Yamaha MG10/2 User manual

SERVICE MANUAL
SPECIFICATIONS（総合仕様）............................................... 3/5
DIMENSIONS（寸法図）........................................................... 7
PANEL LAYOUT（パネルレイアウト）...................................... 8
CIRCUIT BOARD LAYOUT & WIRING
（ユニットレイアウト＆結線図）.............................................. 11
DISASSEMBLY PROCEDURE（分解手順）............................. 12
IC BLOCK DIAGRAM（ICブロック図）.................................. 14
CIRCUIT BOARD（シート基板図）.......................................... 15
INSPECTIONS（検査）....................................................... 17/21
PARTS LIST
BLOCK DIAGRAM & LEVEL DIAGRAM
（ブロックダイアグラム＆レベルダイアグラム）
OVERALL CIRCUIT DIAGRAM（総回路図）
■CONTENTS（目次）
HAMAMATSU, JAPANHAMAMATSU, JAPAN
Copyright (c) Yamaha Corporation. All rights reserved. PDF-K344 ’05.08
011780
200306-14800
PA
MIXING CONSOLE
A manufacture number should use this
manual with goods of 9 or more figures.
（本マニュアルは、製造番号が9桁以上の商
品でご使用ください。）
The example of a manufacture number.
（製造番号例）
JCLJ01001
UCCLJ01001
CHNCL01001
9-11 figures
（9〜11桁）
The service manual of PA 011679 should
be used for the goods whose manufacture
number is 7 figures.
（製造番号が7桁の商品は、PA011679の
サービスマニュアルをご使用ください。）
The example of a manufacture number.
（製造番号例）
LK01001
7figures
（7桁）

2
MG10/2
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 believed 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.
■WARNING
Components having special characteristics are marked and must be replaced with parts having specification equal to
those originally installed.
印の部品は、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。
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 markings 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.

MG10/2
3
Frequency Characteristics (ST OUT) 20 Hz-20 kHz +1 dB, -3 dB @+4 dBu, 10 kΩ(with gain control at maximum level)
Total Harmonic Distortion (ST OUT) 0.1 % (THD+N) @+14 dBu, 20 Hz-20 kHz, 10 kΩ(with gain control at maximum level)
(CHs 1 and 2)
-128 dBu Equivalent input noise (CHs 1 and 2)
-100 dBu Residual output noise (ST OUT)
Hum and Noise 1-87 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)
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)
Maximum Voltage Gain 276 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)
+/-15 dB
Monaural/Stereo Input Channel Equalization: HIGH 10 kHz shelving
Max. Variation 3MID 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.
Two 12-point LED meters [Stereo (L, R)]
Level Meters 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)
USA and Canada: 120 V AC, 60 Hz
Europe: 230 V AC, 50 Hz
Power Supply Australia: 240 V AC, 50 Hz
Korea: 220 V AC, 60 Hz
China: 220 V AC, 50 Hz
Power Consumption 19 W
Max. Dimensions (W x H x D) 251 x 65 x 290.5 mm
Weight 1.8 kg
■General Specifications
1Measured with 12.7 kHz, -6 dB/oct. low pass filter (equivalent to 20 kHz, -∞filter).
(CH MIC INPUT to ST, AUX, EFFECT SEND)
2Turning PAN/BAL to left or right.
3Shelving turnover/rolloff frequency: 3 dB before maximum cut or boost.
Where 0 dBu = 0.775V and 0 dBV = 1 V
■SPECIFICATIONS

4
MG10/2
Input Connector Gain Input
Impedance
Appropriate
Impedance Sensitivity* Rated Level Max. Before Clipping
Connector
Specifications
MIC INPUT
(CH 1-2)
–60
3 k
Ω 50–600 Ω mic
–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 k
Ω 600 Ω line
–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)
–60
3 k
Ω 50–600 Ω mic
–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))
ST CH MIC INPUT
(CH3/CH4/CH5/CH6)
–34
10 k
Ω 600 Ω line
–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 k
Ω 600 Ω line –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 k
Ω 600 Ω line –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 k
Ω 600 Ω line –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 k
Ω 600 Ω line –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
Ω 10 k Ω line +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
Ω 10 k Ω line +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
Ω 10 k Ω line 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
Ω 10 k Ω line –10 dBV (316 mV) +10 dBV (3.16 V) RCA pin jack
C-R OUT (L, R) 150
Ω 10 k Ω line +4 dBu (1.23 V) +20 dBu (7.75 V)
Phone jack (TRS)
(impedance balanced [T: hot; R: cold; S:
ground])
PHONES 100
Ω 40 Ω phone 3 mW 75 mW Stereo phone jack
■Input Specifications
■Output Specifications
Where 0 dBu = 0.775V and 0 dBV = 1 V
* Input sensitivity: the lowest level that will produce the nominal output level when the unit is set to maximum gain.
Where 0 dBu = 0.775V and 0 dBV = 1 V

MG10/2
5
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kHz、10kΩ（GAINコントロール＝最大レベル）
(CH1、2)
-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
ハム&ノイズ*1 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)
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)
最大電圧ゲイン*2 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)
+/-15dB
モノラル、ステレオ入力チャンネルイコライザー HIGH10kHzシェルビングタイプ
特性最大可変幅*3 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
12ポイントLED×2［ステレオ（L、R）］
レベルメーター 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） 251×65×290.5mm
質量 1.8kg
*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
＊ 0dBu=0.775V、0dBV=1Vとする
■一般仕様
■総合仕様

6
MG10/2
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 –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))
(CH3/CH4/CH5/CH6)
–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
■入力仕様
■出力仕様
＊ 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
＊ 0dBu=0.775V、0dBV=1Vとする

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

8
MG10/2
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
5
6
7
[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
[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
■PANEL LAYOUT（パネルレイアウト）
●Master Control Section（マスターコントロール部）
●Channel Control Section（チャンネルコントロール部）

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）

10
MG10/2
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
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
＊
Connector Polarities
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。
*
These jacks will also accept connection to monaural phone plugs. If you use monaural plugs, the connection will be unbalanced.

MG10/2
11
MAIN
Power switch and AC connector wiring
（電源スイッチとACコネクタの結線）
(a). Twist Wiring Assy AC8 three times,and fix to a top cover.
 束線AC8を3回捻り、トップカバーに固定します。

(b). Adjust the position so that the wire is arranged within the range
of the PWB print (reticulation).
 線材が、基板印刷(網目)の範囲内に配置されるように位置を調整します。

(c). Fix the wire by pasting the filament tape to the position of figure.
 図の位置にフィラメントテープを貼り、線材を固定します。

* Note that the wire (black) doesn't shut the hole that tightens the screw.
 この時、線材(黒)が､ネジ締め穴を塞がないように注意してください。

Top Cover
WA595401 (Connector
3P BROWN, RED, BLACK )
(c) VA126400 (Filament Tape)
（熱収縮チューブ：7箇所）
WB071100 (Shrink Tube Black : 7 places)
V3272800 (Cord Holder)
(a) WD350000 (Connector Assembly AC8 3P BROWN, RED, BLACK)
* Hole of Screw
(b) Reticulation
（網目）
WE521400 (MAIN circuit board)
• Rear view
• Top view • Right side view
■CIRCUIT BOARD LAYOUT & WIRING（ユニットレイアウト&結線図）

12
MG10/2
[250]: Hex. Socket Screw-P（Pタイト6角孔付き）3X25 MFZN2B3 (WF419200)
[260]: Bind Head Tapping Screw-B（Bタイト＋BIND）3.0X8 MFZN2B3 (WE774400)
[270]: Bind Head Tapping Screw-S（Sタイト＋BIND）3.0X6 MFZN2B3 (WE877800)
[280]: Bonding Tapping Screw-B（Bタイト＋BOND）3.0X10 MFZN2B3 (WE878000)
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
•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)
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）
■DISASSEMBLY PROCEDURE（分解手順）

MG10/2
13
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)
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 Remove the meter cover from the MAIN circuit
board. (Fig. 1)
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. 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)
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）

14
MG10/2
NJM4558M (TE1) (X5676A00)
MAIN: IC103, 304, 404, 503, 603
Dual Operational Amplifier
NJM4556AL (XP844A00)
MAIN: IC806
Dual Operational Amplifier
LB1412M (X5838A00)
MAIN: IC803, 805
LED Driver
NJM2068M-D (TE2) (X3505A00)
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
2 3 4 5 6 7 8
OUT
A
-IN
A
+IN
A
+IN
B
-IN
B
OUT
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
V
CC
I LED
OSC
V
Z
6
8
9
10
11
13
14
15
16
17
12
■IC BLOCK DIAGRAM（ICブロック図）

MG10/2
15
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
■CIRCUIT BOARD（シート基板図）
•MAIN 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（部品側）
2NA-WE52140

16
MG10/2
•MAIN Circuit Board
Pattern side（パターン側）
2NA-WE52140

MG10/2
17
1. Measurement conditions
1-1. Environment
Normal temperature (10 to 35C)
Normal humidity (45 to 85%)
1-2. Power Source
The voltage is within +/-10%.
AC Adaptor (PA-10) shall be used.
WC703600 (H,W:230V) or WC703500 (U,V:120V), WC703700 (B:230V), WC703800 (K:220V), WC703900 (A:240V),
WC711000 (O:220V)
2. Electric characteristics
2-1. Preparation
The load resistances for each output terminals are as follows,
PHONES (L/ R): 40 ohms
Others: 10 kohms
2-2. Unless otherwise specified, the operation elements shall be set as follows,
•CH (1-2) INPUT
GAIN control MAX(-60dBu)
80 switch OFF
EQ (HIGH, MID, LOW) level control CENTER
AUX level control PRE(turned counterclockwise fully)
PAN control L(turned counterclockwise fully)
CH LEVEL VR MAX
•ST CH (3/4, 5/6)
GAIN control MIC:MAX(-60dBu)
80 switch OFF
EQ (HIGH, MID, LOW) level control CENTER
AUX level control PRE(turned counterclockwise fully)
PAN/BAL control L(turned counterclockwise fully)
CH LEVEL VR MAX
•ST CH (7/8, 9/10)
EQ (HIGH, MID, LOW) level control CENTER
AUX level control PRE(turned counterclockwise fully)
BAL control L(turned counterclockwise fully)
CH LEVEL VR MAX
•MASTER control
RETURN to ST level control MAX
2TR IN to ST level control MAX
C-R/PHONES level control MAX
ST Master VR MAX
•Others
PHANTOM switch OFF
2-3. Unless otherwise specified, the input signal shall be 1kHz sine wave.
2-4. The input signal impedance shall be 150 ohms.
2-5. Indicator Inspection
POWER LED shall light when the unit is turned on.
■INSPECTIONS

18
MG10/2
INPUT INPUT Level Gain INSERT OUT REC OUT L REC OUT R
1,2
Mic 1, 2 -72 Max ––
CH INSERT IN 1 0 Unspecified –
CH INSERT IN 2 0 Unspecified ––
INPUT INPUT CH INPUT Level Gain ST L OUT ST R OUT AUX1 AUX2
Mic -72 Max
-28 Min –––
PHONE JACK 3,5L -46 Max –
4,6R –
Table 2.6.3 Input Terminal STEREO IN [dBu]
w
e
r
INPUT INPUT CH INPUT Level
INPUT Level
INPUT Level
ST L OUT ST R OUT AUX1 AUX2
PHONE JACK 7L,9L
8R,10R -22
PIN JACK 7L,9L
8R,10R
Table 2.6.4 Input Terminal STEREO IN [dBu]
t
y
u
i
INPUT ST L OUT ST R OUT
L/MONO -8
R–
Table 2.6.5 Input Terminal RETERN L,R [dBu]
o
!0
INPUT ST L OUT ST R OUT C-R OUT L C-R OUT R PHONES L PHONES R
L-35.8 ––
R––
Table 2.6.6 Input Terminal 2TR IN L,R [dBu]
!1
!2
Table 2.6.2 [dBu]
–
–
––
––
–
–
+1 +/-2 *1
0 +/-2 *1 0 +/-2 *1
+1 +/-2 *1
+1 +/-2 *1 +1 +/-2 *2
-12 +/-2
+4.2 +/-2 +4.2 +/-2
+4.2 +/-2
+1 +/-2
+1 +/-2
+7 +/-2 *2
+7 +/-2 *2
-5 +/-2
+4 +/-2
+4 +/-2
+4 +/-2
+4 +/-2
-2 +/-2 +4 +/-2 *2
+4 +/-2 +4 +/-2
+4 +/-2
+4 +/-2
+4 +/-2
-12 +/-2
-12 +/-2
–
–
-7.5 +/-2
-7.5 +/-2
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 +5 +/-2 *20 +/-2 *1 +16 +/-2 *1 +16 +/-2 *1-1 +/-2
0 +/-2 *1
+1 +/-2 *1-28 Min –––– –
Line -46 Max –––– –
Table 2.6.1 CH INPUT(1, 2) [dBu]
q
2-7. Frequency Characteristics
In the signal routes of the Table 2.6.1 to 2.6.6 indicated with 1to B, 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 1, 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 4, check only the ST L OUT and the ST R OUT.
* 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.
The deference in the level between channels shall be 2dB or less.
2-6. Gain
The output levels shall be within the range specified in the Table 2.6.1 to 2.6.6.

MG10/2
19
EQ control EQ GAIN Applied frequency Variation width
HI MAX 10kHz
MIN
MID MAX 2.5kHz
MIN
LO MAX 100Hz
MIN
Table 2.9.1 [dB]
+12 +/-2
-12 +/-2
+12 +/-2
-12 +/-2
+15 +/-2
-15 +/-2
INPUT PEAK LED
MIC
Table 2.11.1 [dBu]
-43 +/-2
2-8. HPF
In the state of the Table 2.6.1 and 2.6.2, 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 -3dB +/-2dB compared to the level obtained when the
switch is set to OFF.
2-9. Channel Equalizer Characteristics
In the state checked in 2-2. 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 2.9.1 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 of Table 2.9.1.
2-10. Crosstalk
Setting the VR to the nominal position, and turning the PAN control (PAN/BAL or 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 (PAN/BAL, BAL) 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.
2-11. PEAK LED light-up level
Each LED shall light-up within the range specified in the table 2.11.1 when a signal is fed to the MIC input.
2-12. 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”.
2-13. Distortion Factor
In the signal routes of the Table 2.6.1 to 2.6.6 indicated with 1to B(except 3, 4), set the VR 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 1, 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 2, 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.

20
MG10/2
VR STEREO OUT AUX OUT C-R OUT
MAX -81.0 -85.0 -87.0
MIN -100.0 – -93.0
Table 2.16.1 [dBu]
2-14. Maximum Output
In the state 2-2., 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 PAN/BAL, BAL Control to L or R fully respectively.
In measuring the C-R OUT and PHONES, set the C-R/PHONE Control to MAX.
2-15. Equivalent Input Noise
In the state 2-2., connect between the CH INPUT MIC terminals (2pin-Hot and 3pin-Cold) with 150 ohms, the noise
level obtained at ST L OUT shall be less than -51.5dBu.
If it is over than -51.5dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less
than -127.5dBu.
Connect between the ST INPUT MIC terminals (2pin-Hot and 3pin-Cold) with 150 ohms, the noise level obtained at ST
L OUT shall be less than -47.5dBu.
If it is over than -47.5dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less
than -124dBu.
(Noise is measured with a 12.7kHz -6dB/octave low pass filter.)
2-16. Residual Noise
In the state 2-2., 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 2.16.1.
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.
(Noise is measured with a 12.7kHz -6dB/octave low pass filter.)
2-17. PHANTOM
Connect a 10 kΩload 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.