AKG WMS-40 SERVICE MANUAL

WMS 40

Service Manual

Feb., 2007

Last modifications:

New part number pos. 15 page 6

Correction of part number's page 6

New part number pos.17 page 12

Part number for XL1, page 20

Designation of KR3 crystal corrected from 19115330 to 19115530

Page 22 connector: remark added

HT40: parts added

Page 20: CF1,3 part number corrected from 17001073 to 17201073

Crystals and ceramic filters for HT, PT and SR added

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AKG Acoustics GmbH, A Harman International Company, Lemböckgasse 21 - 25, A-1230 Wien Austria

Tel.: +(43 1) 86654 - 0; Fax.: +(43 1) 86654 - 1514; service@akg.com

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WMS 40

The complete WMS 40 system:

The actual frequency is not differentiated by item number!

WMS 40 HT/US – Set with US power supply: 7611X0001 WMS 40 HT/EU – Set with EU power supply: 7612X0001 WMS 40 HT/UK – Set with UK power supply: 7613X0001

WMS 40 PT/US – Set with US power supply: 7611X0002 WMS 40 PT/EU – Set with US power supply: 7612X0002 WMS 40 PT/UK – Set with US power supply: 7613X0002

WMS 40 PT/US/Aerobic – Set with C444 and US power supply: 7611X0003 WMS 40 PT/EU/Aerobic – Set with C444 and EU power supply: 7612X0003

HT 40, handheld transmitter only: 7600X0001 PT 40, bodypack transmitter only: 7600X0002

SR40/US, receiver only with US power supply: 7601X0003 SR40/EU, receiver only with EU power supply: 7602X0003 SR40/UK, receiver only with UK power supply: 7603X0003

General remarks

This manual contains technical information on the system functions and design. Exploded views and lists of all available mechanic parts and electronic assemblies are added. Further a list of electronic components for one specific frequency for both handheld and bodypack transmitters and receiver is added for better technical understanding and trouble shooting. However we do not stock or sell electronic components contained in those electronic components lists. When ordering frequency depending boards please state part number

plus required frequency.

All measurement values are nominal if not otherwise specified. All data subject to change without prior notice . All rights reserved. The contents of this manual shall be used for service purposes only. Any use of the information given herewith by third parties without permission of the copyright owner is strictly forbidden!

Contacts:

e-mail: service@akg.com

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WMS 40

Short description Transmitter HT40:

Audio part:

The dynamic unit (D880) is connected via L1-L2-C6-C7 (RF-filter), to the MICAMP The MICAMP is built as an amplifier, which is a part of the NE575- integrated circuit and has a gain of 8.8dB. It also forms the LOCUT

ressor.

COMP

filter at 30 Hz. Then the signal is fed to the

Here the dynamic of the amplitude is reduced to its half value, expressed in dB. This compressor is built with the integrated circuit NE575 from Signetics. In the feedback loop of the amplifier (Pin 12 and 14) there is the variable gain cell inserted. The variable gain cell is controlled by the rectified output voltage of the amplifier. C60 smoothes the rectified signal an controls the variable gain cell. C60 defines the so called time constant of the compressor. This feedback loop leads in an compression of the input signal. R7-R8-C10 build the DC path in the feedback loop. The second amplifier is used to build the PREEM

phasis circuit, which boosts the higher frequencies with an time constant of 50usec and a fixed gain of 7.9dB at the lower frequencies. The DEV

iation ADjustment is realized with the potentiometer R16. Here at an input level of 100mV/1kHz the deviation is adjusted to 15kHz, which is the nominal modulation. Also at MUTE-position of the main switch, the signal is here shorted. Q2 with the additional parts form the HICUT

filter at app. 25 kHz/3rd order.

Via C29-R28-C30-R30 the signal modulates the CCO.

RF part:

The UHF Signal is generated by a crystal controlled oscillator CCO stages (AMP1 The third harmonic of the CCO is filtered by BPF1 filtered by BPF2 filter BPF3

, AMP2, AMP3, AMP4).

, after 3 doubler stages Ftransmit/2 is

. After the output amplifier AMP5 the signal is filtered by LPF and a ceramic

and multiplier amplifier

SETCode Transmitter Frequency Cryst all Frequency Color

US54 710,400MHz 14,800MHz reddish brown

US58 734,600MHz 15,304MHz purple

EU62 802,525MHz 16,719MHz warm red

EU63 812,800MHz 16,933MHz yellow

UK69A 854,900MHz 17,810MHz violet

UK69B 858,200MHz 17,879MHz green

ISM1 863,100MHz 17,981MHz melon yellow

ISM2 864,375MHz 18,008MHz cool gray

SP1 848,750 MHz 17,6822 MHz skyblue

SP2 851,750 MHz 17,7447 MHz yellow green

KR3 745,650 MHz 15,5344 MHz mintgreen

KR4 750,900 MHz 15,6438 MHz dark grey

Power supply: The internal voltage of 3.9V is generated from 2 AA size batteries with a DC/DC

converter.

stage.

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ANT

LPF

Ftransmit

AMP3 AMP4AMP2MICAMP BPF1 BPF2 BPF3

WMS 40

HT40-block schematics

UHF-frequency rangeAF-frequency 40Hz ... 20KHz

doubler doubler doubler doubler

Ftransmit/16 Ftransmit/2 Ftransmit

XT2

3.9V

CCO AMP1 AMP5 LPF

HICUTLOCUT

COMP PREEMWIRE

OFF

23KHz

Order3

MUTE

Order1

3.1KH z

Ftransmit/48

DC/DC

UBat t

OFF

MUTE

SWITCH

LOWBATT

BATTERY

Order 2

40Hz

2 wires

MIC

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13 10 11 15 14 18 16 19

Attention: Before reassembly twist stranded wires leading to capsule in counterdirection to the way of screwing in the threaded sleeve. Otherwise the wires will break.

Achtung: Vor dem Zusammenbau die Litzen zur Kapsel im Gegensinn zur Schraubrichtung der Gewindehülse verdrillen, da sonst die Anschlüsse abreissen!

WMS 40

Part nbr. :31404010

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WMS 40

Printed circuit main board, complete, tested 80004012 1 Printed circuit dc/dc board, complete, tested 80004013 2 ON/MUTE/OFF switch 92100400 3 Crystal 14.8003MHz (For US54, 710.400MHz) reddish brown Crystal 14.8128MHz (For US54B, 711,000MHz) skyblue 19114811 4 Crystal 15.3045MHz (For US58, 734.600MHz) purple 19115301 4 Crystal 15.354MHz (For US58B, 736.975MHz) yellowgreen 19115350 4 Crystal 15.602 MHz (For US60A, 748.875MHz) green 19115600 4 Crystal 15.6576MHz (For US60B, 751.550MHz) dark purple 19115650 4 Crystal 16.7196MHz (For EU62, 802.525MHz) warm red 19116710 4 Crystal 16.7732MHz (For EU62B, 805.100MHz) pink 19116772 4 Crystal 16.9336MHz (For EU63, 812.800MHz) yellow 19116930 4 Crystal 16.9399MHz (For EU63B, 813.100MHz) light red 19116931 4 Crystal 17.8107MHz (For UK69A, 854.900MHz) violetblue 19117810 4 Crystal 17.8795MHz (For UK69B, 858.200MHz) green 19117871 4 Crystal 17.9815MHz (For ISM1, 863.100MHz) melon yellow 19117980 4 Crystal 18.0081MHz (For ISM2, 864.375MHz) cool gray 19118000 4 Crystal 18.0180MHz (For ISM3, 864.850MHz) violet 19118011 4 Crystal 15.5344MHz (For KR3, 745.650MHz) mint green 19115530 4 Crystal 15.6438MHz (For KR4, 750.900MHz) dark gray 19115640 4 Crystal 17.6822MHz (For SP1, 848.750MHz) 19117680 4 Crystal 17.7447MHz (For SP2, 851.750MHz) 19117740 4 Crystal 16.846MHz (For JP1, 808.625MHz) greenbrown 19116840 4 Crystal 16.857MHz (For JP2, 809.125MHz) light blue 19116850 4 Ceramic Filter 710.151MHz (For US54) 19307100 20 Ceramic Filter 734.151MHz (For US58) 19307340 20 Ceramic Filter 747.141MHz (For KR3) 19374710 20 Ceramic Filter 750.141MHz (For KR4) 19307500 20 Ceramic Filter 802.151MHz (For EU62) 19308020 20 Ceramic Filter 812.151MHz (For EU63) 19308120 20 Ceramic Filter 854.151MHz (For UK69A) 19308540 20 Ceramic Filter 858.151MHz (For UK69B) 19308580 20 Ceramic Filter 864.152MHz (For ISM1) 19308640 20 Ceramic Filter 864.152MHz (For ISM2) 19308640 20 Ceramic filters for further frequencies on request 20 Battery compartment 24200010 5 Battery contact (helical spring) 36304010 6 Battery contact (plate) 36205150 7 Housing tube, printed 27004010 8 Antenna cover, black 21504010 9 Antenna cover, orange 21504013 9 Antenna cover, yellow 21504014 9 Antenna cover, red 21504012 9 Antenna cover, brown 21504011 9 Antenna cover, pink 21504017 9 Antenna cover, green 21504015 9 Antenna cover, violet 21504016 9 Antenna cover, grey 21504018 9 ON/MUTE/OFF label with LED lens 22004010 10 ON/MUTE/OFF slider 25204010 11 Frame for ON/MUTE/OFF slider 22204010 12 Battery door 20104040 13 Capsule 2610Z0034 14 Top grill (39004010) new 9999N07180 15 Housing screw 33002060 16 Rubber plate 65045140 17 Ring 36104010 18 Cover 30818090 19 Stand adapter 23200010 --

Description Part number Item

19114801 4

Short description Transmitter PT40:

Audio part:

The input signal is connected at Pin2 via L13L14C44C72 (RFfilter), to the MICAMP (with Pin1 = ground). The supply voltage of 3.9V for the microphones is connected via R68 at pin 3 of the connector . For microphone application Pin2 and Pin3 has to be shorten in the connector of the microphone. The MICAMP is built as an amplifier, which is a part of the NE575 integrated circuit and has a variable gain of 0dB to 21dB. It also forms the LOCUT filter at 30 Hz and the MIC/LINE switch is situated here, which reduces the input signal by app. 14dB at line position. Then the signal is fed to the COMP

ressor. Here the dynamic of the amplitude is reduced to its half value, expressed in dB. This compressor is built with the integrated circuit NE575 from Signetics. In the feedback loop of the amplifier (Pin 12 and 14) is the variable gain cell inserted. The variable gain cell is controlled by the rectified output voltage of the

stage

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WMS 40

amplifier. C18 smoothes the rectified signal an controls the variable gain cell and is the so called timeconstant of the compressor. This feedback loop leads in an compression of the input signal. R45R46C24 build the dcpath in the feedback loop. The second amplifier is used to build the preemphasis circuit, which boosts the higher frequencies with an time constant of 50usec and a fixed gain of 7.9dB for the lower frequencies. The deviationadjustment is realized with the potentiometer VR3. Here at an inputlevel of 300mV at 1kHz (and the inputgain set to 0dB=minimumgain) the deviation is adjusted to 15kHz, which is the nominal modulation. Also at MUTEposition of the main switch, the signal is here shorted. Q7with the additional parts form the HICUTfilter at app. 25 kHz / 3. order. Via C25R69C26R17 the signal modulates the CCO.

RF part:

The UHF Signal is generated by a crystal controlled oscillator CCO stages (AMP1 The third harmonic of the CCO is filtered by BPF1 filtered by BPF2 filter BPF3

, AMP2, AMP3, AMP4).

, after 3 doubler stages Ftransmit/2 is

. After the output amplifier AMP5 the signal is filtered by LPF and a ceramic

and multiplier amplifier

Power supply:

The internal voltage of 3.9V is generated from 2 AA size batteries with a DC/DC

converter.

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WMS 40

ANT

LPF

Ftransmit

AMP3 AMP4AMP2

UHF-frequency rangeAF-frequency 40Hz ... 20KHz

PT40-block schematics

doubler doubler doubler do ubler

BPF1 BPF2 BPF3

CCO AMP1 AMP5 LPF

HICUT

COMP PREEM

40Hz

LOCUT

Ftransmit/16 Ftransmit/2 Ftransmit

XT2

3.9V

Ftransmit/48

OFF

23KHz

Order3

MUTE

Order1

3.1KHz

MICAMP

Order 2

DC/DC

UBatt

OFF

MUTE

SWITCH

-22...0d B

LOWBATT

BATTERY

GAINPOT

ATT

CON

MIC

0dB -14dB

MIC/LINE

3 Pins

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