ALLEN & HEATH

WARNING – HIGH VOLTAGES

Power Supply Unit (PSU) work should only be carried out by qualified personnel.

We recommend that you use an approved Allen & Heath service centre for all power supply work.

Please contact your local Allen & Heath distributor for more details. http://www.allen-heath.com/

MixWizard Series

WZ20S

Stereo Audio Mixing Console

SERVICE MANUAL

Publication No: AP3638

CONTENTS

INTRODUCTION, SERVICE AND TECHNICAL SUPPORT.................3

FLIGHTCASING THE CONSOLE & DIMENSIONS .............................4

SPECIFICATIONS & CONNECTIONS.................................................5

ORDERING A MIXWIZARD WZ20S UNIT, OPTIONS & MANUALS ....6

ORDERING SPARE ASSEMBLIES......................................................6

ORDERING SPARE PARTS.................................................................7-8

MONO INPUT BOARD COMPONENT IDENT.....................................AG3379

MONO INPUT BOARD CIRCUIT DIAGRAM........................................C3379

STEREO INPUT BOARD COMPONENT IDENT .................................AG3408

STEREO INPUT BOARD CIRCUIT DIAGRAM ....................................C3408

LEFT BOARD COMPONENT IDENT ...................................................AG3627

LEFT BOARD CIRCUIT DIAGRAM (P

AGE

1

OF

2)................................C3627

LEFT BOARD CIRCUIT DIAGRAM (P

AGE

2

OF

2) ................................C3627

RIGHT BOARD COMPONENT IDENT.................................................AG3626

RIGHT BOARD CONNECTOR CIRCUIT DIAGRAM (P AGE 1 OF 2)......C3626

RIGHT BOARD CONNECTOR CIRCUIT DIAGRAM (P AGE 2 OF 2)......C3626

CONNECTOR BOARD COMPONENT IDENT.....................................AG3632

CONNECTOR BOARD CIRCUIT DIAGRAM (P

AGE

1

OF

3)..................C3632

CONNECTOR BOARD CIRCUIT DIAGRAM (P

AGE

2

OF

3)..................C3632

CONNECTOR BOARD CIRCUIT DIAGRAM (P AGE 3 OF 3)..................C3632

Warning to the Service Engineer

Allen & Heath warns that any unauthorised changes or modifications to the WZ20S unit may invalidate the legal compliance of the unit and could void the user’s authority to operate the equipment.

WZ20S Service Manual AP3638 Issue 2. Copyright © 2005 Allen & Heath. All rights reserved

M

ANUFACTURED

I

N

E

NGLAND BY

:

ALLEN & HEATH

Kernick Industrial Estate

Penryn, Cornwall, TR10 9LU. UK http://www.allen-heath.com

A

LLEN

& H

EATH

A

GENT

:

2 WZ20S S ERVICE M ANUAL

Introduction

The information presented in this manual is intended for competent technical personnel to carry out service and product support for the MixWizard WZ20S console. We assume that the reader is familiar with the related electronic theory and audio terminology, and is able to carry out basic servicing, faultfinding and repair of audio equipment of this type. Service personnel should also be familiar with audio systems, mains earthing and power requirements, as well as handling precautions.

For information on the configuration, operation and application of the MixWizard WZ20S please refer to the User Guide.

Whilst we believe the information in this manual to be reliable we do not assume responsibility for inaccuracies. We also reserve the right to make changes in the interest of further product development.

Service and Technical Support

Under normal operating conditions the MixWizard WZ20S does not require user maintenance or internal calibration. Any service work required should be carried out by qualified technical personnel only.

We are able to offer further product support through our worldwide distribution network. To help us provide an efficient service please quote the console serial number, the date and place of purchase in any communication regarding this product.

SAFETY WARNING!

Mains electricity is dangerous and can kill. Mains voltage is present within the unit.

Do not remove the cover with mains electricity connected. To ensure your safety, mains earth is connected to the chassis through the power lead. Do not remove this mains earth connection.

To avoid the risk of fire, replace the mains fuse with the correct value and type as indicated on the rear panel.

Before switching on your console, check that the fuse is of the correct rating and type. This is clearly marked on the rear panel. Do not replace the fuse with any other type, as this could become a safety hazard and will void the warranty.

General Precautions

Your WZ20S is ruggedly constructed to give many years of reliable operation. However, you will extend the life of the console and preserve its cosmetics by applying these simple common sense precautions.

• Avoid storing or using the mixing console in conditions of excessive head or cold, or in positions where it is likely to be subject to vibration, dust dirt or moisture.

• Do not use any liquids to clean the control surface of the console, a soft dry brush or dry lint-free cloth is ideal.

• Use only water or ethyl alcohol to clean the trim and scribble strips. Other solvents may cause damage to paint or plastic parts.

• The faders, switches and potentiometers are lubricated for life. The use of electrical lubricants on these parts is not recommended.

• Avoid using the console close to strong sources of electromagnetism radiation (e.g. video monitors, high power electric cabling): this may cause degradation of the audio quality due to induced voltages in connecting leads and chassis.

WZ20S S ERVICE M ANUAL 3

Flightcasing the Console

If the console is to be regularly moved we recommend that it is installed in a foam-lined flightcase. At all times avoid applying excessive force to any knobs, switches or connectors.

Dimensions for flightcasing the console are shown below:

Dimensions

Desktop ........................ 483mm (19”)................. 192mm (7.6”).................530mm (20.9”)

Rack mounted .............. 483mm (19”)................. 444mm (17.5”) 10U .......135mm (5.3”)

Packed.......................... 590mm (23.2”).............. 260mm (10.2”)...............610mm (24”)

Weight........................... 10kg (22lbs).................. 13kg (29lbs)

4 WZ20S S ERVICE M ANUAL

Specifications

0dBu = 0.775 Volts rms

0dBV = 1 Volt rms

+4dBu = 1.23V rms

-10dBV = 316mV rms

INTERNAL HEADROOM:

....................................... Channels ........................ +21dB

....................................... Mix to output ................... +23dB

MAXIMUM OUTPUT LEVEL:

XLR ..........................................+26dBu into >2k ohm load

TRS jack ...................................+21dBu into >2k ohm load

PEAK INDICATORS:..............Turn on 5dB before clipping

METERS:

........... MIX 1,2 / MONITOR Peak reading 12 led 3 colour

FREQUENCY RESPONSE:

......................................................20Hz to 50kHz +0/-1dB

DISTORTION: THD+noise @ +14dBu 1kHz

............................................................................ < 0.006%

CROSSTALK: Channel shutoff measured at 1kHz

................................................................................ < 90dB

Connections

NOISE: Measured rms 22Hz to 22kHz

MIC EIN: referred to 150 ohm source

................................................................................-128dB

RESIDUAL OUTPUT NOISE:

........................................... XLR -90dBu (-94dB S/N)

........................................... TRS jack -94dBu (-94dB S/N)

MIX NOISE, CH ROUTED:

........................................... XLR -86dBu (-90dB S/N)

........................................... TRS jack -90dBu (-90dB S/N)

POWER SUPPLY: 100 to 240V AC @ 50/60Hz

Internal switch mode power unit with auto sensing mains input.

Power Consumption ............................................35W max

Mains fuse rating 100-240VAC .................T500mA 20mm

INPUTS:

Mic in...................... XLR.....................pin 2 hot, 3 cold, balanced ..............................2k Ohm......... variable –60 to -20dBu

Line in..................... TRS jack .............tip hot, ring cold, balanced ..............................>10k Ohm..... variable –30 to +10dBu

Stereo Ch in A........ RCA PHONO ......unbalanced......................................................>10k Ohm..... variable –20 to +10dBu

Stereo Ch in B........ TRS jack .............tip hot, ring cold balanced ...............................>10k Ohm..... variable –20 to +10dBu

EXT in 1-2 .............. TRS jack .............tip hot, ring cold balanced ...............................>10k Ohm..... variable –10dBV (+4dBu option)

OUTPUTS:

Direct out 1-4.......... TRS jack .............tip hot, ring cold, impedance balanced..........<75 Ohm ........ 0dBu

Mix out 1-2 ............. XLR.....................pin 2 hot, 3 cold, balanced ............................<75 Ohm ........ +4dBu

Mix out 2................. TRS jack .............tip hot, ring cold, impedance balanced..........<75 Ohm ........ -2dBu

Mono out ................ XLR.....................pin 2 hot, 3 cold, balanced ............................<75 Ohm ........ +4dBu

Aux out 1-6............. TRS jack .............tip hot, ring cold, impedance balanced..........<75 Ohm ........ -2dBu

Phones out 1, 2 ...... TRS jack .............tip left, ring right.............................................for stereo headphones 75 to 600 Ohms

INSERTS:

Mono Channel:

Send....................... TRS jack .............tip send, ring return, unbalanced...................<75 Ohm ........ 0dBu

Return .................... TRS jack .............tip send, ring return, unbalanced...................>3k Ohm

Mix out 1-2:

Send....................... TRS jack .............tip send, ring return, unbalanced...................<75 Ohm ........ -2dBu

Return .................... TRS jack .............tip send, ring return, unbalanced...................>7k Ohm

WZ20S S ERVICE M ANUAL 5

ORDERING A CONSOLE

To order a new

MixWizard

console please specify the model number and AC mains voltage.

MODEL DESCRIPTION

MIXWIZARD WZ20S 4 Mono + 8 Stereo Input Channels WZ20S/volts

ORDERING AN OPTION

To order an option please specify the model number required.

RIAA OPTION

FADER START

FADER START

WZ20S RIAA DUAL INPUT OPTION W21442/20S-RIAA

WZ20S MONO FADER START OPTION 002-496

WZ20S 4M8S FADER START OPTION 002-501

MANUALS AND SUPPORT DOCUMENTATION

DESCRIPTION

MIXWIZARD WZ20S User Guide

MIXWIZARD WZ20S Service Manual

AP3634

AP3638

MIXWIZARD WZ20S Flyer AP3637

SERVICE TOOLS

The tools required to service the MixWizard WZ20S are standard to an electronics service workshop and are easily obtainable. The following items are necessary for disassembly and service access:

1-point Crosshead screwdriver (M3, M4, 4AB) AT0004

11mm AF Nutdriver (potentiometer, headphone socket and jack nuts)

ORDERING AN ASSEMBLY

The following assemblies for the MixWizard WZ20S are supplied fully tested. Please quote the description and order code for the part required.

Printed circuit board (PCB) assemblies:

Mono Input PCB assembly

Left PCB assembly

Right PCB assembly

Stereo PCB assembly

Connector PCB assembly including Power Supply

IDC connector harnesses:

WZ20S 16 way Main harness

WZ12/16/20S/464 34 way Master harness

002-483

002-484

002-485

002-487

002-486

AL3669

AL3518

6 WZ20S S ERVICE M ANUAL

ORDERING A SPARES KIT

It is recommended that the spares kit order code 002-491 is held and maintained by the service agent to enable in-field service repairs to the WZ20S independent of the ALLEN & HEATH factory.

Commonly available items such as resistors, capacitors, tools and soldering equipment are not included. The contents of the kit are listed below and are supplied in a cabinet of drawers. Individual spare parts may be ordered. Please quote the description and order code for the part required.

QTY DESCRIPTION

Fixings:

Screw M3 x 6mm TT Pan Pozi Black

Screw M3 x 8mm Pan Pozi Black

Screw M3 x 10mm Pan Pozi Black

Nylock Nut M3

Screw M3 x 4mm Pan Pozi Black

Washer M3 Shakeproof

Screw 4AB x ¼ Pan Pozi Plated

Screw 4 x 5/16” Poly Pan Pozi Black

Screw M3 x 6mm TT CSK Pozi Black

ORDER CODE

AB0071

AB0073

AB0076

AB0102

AB0233

AB0244

AB0252

AB2810

AB2929

Knobs and caps:

Knob Red & Grey 11mm D

Knob Blue & Grey 11mm D

Knob Light Blue & Grey 11mm D

Knob Green & Grey 11mm D

Knob Dark Grey & Grey 11mm D

Knob Yellow & Grey 11mm D

Knob Brown & Grey 11m D

Button 5.5mm Square Grey

Button 10x5mm Rectangular Grey

Button Round Black

Button 5.5mm Square White

Button 5.5mm Square Red

Button 10 x 5mm Rectangular White

Switch Cap Tall

Fader Knob 11mm White+Black Line

Fader Knob 11mm Yellow+Black Line

Fader Knob 11mm Blue+Black Line

Faders, Potentiometers, Switches and connectors:

Pot 20KK (203K 11mm wide)

Pot 20KB centre click (203B 11mm wide)

Pot 200KC x 2 (204C 1mm wide)

Pot 20KB x 2 centre click (14mm wide)

Pot 20KK x 2 (203K 14mm wide)

Pot 10KAC x2 (103AC 14mm wide)

Pot 5K (502RD 11mm wide)

Fader 10KD 100mm

Fader 10KD x 2 100mm

Switch 2PCO Latching 90°

Jack Socket Headphone

AI8003

AI8004

AI8005

AI8006

AI8007

AI8008

AI8111

AI8117

AI8118

AL0162

AL0328

XLR 3 Pin Female Vertical PCB Mount

XLR 3 Pin Male Vertical PCB Mount

AL2410

AL2411

Phono Socket 24mm Dual Vertical PCB Mount AL3240

Jack Socket ¼” Stereo Unswitched AL3407

Jack Socket ¼” Stereo Switched

Switch 2PCO Latching Vertical

Switch 2PCO Latching 90Deg

Pot Nut 9mm

AL3410

AL8057

AL8065

AB8050

AJ2074

AJ2075

AJ2076

AJ2077

AJ2078

AJ2079

AJ2080

AJ2864

AJ2865

AJ2887

AJ2960

AJ2961

AJ2962

AJ8071

AJ8078

AJ8080

AJ8081

5

10

5

3

10

10

10

10

10

10

5

10

10

5

5

5

10

10

10

10

10

10

5

1

10

5

10

10

10

5

10

10

5

5

10

5

1

3

3

5

5

5

3

5

20

WZ20S S ERVICE M ANUAL 7

LEDs and Semiconductors:

Transistor BC549 NPN

Transistor BC638 PNP TO92H

IC TL072 Dual Op-Amp

Transistor BC637 NPN TO92H

IC LM339N Quad Comparator

Transistor J111N FET T092B

LED 3mm T1 Red

IC CMOS 4053B

IC Op-Amp NE5532N

Transistor 2N4403 PNP

IC SSM2142P Bal Out Driver

LED Bar Rectangular 12 Way

Transistor BC556B PNP

LED Rect Green 5X2MM Flat Top

LED Rect Red 5X2MM Flat Top

IC TL072 Op-Amp SIL

Transistor MPSA92 PNP

POWER SUPPLY:

Insulation Guard

Mains Lead IEC-2 Pin (Europe)

Mains Lead IEC-3 Pin (UK)

Mains Lead IEC-3 Pin C33 (USA)

Fuseholder 20mm PCB Mount

IC Opto-Isolator 4N35

Diode Zener 47V 500mW

Transistor TIP122

Diode BYV27-400 2A

Diode BYV26E 1A 1000V

Diode P6KE200A

Transistor Mosfet STP4NA80FI

IC SMPS UC3842AN

IC TL431 Voltage Reference

Bridge Rectifier 2KBP04M

Inductor 4.7uH 600mA

Transformer Wizard Switch Mode

Miscellaneous:

MixWizard Box + Fittings

Flex cable 39 way 200mm

Flex Socket 12 Way 90Deg

Flex Socket 12 Way Straight

Flex Socket 8 Way 90Deg

Flex Socket 39 Way Straight

AA3509

AH0205

AH0206

AH0323

AL3178

AE0266

AE2999

AE3215

AE3469

AE3470

AE3471

AE3472

AE3473

AE3475

AE3477

AM3467

AM3476

AE0020

AE0037

AE0046

AE0068

AE0071

AE0083

AE0086

AE0117

AE0221

AE0273

AE0302

AE2701

AE3001

AE3501

AE3502

AE8070

AE8119

AP2915

AH2900

AL2226

AL2227

AL2901

AL2902

5

5

3

3

-

1

1

1

1

-

-

-

3

1

2

2

1

-

-

-

-

2

-

5

2

5

1

5

5

5

10

3

2

5

10

5

5

5

3

2

8 WZ20S S ERVICE M ANUAL