Yamaha MS-400 Service Manual

MS400

POWERED SPEAKER

MS400

SERVICE MANUAL

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

011556

20001210-98000

SPECIFICATIONS ................................................... 3

DIMENSIONS ........................................................... 4

BLOCK DIAGRAM

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

CIRCUIT BOARD LAYOUT ................. 6

WIRING ..................................................................... 7

DISASSEMBLY PROCEDURE .............................. 8

IC BLOCK DIAGRAM ................................... 10

CIRCUIT BOARDS ........................................ 11

INSPECTIONS ............................................................ 16

OVERALL CIRCUIT DIAGRAM ........................... 19

PARTS LIST

1.415K-215 K Printed in Japan 2000.12

............................ 4

HAMAMATSU, JAPAN

MS400

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 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

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.

SPECIFICATIONS

General speciﬁcations

Type

Amp.unit

HF:100W at 5kHz, THD=1%, RL=16 ohms

Bi-Amp 2-way bass reflex powered speaker (Bi-amp lifier electronic crossover network))

Speaker unit

LF : 38 cm cone

HF : 5 cm Titanium diaphragm compression driver

Frequency Range .................. 50 Hz~16 kHz (-10 dB)

Maximum Output Level .......... 124.5 dB (1m on Axis)

Directional angle .................... 90˚ (H)/40˚ (V)

Dimension (W x H x D) .......... 449 x 683 x 379 mm

Weight ................................... 24.2 kg

Color ...................................... Black (approx.Munsell value:

5PB 2/1)

Tripod diameter pole .............. 35~36 mm

Accessories ........................... Power cord (AC inlet type, 2.5 m)

Maximum Output Power

LF: 300W at 500Hz, THD=1%, RL=4 ohms

Cross over frequency ............. 1.6 kHz (30dB/oct.)

Input Sensitivity ...................... LINE: +4dB*, MIC: -50dB*

Input impedance ..................... LINE: 30 kohms, MIC: 5 kohms

Controls

LEVEL .............. LINE, MIC , MASTER

EQ .................... LOW: 0 (Max.) ~ -10 dB (Min.) at 55 Hz

HIGH: ±3 dB (HF)

Power switch ........................ On/Off

Connectors (all balanced):

LINE in/out ................... XLR-3-31, XLR-3-32, phone

(They are all connected in parallel and can be used as line outputs.)

MIC in .......................... XLR-3-31

POWER indicator ................ Green LED

Power Requirement USA and Canada ...... 120 V, 60 Hz

Europe ....................... 230 V, 50 Hz

Others ........................ 240 V, 50 Hz

Power Consumption ............. 120 W

Accessor ies ......................... Bracketadapter BAD251 (for

BWS251-400, BCS251, and BBS251)

* 0 dB=0.775 V

For European Model Purchaser/User Information specified in EN55103-1 and EN55103-2. Inrush Current: 25A Conformed Environment: E1, E2, E3 and E4

MS400

DIMENSIONS

241

Remove the cover when you

use optional brackets

203

683

Units: mm

449

379

BLOCK DIAGRAM

AMP 4/5 AMP 5/5 AMP 1/5

Mic Input

Line Input/Output

Phone Jack

IC102

CN101-6

13131

HPF

IC101

CN102-6

CN101-4

CN102-4

Mic

VR101 VR104

Line

VR102

Master

LOW CUT P.AMP

IC104

Freq. response

compensation 51

IC107 IC108

IC105

LOW

HPF

VR103

LPF

IC106

HIGH

VR105

CN103-6

CN201-6

CN103-4

CN201-4

P.AMP

CN203-3(LF-), CN203-4(LF+)

SPEAKER

CN203-1(HF+), CN203-2(HF-)

SPEAKER

PANEL LAYOUT

Rear Panel

TONE CONTROL

LOW

LEVEL LEVEL LEVEL

HIGH

MS400

1 2 3

POWER switch

AC IN connector

LINE connectors

LINE LEVEL control

MIC connector

MIC control

MASTER LEVEL control

POWER indicator

TONE CONTROL

132

231

132

MS400

CIRCUIT BOARD LAYOUT

AMP

3/5

AMP

1/5

2/5

AMP

5/5

4/5

WIRING

MS400

Speakers

WF TW

AMP

5/5

1/5

CN201

CN103

CN203

CN202

H only

Coil

Transformer

CN102

CN101

AMP

4/5

YE BL

CN208

2/5

CN205

CN204

AMPAMP

P.SWAC.IN

3/5

MS400

DISASSEMBLY PROCEDURE

1. Amplifier assembly

1-1. Remove the sixteen (16) screws marked [180A]. The

amplifier assembly can then be removed. (Fig. 1)

2. Cabinet assembly and buffle assembly

2-1. Remo ve the nineteen (19) scre ws marked [170]. The

buffle assembly can then be removed from the capinet assembly. (Fig. 1)

3. Speakers (38cm, 25mm)

3-1. Remove the buffle assembly from the cabinet

assembly. (See Procedure 2.)

3-2. To remove the 38cm speaker, remove the four (4)

screws marked [180B] and the front grille. (Fig. 1)

3-3. Remove the eight (8) bolts marked [70]. The 38cm

speaker can then be removed. (Fig. 1)

3-4. To remove the 25mm speaker, remove the four (4)

screws marked [120]. Then remov e the speaker with the bracket. (Fig. 1)

3-5. Remove the two (2) screws mark ed [100]. The 25mm

speaker can then be removed from the brac ket. (Fig. 1)

[70]

[180A]

[170]

[180B]

[180A]

[70]: Hexagonal Bolt 5.0 X 35 MFZN2BL (V6389200) [120]: Bind Head Tapping Screw-P 5.0 X 30 MFZN2BL (V6405200) [170]: Bind Head Tapping Screw-P 5.0 X 50 MFZN2BL (V6084800) [180]: Bind Head Screw-Giza 4 X 16 MFZN2BL (V6396400)

[170]

[120]

38cm Speaker

Red Black

25mm Speaker

[100]

Red marking

Yellow

Blue

Fig.1

4. AMP Circuit Boards (1/5 to 5/5)

4-1. Remove the amplifier assembly. (See Procedure 1.) 4-2. Remove the screws and the knob from each circuit

board, which can then be removed. (Fig. 2)

PCB Name Ref No. Description Q'ty

AMP1/5 90 Bind Head Tapping Screw-B 3.0 X 12 MFZN2BL (VQ074600) 10

Circuit Board

100 Bind Head Screw SP 3.0 X 8 MFZN2Y (EG330290) 4

AMP2/5 80A Bonding Screw-B 4.0 X 12 MFZN2BL (V7242900) 2

Circuit Board

AMP3/5

Circuit Board

130 Bind Head Screw 4.0 X 8 MFZN2BL (VP156800) 1

110A Bonding Screw-B 3.0 X 8 MFZN2BL (VN413300) 2

AMP4/5 110B Bonding Screw-B 3.0 X 8 MFZN2BL (VN413300) 6

Circuit Board

Hexagonal Nut 1

AMP5/5 150 Knob MX-GREEN/D-GRAY (VU860200) 2

Circuit Board

160 Knob ORANGE/D-GRAY (VV625800) 2 170 Knob RED/D-GRAY (VU860400) 1 200 Button 3 X 25 MFZN2BL (V3289800) 4

MS400

5. Power transformer

5-1. Remove the amplifier assembly. (See Procedure 1.) 5-2. Remove the four (4) scre ws marked [80B]. The po wer

transformer can then be removed. (Fig. 2)

[150]

[80B]

Hexagonal nut

[80A]

[200]

[170] [160]

[110B]

[100]

1/5

AMP

[90] [90]

[120]

AMP

5/5

AMP

4/5

[110A]

AMP

2/5

[130]

3/5

[80]: Bonding Screw-B 4.0 X 12 MFZN2BL (V7242900)

Fig.2

MS400

6. Handle

6-1. Remove the cabinet assembly. (See Procedure 2.) 6-2. Remove the two (2) screws marked [70] and the tw o

(2) nuts marked [80]. The handle can then be removed. (Fig.3)

7. Heat sink

7-1. Remove the amplifier assembly. (See Procedure 1.) 7-2. Remove the AMP 1/5 circuit board. (See Step 4-2.) 7-3. Remove the three (3) screws marked [120]. The heat

sink can then be removed. (Fig.2)

[120]: Bonding Screw-B 4.0 X 8 MFZN2BL (VR779900)

IC BLOCK DIAGRAM

NJM2068L-D (XM356A00)

(IC101,103,104,105,106,107,108)

NJM4580L (XF195A00)

(IC102)

Operational Amplifier

[70]

[80]

Fig.3

1A2 3 4 5 6 7 8

IN V

OUT

AAA

IN BBB

OUT

VIN

+ 21 hidden pages

Yamaha MS-400 Service Manual

CONTENTS

SPECIFICATIONS

DIMENSIONS

BLOCK DIAGRAM

PANEL LAYOUT

Rear Panel

CIRCUIT BOARD LAYOUT

WIRING

DISASSEMBLY PROCEDURE

IC BLOCK DIAGRAM