –28 dBu
(30.9 mV) –16 dBu (123 mV) –10 dBu (245 mV)
ST CH LINE INPUT
(CH3(L)/CH4(R),
CH5(L)/CH6(R))
–34 10 kΩ600 Ωline
–46 dBu
(3.88 mV) –34 dBu (15.5 mV) –14 dBu (155 mV) Phone jack (unbalanced)
+10 –2 dBu
(0.616 V) +10 dBu (2.45 V) +30 dBu (24.5 V)
ST CH INPUT
(CH7(L)/CH8(R),
CH9(L)/CH10(R)) 10 kΩ600 Ωline –22 dBu
(61.6 mV) –10 dBu (245 mV) +10 dBu (2.45 V) Phone jack (unbalanced); RCA pin jack
CH INSERT IN
(CH 1, 2) 10 kΩ600 Ωline –20 dBu (77.5 mV) 0 dBu (0.775 V) +20 dBu (7.75 V) Phone jack (TRS)
(unbalanced [T: out; R: in;
S: ground])
AUX RETURN (L, R) 10 kΩ600 Ωline –12 dBu
(195 mV) +4 dBu (1.23 V) +24 dBu (12.3 V) Phone jack (TRS) (unbalanced [T: hot; S: ground])
2TR IN (L, R) 10 kΩ600 Ωline –26 dBV
(50.1 mV) –10 dBV (316 mV) +10 dBV (3.16 V) RCA pin jack
Output Connectors Output
Impedance Appropriate Impedance Rated Level Max. Before Clipping Connector Specifications
ST OUT (L, R) 150 Ω10 kΩline +4 dBu (1.23 V) +20 dBu (7.75 V) Phone jack (TRS)
(impedance balanced [T: hot; R: cold; S:
ground])
AUX SEND (1, 2) 150 Ω10 kΩline +4 dBu (1.23 V) +20 dBu (7.75 V) Phone jack (TRS) (impedance balanced [T: hot; R: cold; S:
ground])
CH INSERT OUT (CH 1, 2) 150 Ω10 kΩline 0 dBu (0.775 V) +20 dBu (7.75 V) Phone jack (TRS)
(unbalanced [T: out; R: in; S: ground])
REC OUT (L, R) 600 Ω10 kΩline –10 dBV (316 mV) +10 dBV (3.16 V) RCA pin jack
C-R OUT (L, R) 150 Ω10 kΩline +4 dBu (1.23 V) +20 dBu (7.75 V) Phone jack (TRS) (impedance balanced [T: hot; R: cold; S:
ground])
PHONES 100 Ω40 Ωphone 3 mW 75 mW Stereo phone jack

MG10/2
5
総合仕様
一般仕様
＊ 0 dBu = 0.775 V、
0 dBV = 1 V とする
*1 Rs = 150 ohms
@12.7 kHz、 –6 dB/oct. のローパスフィルターにて測定
（
@20 kHz、 –∞dB/oct.フィルターに相当）
（
CH MIC INPUT to ST、 AUX、 EFFECT SEND）
*2 PAN/BAL 左か右へ回す
*3 シェルビングタイプのターンオーバー/ロールオフ周波数：最大可変幅に対し3 dB下がったポイント
周波数特性（ST OUT）
20 Hz 〜 20 kHz +1 dB, –3 dB 
@
+4 dBu（＊）、 10 kΩ（ GAIN コントロール＝最大レベル）
全高調波歪率（ST OUT）
0.1 %（ THD+N） @ +14 dBu, 20 Hz 〜 20 kH、 10 kΩ（ GAIN コントロール＝最大レベル）
(CH1、 2)
ハム& ノイズ
*1
–128 dBu 入力換算ノイズ(CH1、
2)
–100 dBu 残留ノイズ
(ST OUT)
–87 dBu（ 91 dB S/N）ST マスターコントロール＝ノミナル、
全チャンネルコントロール＝最小レベル
–85 dBu（ 89 dB S/N）
全チャンネルミックスコントロール＝最小レベル
–64 dBu（ 68 dB S/N）ST マスターコントロール＆1チャンネルコントロール＝ノミナ
ル(CH1、
2)
最大電圧ゲイン
*2
60 dB  CH MIC INPUT → CH INSERT OUT
76 dB  CH MIC INPUT → ST OUT
64.2 dB  CH MIC INPUT → REC OUT
70 dB  CH MIC INPUT →AUX SEND1（ PRE）
76 dB  CH MIC INPUT → AUX SEND2（ POST）
76 dB  ST CH MIC INPUT →ST OUT
50 dB  ST CH LINE INPUT →ST OUT
41 dB  ST CH LINE INPUT →AUX SEND1（ PRE）
47 dB  ST CH LINE INPUT → AUX SEND2（ POST）
26 dB  ST CH INPUT →ST OUT
12 dB  AUX RETURN →ST OUT
23.8 dB  2TR INPUT →ST OUT
モノラル、ステレオインプットゲインコントロール 44 dB 可変
モノラル、ステレオハイパスフィルター 80 Hz 12 dB/octave
クロストーク
(1 kHz) –70 dB 入力チャンネル間
–70 dB 入出力チャンネル間(CH1〜6)
モノラル、ステレオ入力チャンネルイコライザー
特性最大可変幅
*3
±15 dB
HIGH 10 kHz シェルビングタイプ
MID 2.5 kHz ピーキングタイプ
LOW 100 Hz シェルビングタイプ
モノラル、ステレオインプットピークインジケーター
各チャンネル、イコライザー（およびMIC アンプ：
ST CH）の後段において、どちらか
一方の信号レベルがクリッピングの手前3 dB に達すると赤く点灯
レベルメーター
12 ポイントLED ×2 ［ステレオ（ L、 R）］
ピーク時：赤のインジケーター
+5、 +3、 +1、 0：黄のインジケーター
–1、 –3、 –5、 –7、 –10、 –15、 –20：緑のインジケーター
ファンタム電源+48 VDC（バランス入力） PHANTOM +48 V スイッチ＝ON で供給
付属品 電源アダプター
(PA-10)
オプション マイクスタンドアダプター（
BMS-10A）
電源 100 V AC 50/60 Hz
消費電力 19 W
最大外形寸法（
W×H×D） W251 ×H65 ×D290.5 mm
質量 1.8 kg

MG10/2
6
入力仕様
＊ 0 dBu=0.775 V、
0 dBV=1 V とする
*1
入力感度：最大ゲイン測定時に定格出力が得られる最小レベル
出力仕様
＊ 0 dBu=0.775 V、
0 dBV=1 V とする
入力端子名称 ゲイン 入力イン
ピーダンス
適合インピーダンス 感度
*1
規定レベル 最大ノンク
リップレベル 端子仕様
MIC INPUT
(CH1-2）
–60 3 kΩ
50 〜600 Ωマイク–72 dBu
（
0.195 mV）
–60 dBu （
0.775 mV）–40 dBu
（
7.75 mV） XLR-3-31タイプ
（バランス型）
–16 –28 dBu
（
30.9 mV）
–16 dBu （
123 mV） +4 dBu
（
1.23 V）
LINE INPUT
(CH1、 2) –34 10 kΩ
600 Ωライン –46 dBu
（
3.88 mV）
–34 dBu （
15.5 mV）–14 dBu
（
155 mV） フォーンジャック
（
TRS） （バランス
型［
T：ホット、
R: コールド、
S：グラウンド］）
+10 –2 dBu
（
0.616 V）
+10 dBu （
2.45 V） +30 dBu
（
24.5 V）
ST CH MIC INPUT
(CH3/CH4、 CH5/CH6) –60 3 kΩ
50 〜600 Ωマイク–72 dBu
（
0.195 mV）
–60 dBu （
0.775 mV）–40 dBu
（
7.75 mV） XLR-3-31タイプ
（バランス型）
–16 –28 dBu
（
30.9 mV）
–16 dBu （
123 mV） –10 dBu
（
245 mV）
ST CH LINE INPUT
(CH3(L)/CH4(R)、
CH5(L)/CH6(R))
–34 10 kΩ
600 Ωライン –46 dBu
（
3.88 mV）
–34 dBu （
15.5 mV）–14 dBu
（
155 mV） フォーンジャック
（アンバランス型）
+10 –2 dBu
（
0.616 V）
+10 dBu （
2.45 V） +30 dBu
（
24.5 V）
ST CH INPUT
(CH7(L)/CH8(R)、
CH9(L)/CH10(R))
10 kΩ
600 Ωライン –22 dBu
（
61.6 mV）
–10 dBu （
245 mV） +10 dBu
（
2.45 V） フォーンジャック
（アンバランス型）、

RCA ピンジャック
CH INSERT IN
(CH1、 2) 10 kΩ
600 Ωライン –20 dBu
（
77.5 mV）
0 dBu （
0.775 V） +20 dBu
（
7.75 V） フォーンジャック
（
TRS）
（アンバランス型
［
T：アウト、 R：イ
ン、
S：グラウンド］

）

AUX RETURN (L、 R) 10 kΩ
600 Ωライン –12 dBu
（
195 mV）
+4 dBu （
1.23 V） +24 dBu
（
12.3 V） フォーンジャック
（
TRS）（アンバラ
ンス型［
T: ホット、

S: グラウンド］）
2TR IN (L、 R) 10 kΩ
600 Ωライン –26 dBV
（
50.1 mV）
–10 dBV （
316 mV） +10 dBV
（
3.16 V）
RCA ピンジャック
出力端子名称 出力インピーダンス適合インピーダンス 規定レベル
最大ノンクリップレベル
端子仕様
ST OUT (L、 R)
150 Ω 10 kΩライン +4 dBu（
1.23 V） +20 dBu（ 7.75 V）
フォーンジャック（
TRS）
（インピーダンスバランス型
［
T：ホット、 R:コールド、
S: グラウンド］）
AUX SEND (1、 2) 150 Ω
10 kΩライン +4 dBu（
1.23 V） +20 dBu（ 7.75 V）
フォーンジャック（
TRS）
（インピーダンスバランス型
［
T：ホット、 R:コールド、
S: グラウンド］）
CH INSERT OUT
(CH1、 2) 150 Ω
10 kΩライン 0 dBu（
0.775 V） +20 dBu（ 7.75 V） フォーンジャック（ TRS）
（アンバランス型［
T: アウト、

R：イン、 S: グラウンド］）
REC OUT (L
、
R) 600 Ω
10 kΩライン –10 dBV（
316 mV）+10 dBV（ 3.16 V） RCAピンジャック
C-R OUT (L
、
R) 150 Ω
10 kΩライン +4 dBu（
1.23 V） +20 dBu（ 7.75 V）
フォーンジャック（
TRS）
（インピーダンスバランス型
［
T：ホット、 R:コールド、
S: グラウンド］）
PHONES 100 Ω
40 Ωフォーン 3 mW 75 mW ステレオフォーンジャック

MG10/2
7
DIMENSIONS
Units: mm
（単位）
（寸法図）
251
290.5
65

MG10/2
8
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
5
6
7
Channel Control Section
[GAIN] Control
[PEAK] Indicator
[ 80 ] Switch (High Pass Filter)
Equalizer ([HIGH], [MID], and [LOW])
[AUX] Controls
[PAN] Control (CHs 1 and 2)
[PAN/BAL] Control (CHs 3/4 and 5/6)
[BAL] Control (CHs 7/8 and 9/10)
Channel Fader
PANEL LAYOUT
[PHANTOM +48 V] Switch
[RETURN] Control
[2TR IN] Control
[ST] Master Fader
[C-R/PHONES] Control
Level Meter
[POWER] Indicator
[PHANTOM+48V]スイッチ
[RETURN]コントロール
[2TRIN]コントロール
[ST]マスターコントロール
[C‐R/PHONES]コントロール
レベルメーター
[POWER]インジケーター
Channels
1 and 2
(Monaural)
Channels
3/4 and 5/6
(Stereo)
Channels
7/8 and 9/10
(Stereo)
1
2
3
4
5
6
7
[GAIN]コントロール
[PEAK]インジケーター
[80]（ハイパスフィルター）スイッチ
イコライザー（[HIGH]、[MID]、[LOW]）
[AUX]コントロール
[PAN]コントロール（CH1、2）
[PAN/BAL]コントロール（CH3/4、5/6）
[BAL]コントロール（CH7/8、9/10）
チャンネルコントロール
（チャンネルコントロール部）
（パネルレイアウト）
Master Control Section
（マスターコントロール部）

MG10/2
9
1
2
3
4
5
6
7
8
9
10
Channel Input Jacks (CHs 1, 2, 3/4, 5/6)
[INSERT I/O] Jacks (CHs 1, 2)
Channel Input Jacks (CHs 7/8, 9/10)
[2TR IN] Jacks
[REC OUT] (L, R) Jacks
[ST OUT] (L, R) Jacks
[C-R OUT] Jacks
[SEND] Jacks
[RETURN] L (MONO), R Jacks
[PHONES] Jack
1
2
3
4
5
6
7
8
9
10
チャンネルINPUT端子（CH1、2、3/4、5/6）
[INSERTI/O]端子（CH1、2）
チャンネルINPUT端子（CH7/8、9/10）
[2TRIN]端子
[RECOUT]（L、R）端子
[STOUT]（L、R）端子
[C‐ROUT]端子
[SEND]端子
[RETURN]L（MONO）、R端子
[PHONES]端子
1
2
1
2[AC ADAPTOR IN] Connector
POWER Switch
[ACADAPTORIN]端子
電源スイッチ
Input/Output Section（入出力部）
Rear Section
（リア部）

MG10/2
10
Connector Polarities
* These jacks will also accept connection to monaural phone plugs. If you use monaural plugs, the connection will be unbalanced.
MIC INPUT Pin 1: Ground
Pin 2: Hot (+)
Pin 3: Cold (–)
LINE INPUT (monaural channels),
ST OUT, C-R OUT,
AUX1, AUX2*
Tip: Hot (+)
Ring: Cold (–)
Sleeve: Ground
INSERT I/O Tip: Output
Ring: Input
Sleeve: Ground
PHONES Tip: L
Ring: R
Sleeve: Ground
RETURN,
LINE INPUT (stereo channels) Tip: Hot Sleeve: Ground
INPUT OUTPUT
Ring
Sleeve Tip
Sleeve Tip
端子接続の極性
＊これらの端子に、モノラルタイプのフォーン端子を使用することもできます。その場合は、アンバランスになります。
MIC INPUT ピン1：グラウンド
ピン
2：ホット（ +）
ピン
3：コールド（ –）
LINE INPUT（モノラルチャンネル）、
ST OUT、 C-R OUT
AUX 1、 AUX 2 
＊
チップ：ホット（
+）
リング：コールド（
–）
スリーブ：グラウンド
INSERT I/O チップ：
Output
リング：
Input
スリーブ：グラウンド
PHONES チップ：
L
リング：
R
スリーブ：グラウンド
RETURN
LINE INPUT （ステレオチャンネル） チップ：ホット
スリーブ：グラウンド
INPUT OUTPUT
スリーブ チップ
リング
スリーブ チップ

MG10/2
11
CIRCUIT BOARD LAYOUT & WIRING
MAIN
（ケーブルの色）
Power switch and AC connector wiring
（電源スイッチとACコネクタの結線）
(V975620) (Connector assembly 2P BROWN, RED)
Need twist of one rotation.
V9737300 (MAIN circuit board) V998150
(Connector assembly 3P
BROWN, RED, BLACK)
Cable Colors Need twist of
one rotation.
Wiring to MAIN circuit board
（MAINシートへの結線）
Cable Tie（ケーブルの結び方）
Shrink Tube（熱収縮チューブのつけ方）
（熱収縮チューブ：7箇所）
（1回ひねります。）
（1回ひねります。）
（基板のハンダ面にハンダ付けします。）
（電源スイッチの配線は左に45°の向きで取り付け、
白い斜線の部分から出ないように配線します。）
（束線を左に引っぱった状態でインシュロックタイを止めます。）
RED
BLACK
RED
BROWN
BROWN
RED
WB071100 (Shrink tube: Seven places) VV104600 (Cable Tie)
Bundle the four cables connected to power switch
by the cable tie and pull to left side.
When soldering a wire, it fixed in the state
that inclined to the left about 45 degrees,
and it wires so that it may not be from white
slash area of circuit board.
(V998150) is soldering on solder side.
Rear view
Top view Right side view
（ユニットレイアウト＆結線図）

MG10/2
12
DISASSEMBLY PROCEDURE
[250]: Hex. Socket Tapping Screw-P 3X25 MFZNBL (V3289800)
[260]: Bind Head Tapping Screw-B 3.0X8 MFZN2BL (EP600190)
[270]: Bind Head Tapping Screw-S 3.0X6 MFZN2BL (EP630210)
[280]: Bonding Tapping Screw-B 3.0X8 MFZN2BL (VN413300)
1. ボトムケース（所要時間：約 1 分）
1-1 [250]のネジ 5 本と[260]のネジ 2 本を外し、ボトム
ケースを外します。（図 1）
Fig .1(図1)
[260]
[250]
[250] [250]
[250]
[250]
[260]
[270]
[280]
Hexagonalnutx21
（特殊六角ナット）
PushHPFbuttonx4
（ボタンHPF） PushPFLbutton
（ボタンPFL）
Metercover
（ウィンドウMETER）

Topcover
（トップカバー）
[280] [280] [280] [280]
[ A ] [ A ]
[ B ] x30
[ B ] x4
[ B ] x2
ACsupport
（サポートAC）
ACconnector
（ACコネクター）
Powerswitch
（電源スイッチ） Bottomcase
（ボトムケース）
MAIN
（6角孔付きボタンPタイト）
Rear view
Top view
1. Bottom Case (Time required: About 1 minute)
1-1 Remove the five (5) screws marked [250] and the
two (2) screws marked [260].The bottom case can
then be removed.(Fig. 1)
（分解手順）
（＋バインドBタイト）
（＋バインドSタイト）
（ボンディングBタイト）

MG10/2
13
2. サポート AC（所要時間：約 2 分）
2-1 ボトムケースを外します。（1 項参照）
2-2 [270]のネジ1本を外し、サポートACを外します。
（図 1、写真 1）
3. MAIN シート（所要時間：約 8 分）
3-1 ボトムケースを外します。（1 項参照）
3-2 サポート AC を外します。（2項参照）
3-3 [280]のネジ 10 本と特殊六角ナット 21 個、[A]のノ
ブ（LEVEL）8個を外し、MAINシートを外します。
（図1）
※MAINシート上のノブ、ボタン、ウィンドウMETER
は、シートの構成部品ではありません。MAINシー
トを交換する際は、以下の手順でこれらの部品を取
り外してください。
3-4 MAIN シートから[B]のノブ（VR）36 個とボタン
（HPF）4個、ボタン（PFL）1個を外します。（図1）
3-5 MAIN シートからウィンドウ METER を外します。
（図 1）
4. 電源スイッチとACコネクター（所要時間：各約2分）
4-1 ボトムケースを外します。（1 項参照）
4-2 サポート AC を外します。（2項参照）
4-3 電源スイッチのツメを曲げて、サポートACから電
源スイッチを外します。（写真 2）
4-4 特殊六角ナット1個と平ワッシャー1個を外して、サ
ポートACからACコネクターを外します。（写真2）
2. AC Support (Time required: About 2 minutes)
2-1 Remove the bottom case.(See procedure 1.)
2-2 Remove the screw marked [270].The AC support
can then be removed. (Fig. 1, Photo. 1)
3. MAIN Circuit Board
(Time required: About 8 minutes)
3-1 Remove the bottom case.(See procedure 1.)
3-2 Remove the AC support. (See procedure 2.)
3-3 Remove the ten (10) screws marked [280], the
twenty-one (21) hexagonal nuts and the eight (8)
level knobs marked [A].The MAIN circuit board can
then be removed.(Fig. 1)
The knobs, buttons and meter cover on the MAIN
circuit board are not components of the circuit
board. When replacing the MAIN circuit board,
be sure to remove these parts according to the
following procedure.
3-4 Remove the thirty-six (36) volume knobs marked [B],
the four (4) push HPF buttons and the push PFL
button from the MAIN circuit board.(Fig. 1)
3-5 Removethe metercoverfrom theMAIN circuitboard.
(Fig. 1)
4. Power Switch and AC Connector
(Time required: About 2 minutes each)
4-1 Remove the bottom case.(See procedure 1.)
4-2 Remove the AC support. (See procedure 2.)
4-3 Remove the power switch by bending its claw from
the AC support. (Photo.2)
4-4 Remove the hexagonal nut and the flat washer.The
AC connector can then be removed from the AC
support. (Photo. 2)
ACsupport
（サポートAC）
Claw
（ツメ）
Claw
（ツメ）
ACconnector
（ACコネクター）
Hexagonalnut
andflatwasher
（特殊六角ナット
と平ワッシャー）
Powerswitch
（電源スイッチ）

ACsupport
（サポートAC）
Photo.2 (写真2)Photo.1 (写真1)

MG10/2
14
IC BLOCK DIAGRAM
NJM4558M (T1)(IG103520)
MAIN: IC103, 304, 404, 503, 603
Dual Operational Amplifier
NJM4556AL
MAIN: IC806
Dual Operational Amplifier
(XP844A00)
LB1412M (XT547A00)
MAIN: IC803, 805
LED Driver
NJM2068MD-T1 (XJ553A00)
MAIN: IC202, 302, 303, 402, 403, 501, 502,
601, 602, 701, 702, 802
NJM4580ED (XT157A00)
MAIN: IC101, 201, 301, 401, 801, 804
Dual Operational Amplifier
13
10
9
8
16
7
6
5
4
3
2
23
22
21
20
19
18
17
14 1512
11
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
OSC
CURENT
DRIVER
CURENT
DRIVER
VZ
OUT2
RESET OSC ILED
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
IN2
OUT1
IN1
VCC
GND
R
SQ
R
SQ
Q
R
SQ
Q
R
SQ
Q
R
SQ
Q
1
2
3
4-V
8
7
6
5
Output A +V
Non-Inverting
Input A
-DC Voltage Supply
+DC Voltage
Supply
Output B
Inverting
Input B
Non-Inverting
Input B
Inverting
Input A
+-
+-
1
2
3
4-V
8
7
6
5
Output A +V
Non-Inverting
Input A
Ground
+DC Voltage
Supply
Output B
Inverting
Input B
Non-Inverting
Input B
Inverting
Input A
+-
+- 1
A
2345678
OUT
A-IN A+IN A+IN B-IN BOUT B
-V +V
-
+
B
-
+
1NC
2
3
4
5
7
D8
D9
D10
D11
D12
IN1
OUT1
IN2
OUT2
RESET
GND 18
19
20
21
22
23
24 NC
D7
D6
D5
D4
D3
D2
D1
VCC
ILED
OSC
VZ
6
8
9
10
11
13
14
15
16
17
12
（IC ブロック図）

MG10/2
15
MAIN Circuit Board
CIRCUIT BOARD
Note: See parts list for details of circuit board component parts.
注：シートの部品詳細はパーツリストをご参照ください。
Component side
MIC 12
12
12
7 L
8 R
9 L
10 R
3/4 5/6
3 L
(MONO) 5 L (MONO)
4 R 6 R
L
(MONO)
R
AUX1
(PRE)
AUX2
PHONES
SENDRETURN
7 L
8 R
9 L
10 R
L
R
L
ST OUT C-R OUT
R
L
R
L
R
LINE
INSERT I/O
GAIN
PEAK PEAK
PEAK PEAK
HPF
HIGH
MID
LOW
AUX
PAN
LEVEL
1 2 3/4 5/6 7/8 9/10
PAN/BAL PAN/BAL BAL BAL
PHANTOM
+48V
L
PEAK
+5
+3
+1
0
-1
-3
-5
-7
-10
-15
-20
R
POWER
RETURN
2TR IN
ST
ST
C-R/PHONES ST
（シート基板図）
（部品側）

MG10/2
16
Pattern side
MAIN Circuit Board
（パターン側）

17
MG10/2
INSPECTIONS
1. Scope
This inspection specification is applied to the mixer MG10/2.
2. Power Supply
AC Adaptor shall be used.
V981040(H:230V 50Hz) or V981030(U:120V 60Hz), V981220(B:230V 50Hz), V981680(K:220V 60Hz),
V986200(A:240V 50Hz)
3. Power Indicator Inspection
POWER LED shall light when the unit is turned on.
4. Mixer Section Inspection
4.1 Preparation
The load resistances for each output terminals are as follows,
PHONES (L/ R): 40 ohms
Others: 10 kohms
Unless otherwise specified, the operation elements shall be set as follows,
•CH (1-2) INPUT
H•P•F switch OFF
GAIN Trim MAX(-60dBu)
HI, MID, LO EQ Gain control CENTER
AUX Level control PRE(turned counterclockwise fully)
PAN control L(turned counterclockwise fully)
CH VR MAX
•ST CH (3/4, 5/6, 7/8, 9/10)
GAIN Trim MIC: MAX(-60dBu)
LINE: MAX(-34dBu)
HI, MID, LO EQ Gain control CENTER
AUX Level control PRE(turned counterclockwise fully)
BAL control L(turned counterclockwise fully)
CH VR MAX
•MASTER control
STEREO Master VR MAX
AUX RETURN Level control MAX
2TR IN Level control MAX
C-R/PHONES Level control MAX
•Others
PHANTOM switch OFF
4.2 Gain
The output levels shall be within the range specified in the Table 4.2.1-4.2.6.
1 Measure with the PAN control set at the center position. For others, turn the PAN control counterclockwise fully for the
ST L and turn it clockwise fully for the ST R.
2 Measure with the AUX Level control set at the POST (turn the AUX Level control clockwise fully) position.
INPUT INPUT Gain ST L OUT ST R OUT AUX1 AUX2 C-R OUT L C-R OUT R
Level
Mic -72 Max 0 ±2 *1 0 ±2 *1 -1 ±2 +5 ±2 *2 +16 ±2 *1 +16 ±2 *1
-28 Min +1 ±2 *1 – – – – –
Line -46 Max 0 ±2 *1 – – – – –
Table 4.2.1 CH INPUT(1, 2) [dBu]
q

MG10/2
18
INPUT INPUT Level Gain INSERT OUT REC OUT L REC OUT R
1-4/8
Mic 1, 2 -72 Max -12 ±2– –
CH INSERT IN 1 0 Unspecified – +4.2±2+4.2±2
CH INSERT IN 2 0 Unspecified – +4.2±2–
Table 4.2.2 [dBu]
INPUT INPUT CH INPUT Level Gain ST L OUT ST R OUT AUX1 AUX2
Mic -72 Max 0±2 *1 0±2 *1 +1±2+7±2 *2
-28 Min +1±2 *1 – – –
PHONE JACK 3,5L -46 Max +1±2 *1 – +1±2+7±2 *2
4,6R – +1±2 *1 -5±2+1±2 *2
Table 4.2.3 Input Terminal STEREO IN [dBu]
w
e
r
4.3 Frequency Characteristics
In the signal routes of the Table 4.2.1 to 4.2.6 indicated with qto !2, the 20Hz and 20kHz frequency response of each
output shall be within the range of 0 dB +1/ -2.5 dB compared to the 1kHz (0dB).
The 20Hz level when the GAIN volume is Max shall be within the range of 0 dB +1.0/ -4.5 dB compared to the 1kHz (0dB).
In the route q, check every OUT when the signal is fed to CH1, and check only the ST L OUT when the signal is fed to
CH2 and other channels.
In the route r, check only the ST L OUT and the ST R OUT.
4.4 HPF
In the state of the Table 4.2.1 and 4.2.2, feeding 80 Hz -36dBu signal, and setting the GAIN to MIN, the STEREO L OUT
level obtained when the 80 switch is set to ON shall be within the range of -3 dB +2/ -2 dB compared to the level obtained
when the switch is set to OFF.
INPUT INPUT CH INPUT Level ST L OUT ST R OUT AUX1 AUX2
PHONE JACK 7,9L +4±2– -2±2+4±2 *2
8,10R -22 –+4±2
PIN JACK 7,9L +4±2–
8,10R – +4±2
Table 4.2.4 Input Terminal STEREO IN [dBu]
t
y
u
i
INPUT INPUT Level ST L OUT ST R OUT
L/MONO -8 +4±2+4±2
R–+4±2
Table 4.2.5 Input Terminal RETERN L,R [dBu]
o
!0
INPUT INPUT Level ST L OUT ST R OUT C-R OUT L C-R OUT R PHONES L PHONES R
L-35.8 -12±2–+4±2 – -7.5±2–
R – -12±2– +4±2 – -7.5±2
Table 4.2.6 Input Terminal 2TR IN L,R [dBu]
!1
!2

19
MG10/2
4.5 Channel Equalizer Characteristics
In the state checked in 4.2 above, check the output level obtained at ST L OUT in the case of CH INPUT and ST CH INPUT
L and at ST R OUT in the case of ST CH INPUT R when LO, HI and MID of INPUT are moved respectively.
Its level of each frequency shall be within the range specified in the table 4.5.1 compared to the output level obtained when
the EQ gain control is center click position.
If it is without the range, search the frequency, within the range of ±20%, of that the level is within the range ofTable 4.5.1.
4.6 Crosstalk
Setting the VR to the nominal position, and turning the PAN control (BAL control in the case of ST CH INPUT)
counterclockwise fully, the level of the leakage to ST R OUT shall be -50dBu or less when the output level of ST L OUT is
+20dBu.
Also turning the PAN control clockwise fully, the level of the leakage to ST L OUT shall be -50dBu or less when the output
level of ST R OUT is +20dBu.
In measuring the CH7 to CH10, the level of the leakage to ST OUT shall be -34dBu or less.
4.7 PEAK LED light-up level
In the state 4.1, each LED shall light-up when a signal specified as below is fed to the MIC input.
4.8 Meter LED lighting check
PEAK LED lights up, when ST output level reaches +17.5±2dBu.
0 LED lights up, when ST output level reaches +4±2dBu.
Operate the MASTER VR and check that LED light up in order from “-20” to “PEAK”.
4.9 Distortion Factor
In the signal routes of theTable 4.2.1 to 4.2.6 indicated with qto !2 (except e, r), set theVR of INPUT and MASTER to
the Nominal Position, and set the GAIN to the position specified in the Table (except PHONES).
Then, feeding each 20Hz, 1kHz and 20kHz signal, the distortion shall be less than 0.1%, when the output signal level is
+14dBu.
At the C-R OUT (L/ R), setting the Level Control to the 12 o’clock position, feeding each 20Hz, 1kHz and 20kHz signal, the
distortion shall be less than 0.2%, when the output signal level is +3dBu.
In the route q, check every OUT when the signal is fed to CH1, and check only the ST L OUT when the signal is fed to
CH2 and other channels.
In the route w, turning the PAN/BAL control to L fully, the distortion shall be less than 0.1%, when the ST L OUT signal
level is +4dBu.
EQ control EQ GAIN Applied frequency Variation width
HI MAX 10kHz +12±2
MIN -12±2
MID MAX 2.5kHz +15±2
MIN -15±2
LO MAX 100Hz +12±2
MIN -12±2
Table 4.5.1 [dB]
INPUT PEAK LED
MIC -43±2
Table 4.7.1 [dBu]

MG10/2
20
4.10 Maximum Output
In the state 4.9, the distortion factor shall be less than 1% when the output level is +20dBu at ST L OUT, ST R OUT, AUX1
OUT, AUX2 OUT and C-R OUT.
The distortion factor shall be less than 1% when the output level is +7.5dBu at PHONES (L/R).
In measuring the ST L OUT, the ST R OUT, set the PAN or BAL Control to L or R fully respectively.
In measuring the C-R OUT and PHONES, set the C-R/PHONE Control to MAX.
4.11 Equivalent Input Noise
In the state 4.1, shunt the CH INPUT MIC terminal with 150 ohms, the noise level obtained at ST L OUT shall be less than -52dBu.
If it is over than -52dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less than -128dBu.
Shunt the ST INPUT MIC terminal with 150 ohms, the noise level obtained at ST L OUT shall be less than -48dBu.
If it is over than -48dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less than -124dBu.
4.12 Residual Noise
In the state 4.1, set the Level Control of all input CH to MIN.
Then when the MASTER VR set to the MAX or MIN position, the noise level shall be less than the level specified in the
Table 4.12.1.
When measuring the AUX OUT, set the all CH AUX Level control to CENTER.
When measuring the C-R OUT and the PHONES, set the ST VR to MIN.
4.13 Phase
In the state 4.1, the phase of the input signal and the output signal shall be the same.
But the INSERT OUT signal shall be the reverse.
When a signal is fed to the INSERT IN, the phase of the output signal shall be the reverse.
4.14 PHANTOM
Connect a 10kΩload resistance between the pin 1 and 2 of the MIC and short-circuit between the pin 2 and 3.
Turn on the PHANTOM switch (LED shall light) and the voltage between pin 1 and 2 shall be within +35±3V.
4.15 Stability
Shunt the output terminal with the capacitance of 10pF-0.1microF respectively.Then, the unit shall not oscillate.
Shunt the all input terminals with 150 ohms, and set the all VR and EQ Control to MAX.
Then, the unit shall not oscillate.
4.16 Primary Voltage Tolerance
The unit shall work normally with the primary voltage of ±10%.
VR STEREO OUT AUX OUT C-R OUT
MAX -81.0 -85.0 -87.0
MIN -100.0 –-93.0
Table 4.12.1 [dBu]