Welch Allyn AudioScope 3 User manual

®

Service Manual

AudioScope™/ AudioScope 3™

Screening Audiometers

Single Hearing Level Models: 23020, 23000, 23040

Three Hearing Level Model 23300

Charging Stand 71123

Charging Transformers: Australia - 71036, Europe - 71032, Japan -71030,

United Kingdom 71034, United States - 71040

Welch Allyn, Inc.

4341 State Street Road

P.O. Box 220

Skaneateles Falls, NY 13153-0220

PN: 230260 Rev. B Copyright 2004

__________________________________________________________________________

Revision History

ECN#/

ECO#

5-32904

5-32904

5-32904

5-32904

5-32904

1001574 B 6/17/04 Soldering BSW

Revision

A

A

A

A

A

Date Section

5/31/96

5/31/96

5/31/96

5/31/96

5/31/96

1

2

3

4

5

Title

General Info.

Service

Troubleshooting

Disassembly/Rep

air

Drawings/Specs.

Author

RJS

RJS

RJS

RJS

RJS

Description

Added Soldering

Intro of

Document

Intro of

Document

Intro of

Document

Intro of

Document

Intro of

Document

Temperatures

Drawings and/or illustrations and/or part numbers in

this document are for reference only. For the most

current revision call the Welch Allyn Customer Service

phone number listed in Section 1.

- 3 -

______________________________________________________________________________________

Table of Contents

Sub Sect Pg.

Cover Page 1
Revision Page 3
Table of Contents 4-5

SECTION 1: General Information

To Service Personnel 1.1 7
Limited Warranty 1.2 8
Introduction to AudioScopes 1.3 9-11
Figure 1.3 AudioScope Handle Controls 1.3 11
Basic System Description (Fig.1.4a Basic System) 1.4a 12
Basic System Description (charging stand) 1.4b 12
Use of the AudioScope (Screening) 1.5 13-14
Operating Program 1-Lev (Fig 1.6 Block Diagram) 1.6 15-17
Operating Program 3-Lev (s/n<=969999) ASIC 1.7a 18-20
Operating Program 3-Lev (s/n>=970000)nonASIC 1.7b 21-22
Technical Functional Specifications (All Models) 1.8 23

SECTION 2: Service

Intent of Service Manual 2.1 25
Repair Parts for AudioScope 2.2 26
Lists of Tools/Fixtures/Documents for Service 2.3a 27-28
Fig. 2.3b Tools/Fixtures Setup for Calibration for
AudioScope and AudioScope 3 s/n<=969999 2.3b 29

Fig. 2.3c Tools/Fixtures Setup for Calibration for

AudioScope 3 s/n>=970000 2.3c 30
Training 2.4 31

Calibration (Single Level 23020,23000,23040) 2.5 32-33

Figure 2.5.4 Sound Tube Placement/Adjustment 2.5 32
Calibration (Multi Level 23300) s/n <=969999 2.6 34-35
Calibration (Multi Level 23300) s/n >=970000 2.7 36-37

SECTION 3: Troubleshooting 23300

Troubleshooting AudioScope 3 s/n <=969999 3.1 39
Troubleshooting AudioScope 3 s/n >=970000 3.2 40

SECTION 4: Disassembly and Repair, AudioScope 3

Handle 4.1 43-45
Charging stand 4.2 46

- 4 -

____________________________________________________________________________________

Table of Contents

conti nu e d

SECTION 5: Drawings/ Test Specifications

Manilla Pockets contain 17" x 22" drawings. 5.1 49

Drawing# Description Original Size/#sheets

A02030 Repair Calibration Spec. for AudioScope II B/1 of 1
A00277 Audiometer Handle Test Specifications D/1 of 1
A00984 P.C.B. Test Spec AudioScope II D/1 of 1
A00273 Electronics Module Test Specification D/1 of 2
A00273 Electronics Module Test Specification D/2 of 2
A00985 Audio Module III Test Spec D/1 of 1
A01825 AudioScope III Sound Equipment Calibration

and Setup C/1 of 1
A00942 Charging Stand Electrical Test Spec. A/1 of 1
230230 Audio II Schematic (PCB for ASIC version) D/1 of 1
230215 PC Board Ass'y (for ASIC version D/1 of 1
236630 PCB Schematic (for Microcontroller version) B

Parts catalog pages

230137-3 Nos.23000, 23020, 23040 AudioScope A/1 of 1
230237-1 No. 23300 AudioScope II and 3 A/1 of 1
711408-2 No. 71123 Charging Stand A/1 of 1

- 5 -

Section 1:

General Information

____________________________________________________________________________________

1.1 To Service Personnel

Read and understand the AudioScope operating instructions manual pn. 230231-

2. The information in this Service Manual is subject to change without notice
and should not be construed as a commitment by Welch Allyn. Welch Allyn
assumes no responsibility for any errors that may appear in this manual.

Who to contact:

If the product and/or its operation varies significantly from any description
therein, please contact:
Welch Allyn Medical Products Division
Product Service Department,
4341 State Street Road, Skaneateles Falls, NY, 13153-0220, U.S.A.
Phone [phone], or [phone].
Fax [phone]

This product has been designed to provide a high degree of safety and
reliability. However, we cannot guarantee against the deterioration of
components due to aging and normal wear.

All service and repairs must be done by authorized Welch Allyn personnel or
agents, using approved Welch Allyn replacement parts and approved process
materials. Failure to do so will invalidate the product warranty. Please refer
to the product warranty for specific coverage.

USING ADHESIVES: ALWAYS WEAR SAFETY GLASSES AND PROVIDE ADEQUATE
VENTILATION WHEN USING CA ADHESIVES, CA ACCELERATORS, AND RTV ADHESIVE
SEALANTS. READ AND OBEY WARNINGS, CAUTIONS, INSTRUCTIONS, AND
RECOMMENDATIONS PRINTED ON CONTAINER AND CORRESPONDING MSDS SHEETS

CCAAUUTTIIOONN:: PPRRIIOORR TTOO DDOOIINNGG RREEPPAAIIRR WWOORRKK,, UUNNPPLLUUGG PPOOWWEERR CCOORRDD OONN CCHHAARRGGEERR TTOO
EELLIIMMIINNAATTEE SSHHOOCCKK HHAAZZAARRDD.. UUSSEE GGRROOUUNNDDIINNGG MMAATT AANNDD GGRROOUUNNDDIINNGG SSTTRRAAPP TTOO
RREEDDUUCCEE CCHHAANNCCEESS OOFF DDAAMMAAGGEE TTOO AASSIICC IINN HHAANNDDLLEE.

.

- 7 -

______________________________________________________________________

1.2 Limited Warranty

Welch Allyn warrants the AudioScope, when new, to be free of defects in
material and workmanship and to perform in accordance with the
manufacturer's specifications for a period of one year from the date of
purchase from Welch Allyn or its authorized distributors or agents.

Welch Allyn will either repair, replace or recalibrate any components (except
lamps) found to be defective or at variance from the manufacturer's
specifications within this time at no cost to the customer, except for
transportation expenses. For rechargeable batteries, warranty is extended to
two years. It shall be the purchaser's responsibility to return the instrument
directly to Welch Allyn or to an authorized distributor, agent or service
representative.

This warranty does not include breakage or failure due to tampering, misuse,
neglect, accidents, modification or shipping. This warranty is also void if the
instrument is not used in accordance with the manufacturer's recommendations
or if repaired by other than a Welch Allyn or authorized agent. This warranty
can be extended to a three-year period provided the instrument is returned for
recalibration annually. Submission of instrument registration card is required.
Purchase date determines warranty and recalibration requirements. No other
express warranty is given.

To receive service assistance or to ask questions regarding this warranty,
please call or write:

Welch Allyn Product Service Dept.
Welch Allyn, Inc.
Medical Products Division

4341 State Street Road
Skaneateles Falls, New York 13153 USA
1 [phone] or [phone]

Note: The U.S. Occupational Safety and Health Administration (OSHA) recommends that audiometers
be calibrated annually. Arrangements for calibration can be made by returning the instrument
registration card. In addition a daily biological check may be performed. This is accomplished by a
person with known normal hearing who listens to the tones for intensity and quality. There is a
moderate fee for recalibration. *Re-printed from PN230108, Instrument Registration Card

- 8 -

___________________________________________________________________

1.3 Introduction to AudioScopes

The Welch Allyn AudioScope (audiometer) enables the practitioner to perform a
fast, painless and objective test for early hearing loss. The AudioScope3 starts
with a Practice Tone (PT) of 1,000 Hz at a dB HL dependent upon the selected
Screening dB HL.(Refer to Page 5 of Operating Instructions). After the Practice
Tone (PT), the AudioScope3 provides screening at all four speech frequencies:
1,000 Hz, 2,000 Hz, 4,000 Hz, and 500 Hz. This test can be performed at one
of three hearing levels: 20 dB, 25 dB, or 40 dB. Selection of the hearing level is
dependent on the age of the patient. Note: there is no PT with single level
AudioScopes. If a hearing problem is suspected, the patient is referred to a
specialist for diagnosis.
The AudioScope contains a 3.5-volt halogen lamp and otoscope lens for viewing
the tympanic membrane and the ear canal prior to and during hearing
screening.

There are two types of Welch Allyn AudioScopes in use today:

• The first type is the single hearing level instrument of which there are three

models. Although they are obsolete, they can still be calibrated if they are
functioning according to specifications. Service parts are not available.

AudioScope pn 23020 - 20 dB (no PT)
AudioScope pn 23000 - 25 dB (no PT)
AudioScope pn 23040 - 40 dB (no PT)

• The second type is the three hearing level (MultiLevel) AudioScope3. (Also

known as AudioScope II) There are two versions of this second type.

AudioScope3 pn 23300 - 20, 25, 40 dB (1000 Hz PT)

The original version of the AudioScope 3 (three hearing level) up to and
including serial number 969999 utilizes an ASIC module. This instrument is
calibrated by adjusting miniature potentiometers on the printed circuit board.

Although the main board/ASIC is being phased out at the time of this
writing, they can still be calibrated if they are functioning according to
specifications. Some parts are available. (See Repair Parts, Section 2.2)

NEW VERSION:

A new version (starting in 1996 with serial number 967000) differs from the

first AudioScope3 in that a Microcontroller is used instead of the ASIC.

Performance specifications of the new AudioScope 3 are identical to the earlier

AudioScope 3, and the part number remains the same. Since this version

utilizes a Microcontroller with digitally adjusted pots and not mechanical

potentiometers, calibration is much easier. Tool T-13765 is used to

electronically adjust the board. This advance eliminates the limitations of

mechanical potentiometers and reduces calibration time.

- 9 -

__________________________________________________________________________

1.3 Introduction to AudioScopes

The operation and calibration of all five of these screening audiometers are
explained in this manual.

Important note to Service Personnel

Board Replacement on AudioScope 3:

Welch Allyn manufactures only the AudioScope3 as of Oct. 1986. As of

1996, starting with serial no.967000 a new version AudioScope3 utilizes a

Microcontroller (does not have ASIC) and is calibrated using the T-13765

Calibrator Box. It has digital potentiometers for calibration, not mechanical

pots. All previous models were calibrated using mechanical potentiometer.

Calibration of all types of AudioScopes is explained in this manual. If the

ASIC fails on an AudioScope 3, the whole board will be replaced with the

new board containing the digitally adjustable Microcontroller. This board

will fit the AudioScope3 with no modifications. Unit performance is the

same.

Obsolescence of Single Level AudioScope:

Single Level AudioScopes are over ten years old. Service Parts are not

available. Recalibrations CAN be performed on properly functioning single

level AudioScopes. For failed units, save the lamp, battery, and charging

stand/transformer for use with AudioScope3.

- 10 -

____________________________________________________________________

1.3 Introduction to AudioScopes

AudioScope 3 Handle Controls and features are shown in the figure below.

- 11 -

____________________________________________________________________

1.4a Basic System Description

There are three components to the Welch Allyn AudioScope: the hand
held AudioScope handle, the Charger stand and transformer.

1.4b AudioScope Charging Stand

The charging stand holds the handle and specs and is the interface
between the Handle and the charging current of the wall transformer.
Insertion of the handle into the charging well completes the charging
circuit. An LED illuminates when the handle is in the well and the
charging circuit is complete.

_____________________________________________________________________

1.5 Use of the AudioScope (Screening)

Read pg. 6-8 of Operating Instructions pn230231-2 (shown below) for full

details of the screening procedure.

Note: The following excerpt is only an outline intended for general familiarization by
service personnel. This outline is not intended to replace above referenced Operating
Instructions pn 230231-2.

1. Check that lens is centered in the instrument.

2. Select an area that is relatively quiet and free from distracting sounds.

See page 26 of Operating Instructions for Maximum Permissible
Ambient Noise for the different screening levels.

3. Select appropriate size specula and twist onto instrument. USE ONLY
GRAY-TIPPED WELCH ALLYN AUDIOSPECS.

- 13 -

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1.5 Use of the AudioScope (Screening)

4. Turn AudioScope3 "ON" by sliding the selection switch to the

desired screening level.

5. Instruct patient to respond appropriately to sound. Insert the tip

of the speculum into the ear canal. Position the tip so that the
tympanic membrane or a portion of it can be visualized.

6. Depress START button and observe each tone and the patient's

response. Repeat these steps for opposite ear.

7. Remove instrument from patient's ear and turn off. Return to the

Charging stand. (

REFER TO Operating Instructions

).

continued

_______________________________________________________________________

1.6 Operating Program of Models 23020, 23000, 23040

Single Hearing Level AudioScope

NOTE: Since these models of AudioScopes are well over ten years old, the circuitry
is no longer available. If this circuitry fails, the Single Level AudioScope is no
longer repairable. Recalibrations CAN be performed if the unit is functioning
properly. If the unit fails, however, the lamp, battery, and charging
stand/transformer can be re-used with the AudioScope3.

See Fig. 1-6 Block Diagram of Welch Allyn AudioScope.

• SINGLE HEARING LEVEL AudioScope models (20,25,40 dB) use the same
basic circuitry except for the value of R 21 and the adjustments on

VR2.

Model: Ohms of R21:
20 dB AudioScope = 11 Ohms
25 dB AudioScope = 20 Ohms
40 dB AudioScope = 130 Ohms

AudioScope Service Manual 1.6

__________________________________________________________________________

1.6 Operating Program:

23020, 23000, and 23040

Single Hearing Level AudioScope

Sequence: Cause: Effect:

1. Manual Switch "ON" Lamp "ON", Ready LED "ON"

2. Manual Press "START" U4 activated

3. Logic pin 11 goes to 0v activates LED (500 Hz LED.)

U4 pulls pin 20 to 0v selects resistance between pin
7 of U2 and ground.

this charges C5 produces 500 Hz sine wave at pin 2
of U2

U4 also selects resistance this resistance is adjusted for the
between pin 14 of U4 output amplitude of the 500 Hz tone
and pin 5 of U3. only and is used to control output

amplifier U3.

(Process repeats for the 1000 Hz, 2000 Hz, and 4000 Hz tones.)

4. Logic pin 4 goes to 0v activates LED (1000 Hz LED.)

U4 pulls pin 22 to 0v selects resistance between pins

7 of U2 and ground.
this charges C5 produces 1000 Hz sine wave at pin 2
of U2

U4 also selects resistance this resistance is adjusted for the
between pin 15 of U4 output amplitude of the 1000 Hz tone
and pin 5 of U3. only and is used to control output

amplifier U3.

5. Logic pin 12 goes to 0v activates LED (2000 Hz LED.)

U4 pulls pin 21 to 0v selects resistance between pin
7 of U2 and ground.

this charges C5 produces 2000 Hz sine wave at pin 2
of U2

- 16 -

__________________________________________________________________________

1.6 Operating Program: 23020, 23000, 23040

Single Hearing Level AudioScope continued

Sequence: Cause: Effect:

U4 also selects resistance this resistance is adjusted for the
between pin 17 of U4 output amplitude of the 2000 Hz tone
and pin 5 of U3. only and is used to control output

amplifier U3.

6. Logic pin 3 goes to 0v activates LED (4000 Hz LED.)

U4 pulls pin 1 to 0v selects resistance between pin
7 of U2 and ground.

this charges C5 produces 4000 Hz sine wave at pin 2
of U2

U4 also selects resistance this resistance is adjusted for the
between pin 16 of U4 output amplitude of the 4000 Hz tone
and pin 5 of U3. only and is used to control output

amplifier U3.

7. Logic cycle completes itself Ready LED illuminates

8. Manual switch off unit deactivates, lamps & logic off

- 17 -

__________________________________________________________________________

1.7a Operating Program: 23300 (ASIC TYPE) up to and

including serial no.9609999

Multi-Level AudioScope3 ASIC

The Three Hearing Level AudioScope3 up to and including Serial
Number 960999 uses an ASIC (single application specific integrated
circuit) Microprocessor. This component is not a service part. If the

ASIC Microprocessor should fail, it will be necessary to replace the
Circuit Board/ASIC assembly with the new Microcontroller based
circuit board Part No. This is an easy replacement and does not affect

unit operation. Calibrate the Microcontroller based AudioScope3 with
T-13765 AudioScope Calibrator Box explained in Section 2.7.11

Tone Generation:
External resistors and capacitors are used to generate four
different tones at hearing levels of 20, 25, 40 dBs. The output
amplitude is determined by SW2, which selects one resistor for a
hearing level of 20, 25, or 40 dBs respectively.

Operation begins with switching the unit ON. The examination
halogen lamp illuminates immediately. When the start button is
depressed, the AudioScope begins to generate a sequence of
tones starting with PT of 1000 Hz, which is 20 dB higher than the
manually selected specific hearing level. Then the 1000 Hz, 2000
Hz. , 4000 Hz and 500 Hz tones are generated in that order at the
same hearing level. When the cycle is complete, the AudioScopes
returns to the ready state indicated by the Green "Ready" LED.
The whole cycle is completed in less than 20 seconds.

- 18 -

__________________________________________________________________________

1.7a Operating Program: 23300 (ASIC TYPE) up to and

including serial no.9609999

Multi-Level AudioScope3 ASIC

Sequence: Cause: Effect:

1. Manual Switch "ON" Lamp "ON", Ready LED "ON"

2. Manual Press "START" ASIC activated

3. Logic pin 20 goes low activates PT (PreTone) LED (D6)

PreTone 1kHz sine wave Speaker produces 1 kHz PreTone
appears at ASIC Pin 4
and is amplified and then
applied to speaker
from ASIC Pin 7

(General cycle is repeated for TEST tones: 1000 Hz, 2000 Hz, and 4000 Hz and 500 Hz)

4. Logic ASIC Pin 21 goes low activates 1 kHz LED (D5)
1kHz sine wave Speaker produces 1 kHz Tone
appears at ASIC Pin 3
and is amplified and then
applied to speaker
from ASIC Pin 7

5. Logic ASIC Pin 22 goes low activates 2 kHz LED (D4)
2kHz sine wave Speaker produces 2 kHz Tone
appears at ASIC Pin 6
and is amplified and then
applied to speaker
from ASIC Pin 7

6. Logic ASIC Pin 23 goes low activates 4 kHz LED (D3)
4kHz sine wave Speaker produces 4 kHz Tone
appears at ASIC Pin 5
and is amplified and then
applied to speaker
from ASIC Pin 7

__________________________________________________________________________

1.7a Operating Program: 23300 (ASIC TYPE) up to and

including serial no.9609999

Multi-Level AudioScope3 ASIC

Sequence: Cause: Effect:

7. Logic ASIC Pin 24 goes low activates 500 Hz LED (D2)
500 Hz sine wave Speaker produces 500 Hz Tone
appears at ASIC Pin 2
and is amplified and then
applied to speaker
from ASIC Pin 7

8. Logic cycle completes itself and
activates D1 Ready LED illuminates

9. Manual switch off unit deactivates, lamps & logic off

__________________________________________________________________________

1.7b Operating Program:

no.9670000 and higher)

23300 (Microcontroller type serial

Multi-Level AudioScope3 (Microcontroller/non ASIC)

Sequence: Cause: Effect:

1. Manual Switch "ON" Lamp "ON",Ready LED "ON"

2. Manual Press "START" MICRO activated

3. Logic U4 pin 9 goes to 3 V activates PT (PreTone) LED (D3)

4. Logic U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated

level. This establishes feedback
resistance for U3C.

U4 sequentially toggles pin Generates digital base amplitude
19, 20, 21, 22 sinewave at pin TP10

General cycle is repeated for TEST tones : 1000, 2000, 4000, and 500 Hz.

5. Logic U4 pin 8 goes to 3 V activates 1000 Hz LED (D4)

U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated

level. This establishes feedback
resistance for U3C.

U4 sequentially toggles pin Generates digital base amplitude
19, 20, 21, 22 sinewave at pin TP10

6. Logic U4 pin 7 goes to 3 V activates 2000 Hz LED (D5)

U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated

level. This establishes feedback
resistance for U3C.

U4 sequentially toggles pin Generates digital base amplitude
19, 20, 21, 22 sinewave at pin TP10

- 21 -

__________________________________________________________________________

1.7b Operating Program:

no.9670000 and higher)

23300 (Microcontroller type serial

(continued)

Multi-Level AudioScope3 (Microcontroller/non ASIC)

Sequence: Cause: Effect:

7. Logic U4 pin 6 goes to 3 V activates 4000 Hz LED (D6)

U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated

level. This establishes feedback
resistance for U3C.

U4 sequentially toggles pin Generates digital base amplitude
19, 20, 21, 22 sinewave at pin TP10

8. Logic U4 pin 5 goes to 3 V activates 500 Hz LED (D7)

U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated

level. This establishes feedback
resistance for U3C.

U4 sequentially toggles pin Generates digital base amplitude
19, 20, 21, 22 sinewave at pin TP10

9. Logic cycle completes itself and
activates D2 Ready LED illuminates

10. Manual switch off unit deactivates, lamps & logic off

- 22 -

__________________________________________________________________________

1.8 Technical Specifications

• Charging Stand:

Model# Application:
71123 Charging Stand for all models of AudioScope
Charging Transformers
Model#: Application:
71040 USA and Canada
71036 Australia
71032 Europe
71030 Japan
71034 United Kingdom

• Handles:

Frequencies - 500, 1000, 2000, 4000 Hz +/- 3%
Distortion - Less than 3% total harmonic

distortion as measured at transducer input

Rise/fall times - 20 to 200 msec. as measured between the -1 and -20

dB points
Tone duration - 1.5 seconds +/- 0.2 seconds
Pause between tones Varied between 1.0 and 2.0 seconds
Sound level - Sound levels were established by threshold loudness

balance method to TDH-39 receiver with MX41/AR

cushion per ANSI S3.6-1969 Ref. Thresholds. These

levels were established in an independent study and

are equivalent to standard audiometric headphones.

+/- 3 dB @ 500, 1000, and 2000 Hz, +/- 4 dB @ 4000

Hz.

This corresponds to the following absolute sound pressure levels when the
instrument is coupled to an occluded ear simulator per ANSI Std. No. S3.25­1979:

Freq. For 20 dB HL for 25 dB HL for 40 dB HL
500 28.2 - 31.6 33.2 - 36.6 48.2 - 51.6
1000 26.3 - 28.3 31.3- 33.3 46.3 - 48.3

2000 31.1 - 34.2 36.2 - 39.2 51.2 - 54.2

4000 32.0 - 35.8 37.0 - 40.8 52.0 - 55.8

Lamp - 3.5v Halogen, 20 hr avg. life
Battery - 3.5v nickel cadmium rechargeable pn72300 650

mA/hr.
Continuous use - 50 minutes (approx) between full charge

- 23 -

Section 2:

Service

______________________________________________________________________

- 24 -

2.1 Intent of Service Manual

This manual provides technical assistance to trained service personnel
for diagnosing, repairing, calibrating/testing the AudioScope handle and
Charging Stand and replacing parts listed in Section 2.2. See the table
of contents for a complete listing of manual contents.

Welch Allyn part numbers (PN#), and material numbers (M#), appearing
in this manual are current at the date of publication. Order
replacement parts by referencing your latest bill of materials or parts
catalog. Part number changes, product updates, or new test procedures
should be noted on the appropriate page of this manual by the manual
owner. Notices announcing these changes should be attached to the
manual.

Caution: prior to doing repair work, unplug power cord on
charger to eliminate shock hazard. Use grounding mat and
grounding strap to reduce chances of damage to ASIC in
handle.

Caution

and provide adequate ventilation when using adhesives,
accelerators, and RTV adhesive sealants. Read and follow all
appropriate recommendations in corresponding MSDS sheets.

______________________________________________________________________

when using adhesives: Always wear safety glasses

- 25 -

2.2 Repair Parts for AudioScopes

Note: Order parts from most recent Bill of Materials/Repair:

The attached bill of materials shows replacement parts, which are available
from Welch Allyn.

Part number Description
711427-501 Housing assembly Charging stand
711413 Holder f/handle & specula
711419-501 Rubber feet (set of 4)
711418-501 Base plate assembly
711421 Mounting hardware kit
711420 #6 x 3/4 PHPS HD screw self tap
230035-2 Miniature transducer
230038 Transducer boot
230029-1 Stabilizing grommet
200055-502 Lens holder assembly
230073-505 Housing assembly
230080-502 Cover assembly
230201-501 Electronics module assembly AS3*
710205 Power jack
72300 3.5-volt rechargeable battery
06200 3.5-volt halogen lamp

*Single level AudioScope modules pn 230001-501 are No longer Available.

- 26 -

_____________________________________________________________________

2.3a Lists of Tools/Fixtures/Documents for Service
and Calibration*

* The U.S. Occupational Safety and Health Administration (OSHA)
recommends that audiometers be calibrated annually. Arrangements for
calibration can be made by returning the instrument registration card. In
addition a daily biological check may be performed. This is accomplished
by a person with known normal hearing who listens to the tones for
intensity and quality. There is a moderate fee for recalibration.

Properly trained technicians will need specialized commercially
available test equipment, custom made (Welch Allyn T-tools) specialized
tools and fixtures, basic electronic hand tools and Welch Allyn
specifications and drawings to properly diagnose, calibrate, and repair
the AudioScope and charger base.

Item description: Function: T #&M#
B&K 2231 Modular Precision Sound Level Meter Measures sound output
B&K 4134 1/2" Microphone Sound pick-up
B&K 1625 1/3 to 1 Filter Acoustic filter
B&K Power Supply (6 V.D.C.) Powers B&K 2231
Knowles DB100-R 496 Occluded Ear Simulator Connects T-1393 and T-2011
Knowles DB-009 Teflon washers Seals microphone and DB-100 connection
Fluke 1900A Frequency Counter (3% accuracy) Calibration and testing
Oscilloscope Tektronix 2230A or
Equiv. (storage type) Calibration and testing
ESD mat and wrist-strap Repair
Electronic Technicians hand tools kit General Repair
Digital Volt Ohm Meter Troubleshooting/Repair
PACE Soldering Equipment* Repair T19102-2
*Set iron to 700ºF +/- 27ºF
Rosin Core Solder, .020", 63Sn/37Pb Repair M-31446
G.E. RTV 108 (Clear/Thick) Repair M-30313
Power Supply (0 - 5 VDC @ 1 Amp) Testing T-3769
AudioScope Holding Device holds AudioScope T-1539
Coupling Tool for Microphone Holds AS to DB-100 assembly T-1393
Latchup Box for AudioScope 1 and AudioScope3

with ASIC
Microphone Handle Cover Holds Microphone

AudioScope Calibrator for Microcontroller
digital adjust (non ASIC) T-13765

s/n <=969999

Holds Tones T-9783

to DB-100 T-2011

Charging jack pin-spanner charging jack ring nut tool T-10912

- 27 -

__________________________________________________________________________

2.3a Lists of Tools/Fixtures/Documents for Service
and Calibration*

Drawing# Description Size/# sheets

A02030 Repair Calibration Spec. for AudioScope II B/1 of 1
A00277 Audiometer Handle Test Specifications D/1 of 1
A00984 P.C.B. Test Spec AudioScope II D/1 of 1
A00273 Electronics Module Test Specification D/1 of 2
A00273 Electronics Module Test Specification D/2 of 2
A00985 Audio Module III Test Spec D/1 of 1
A01825 AudioScope III Sound Equipment Calibration

and Setup C/1 of 1
A00942 Charging Stand Electrical Test Spec. A/1 of 1
230230 Audio II Schematic (PCB for ASIC version) D/1 of 1
230215 PC Board Ass'y (for ASIC version D/1 of 1
236630 PCB Schematic (for Microcontroller version) B

Parts catalog pages

230137-3 Nos.23000,23020,23040 AudioScope A/1 of 1
230237-1 No. 23300 AudioScope II and 3 A/1 of 1
711408-2 No. 71123 Charging Stand A/1 of 1

___________________________________________________________________

2.3b Tools and Fixtures Setup for Calibration
AudioScope and AudioScope 3

s/n<=969999 (ASIC)

Figure 2.3b Calibration Set-up for AudioScopes with ASIC

- 29 -

_____________________________________________________________________

2.3c Tools and Fixtures Setup for Calibration
AudioScope 3 s/n >=970000

(Microcontroller)

__________________________________________________________________________

2.4 Training

The AudioScope is a sophisticated audiometric device and must be
serviced and calibrated by trained. They must possess demonstrated
skills in this area using specialized and calibrated sound measuring
equipment. This Service Manual is the basis for delivering competency­based skills training to technicians or service engineers who already
possess knowledge and skills in the use of electronic equipment as listed
in the specialized test equipment Section 2.3. They must also be able to
properly use certain commercially available equipment and hand tools
for diagnosis, calibration, assembly, and board level repairs of the
AudioScope and charger base. See Fig.2.3

This manual provides specific information for diagnosing, repairing,
calibrating and testing the AudioScope handle and Charging Stand. Refer
to the Table of Contents for complete information on the manual.

Use this manual for Self Training. Have an AudioScope system on hand to
help with familiarization and repair practice. Read each complete
repair step before starting hands-on practice.

Use this manual for Group Training. The technician will acquire and
retain service information and service skills for the AudioScope product
because of well prepared and executed training sessions. Conduct
detailed demonstrations of required repair tasks then allow time for
supervised practice. Set up sessions to allow the trainee time to
individually practice all repair procedures. Evaluate trainee progress by
observing trainee performance and then recording it on the appropriate
form. Each trainee must have the opportunity to practice the
procedure(s) after the instructor has demonstrated it.

• Tell them how and why.

• Show them how with explanations.

• Provide for supervised practice by the trainees.

• Record results and conduct follow-up training as necessary.

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_________________________________________________________________________

2.5 Calibration Procedure: Single Level AudioScope

• Incoming bench checks: Prepare the AudioScope for calibration.

2.5.1 ___ Check the tightness of the two slotted screws near battery

positive spring

2.5.2 ___ Check the tightness of the charger jack

2.5.3 ___ Remove RTV from the potentiometers

2.5.4 ___ Check that the sound tube extends at least 1/16" to 1/8" into
the cavity behind the lens. If it does not, move it upwards. Use
fingers. Long nose pliers could bend or crush the sound tube

See Figure 2.5.4 below

• Preparation of Sound Equipment:

2.5.5 ___ Set up your sound equipment as per “AudioScope II Sound
Equipment Calibration and Setup Procedure A01825"

_________________________________________________________________________

2.5 Calibration Procedure: Single Level AudioScope

• Calibration:

Materials Required: Audiometer Handle Test specification A00277

1 sheet (This is the process.)
Electronics Module Test Specification, A00273

2 sheets (These are the specifications.)

Note :A note appearing on the specification reads"Exact Measurements are not
required for 100% inspection". This note does not apply to sound settings.

Adjust the AudioScope according to the printed sound settings and their
tolerances as shown on the print.

Your Sequence: Original Step number from A00277: Modifications if
any:

• 2.5.6 ____ step 1 Start Button Check for smooth

operation.

• 2.5.6 ____ step 2 On/Off Switch

• 2.5.7 ____ step 3 L.E.D.s LED.s must be bright.

• 2.5.8 ____ step 4 Rattle

• 2.5.9 ____ step 7 Cover

• 2.5.10____ step 8 Pneumatic Seal Check seal before sound.

• 2.5.11____ step 5 Sound Level

• 2.5.12____ step 9 Charge

• 2.5.13____ step 10 Lamp Ejector

• 2.5.14____ step 11 Trained Listener

Calibration is complete.
If Single level AudioScope does not take calibration, unit is not serviceable.
Customer should be advised that unit is obsolete, parts are not available .
Lamp, battery, and charging system can be used on new AudioScope 3.

- 33 -

______________________________________________________________________

2.6 Multi Level AudioScopes (AudioScope#)

(ASIC TYPE) up to and including serial no.9609999

• Incoming bench checks: Prepare the AudioScope for calibration.

2.6.1 ___ Check the tightness of the two slotted screws near battery
positive spring

2.6.2 ___ Check the tightness of the charger jack

2.6.3 ___ Remove RTV from the potentiometers

2.6.4 ___ Check that the sound tube extends at least 1/16" to 1/8" into
the cavity behind the lens. If it does not, move it upwards with
long nose pliers taking care not to bend or crush the sound
tube. See Figure 2.5.4

• Preparation of Sound Equipment:

2.6.5 ___ Set up your sound equipment as per "AudioScope II Sound
Equipment Calibration and Setup Procedure A01825"

• Calibration:

Materials Required: Audiometer Handle Test Specifications A00277

1 sheet (This is the process.)
Electronics Module Test Specification, A00985
1 sheet (These are the specifications.)

Note: A note appearing on the specification reads “Exact Measurements are not
required for 100% inspection". This note does not apply to sound settings.

Adjust the AudioScope according to the printed sound settings and their
tolerances as shown on the print.

Sequence: Original Step number from A00277: Modifications if
any:

• 2.6.6 ____ step t1 Start Button Check for smooth

operation.

• 2.6.7 ____ step t2 On/Off Switch

• 2.6.8 ____ step 3 L.E.D.s LED.s must be bright.

• 2.6.9 ____ step 4 Rattle

• 2.6.10____ step 7 Cover

• 2.6.11____ step 8 Pneumatic Seal Check seal before sound.

• 2.6.12____ step 5 Sound Level

• 2.6.13____ step 9 Charge

23300

- 34 -

______________________________________________________________________

2.6 Multi Level AudioScopes 23300 (ASIC TYPE) up to and

including serial no.9609999

• Calibration: Continued

Sequence: Original Step number from A00277: Modifications if
any:

• 2.6.14____ step 10 Lamp Ejector

• 2.6.15____ step 11 Trained Listener

Calibration is complete.

If AudioScope3 (ASIC) does not take calibration, proceed to troubleshooting section.
After repair of the AudioScope3, calibrate. If the unit cannot be repaired, replace the
failed AudioScope 3 ASIC board with a new style Microcontroller based board and
calibrate it according to instructions in Section 2.7.

- 35 -

__________________________________________________________________________

2.7 Calibration Procedure, Multi Level AudioScopes

23300 (MICROCONTROLLER type, serial no.9670000 and higher)

• Incoming bench checks: Prepare the AudioScope 3 for calibration.

2.7.1 ___ Check the tightness of the two slotted screws near battery

positive spring.

2.7.2 ___ Check the tightness of the charger jack.

2.7.3 ___ Check that the sound tube extends at least 1/16" to 1/8" into
the cavity behind the lens. If it does not, move it upwards with
long nose pliers taking care not to bend or crush the sound
tube.

• Preparation of Sound Equipment:

2.7.4 ___ Set up your sound equipment as per "AudioScope II Sound
Equipment Calibration and Setup Procedure A01825"

• Calibration:

Materials Required: Audiometer Handle Test Specifications A00277

1 sheet (This is the process.)
Electronics Module Test Specification, A00985
1 sheet (These are the specifications.)

Note :A note appearing on the specification reads"Exact Measurements are not
required for 100% inspection". This note does not apply to sound settings.

Adjust the AudioScope according to the printed sound settings and their
tolerances as shown on the print.

Your Sequence: Original Step number from A00277: Modifications if
any:

• 2.7.5 ____ step 1 Start Button Check for smooth

operation.

• 2.7.6 ____ step 2 On/Off Switch

• 2.7.7 ____ step 3 L.E.D.s LED.s must be bright.

• 2.7.8 ____ step 4 Rattle

• 2.7.9 ____ step 7 Cover

• 2.7.10____ step 8 Pneumatic Seal Check seal before sound.

__________________________________________________________________________

2.7 Calibration Procedure, Multi Level AudioScopes

23300 (MICROCONTROLLER type, serial no.9670000 and higher)

(continued)

• 2.7.11_____ step 5 Sound Level: Follow steps "a" - "h" below.

a___ Set Run/Cal switch on T-13765 to "RUN" position.

b___ Attach AudioScope Calibration Box T-13765 to

8 pin header connector with orange wire of T-13765 connector
towards crystal.

c___ Turn AudioScope3 On and set to "25 dB"

Observe Green LED. It should be lit.

d___ Place the RUN/CAL switch on the cal box to the "CAL"

position. The green READY light should flash. The orange PT

(PreTone) light should be on.

e___ Use the 1000 Hz filter on the B&K, adjust the PreTone level to
the specified level per A00985 (in Section 5 of this manual),
using the UP and DOWN buttons on T-13765. (The level will
change in prescribed increments each time the buttons are
depressed.

f___ When desired level is set, depress the SAVE & INCR button.

The handle will move to the next tone to be adjusted.

Repeat above sequence for all remaining frequencies. Select correct filter on
B&K.

g___ Switch unit to 40 dB. Repeat above process only checking
readings are in tolerance, but not making adjustments. Switch
unit to 20 dB. Repeat checking.

h___ Switch the RUN/CAL switch RUN position. Microcontroller
AudioScope3 is now calibrated, and will run with new settings.

• 2.7.12____ step 9 Charge

• 2.7.13____ step 10 Lamp Ejector

• 2.7.14____ step 11 Trained Listener

Calibration is complete. If AudioScope3 (Microcontroller) does not take calibration,
proceed to troubleshooting section. After repair of the AudioScope3, calibrate.

- 37 -

Section 3:

Troubleshooting

__________________________________________________________________________

3.1 Troubleshooting AudioScope 3

Complaint Cause

Unit does not turn on.
Green LED does not light.

Low battery voltage

Speaker does not produce
tones.

4-K range does not calibrate.

Housing fails air seal test.

Halogen lamp does not light.

Handle does not charge.

Excessive battery drain.

Low battery voltage.

Cold solder joint at battery
terminal.

Defective contact in power jack
will not close when charge plug
is removed.

Defective power jack

Defective charging circuit

Cold solder joint at speaker or
wire to PCB.

Broken speaker wire

Defective speaker

No voltage at TP2

Defective speaker

Gasket not seated correctly

Leaking Lens Gasket

Leaking Stabilizing Grommet

Defective housing

Low battery voltage.

Defective halogen lamp.

Bent or broken charging
contacts in charging well.

Shorted lamp.

s/n <=969999 (ASIC)

Corrective Action

Substitute with charged test
battery and retest.
Replace battery. Retry.
If green LED remains unlit,

replace board.

Restore connection by
reflowing joint (using T19102-

2).

Replace power jack.

Replace housing.

Inspect circuit. Restore.

Restore connection by
reflowing joint (using T19102-

2).

Repair wire.

Replace speaker.

Replace Board

Replace Speaker. If still does
not cal, replace PCB and retest.

Remove lens assembly and
rotate 180 degrees. Reinstall
and retest.

Replace housing.

Replace

Replace housing.

Recharge or replace battery.

Replace.

Re-shape contact(s)
Replace Housing Assembly

Replace Lamp.

- 39 -

__________________________________________________________________________

3.2 Troubleshooting AudioScope 3 s/n >=970000

(MICROCONTROLLER / NON-ASIC)

Complaint

Unit does not turn on.
Green LED does not light.

Low battery voltage

Speaker does not produce
tones.

Does not calibrate at a
particular frequency.

Does not calibrate at any
frequency.

PRETONE L.E.D. is blinking

Housing fails air seal test.

Halogen lamp does not light.

Handle does not charge.

Excessive battery drain.

Cause

Low battery voltage.

Cold solder joint at battery
terminal.

Defective contact in power jack
will not close when charge plug
is removed.

Defective power jack

Defective charging stand

Cold solder joint at speaker or
wire to PCB.

Broken speaker wire

Defective speaker

No voltage at TP2

Defective speaker

Call box plugged in backwards. Plug cal box connector into PCB

Unit needs calibration.

Gasket not seated correctly

Leaking Lens Gasket

Leaking Stabilizing Grommet

Defective housing

Low battery voltage.

Defective halogen lamp.

Bent or broken charging
contacts in charging well.

Shorted lamp.

Corrective Action

Substitute with charged test
battery and retest.
Replace battery. Retry. If green
LED remains unlit, replace
board.

Restore connection by
reflowing joint (using T19102-

2).

Replace power jack.

Replace housing.

Check circuit and restore.

Restore connection by reflowing

joint (using T19102-2).

Repair wire.

Replace speaker.

Replace Board

Replace Speaker. If still does

not cal, replace PCB and retest.

with orange wire towards
crystal.

Calibrate

Remove lens assembly and
rotate 180 degrees. Reinstall.

Replace housing.

Replace.

Replace housing.

Recharge or replace battery.

Replace lamp.

Re-shape contact(s)
Replace Housing Assembly

Replace Lamp.

- 40 -

- 41 -

Section 4:

Disassembly and Repair

- 42 -

__________________________________________________________________________

4.1 Disassembly Procedure, AudioScope3

Caution: The battery and lamp become very hot during operation.

Allow ten minutes of cool-down time before opening unit.

Abstract: The Printed Circuit Board and power jack are easily removed from the
handle housings. The spring steel charger well contacts on the handle are spring steel
and will snap when attempting to spread them too far. The mini-transducer (speaker)
and sound tube are easily removed from the board without removing the board from
the handle housing. The rubber gasket that seals the sound tube to the AudioScope
head is called a Stabilizing Grommet. This grommet can be changed if it leaks air. Air
leaks can deteriorate the performance of the instrument. Air leaks are a result of
rough handling and resultant broken seals in the housing halves, or bad gaskets around
the lens and or the stabilizing grommet.
Lens gaskets are installed during assembly before right and left side cases are bonded
together. Replacement is not covered in this manual.

4.1.1 Prepare the unit for disassembly or service

___ Turn the LOCKED/OPEN knob on the bottom of the AudioScope to

OPEN (the two lines should meet together at the bottom). Use a
flathead screwdriver or coin.

___ Slide the top of the housing backwards, exposing the battery and

board.

___ Lift the battery out by pulling upwards on the positive end.
___ Remove the lamp by pressing the blue button on the board.

4.1.2 Speaker removal

___ Do not try to pull the sound tube out of the boot since the boot end of

the sound tube is flared.

___ Gently push the speaker boot (containing the speaker) off of the metal

spring clip.

___ Gently pull the speaker out of the boot.
___ Note the position of the red and black wires relative to the imprinting

on the speaker and un-solder them (using T19102-2).

4.1.3 Speaker replacement

___ Solder red and black wires to new speaker in the order noted

above (in step 4.1.3) .

___ Gently press the speaker into the speaker boot.

- 43 -

__________________________________________________________________________

4.1 Disassembly Procedure, AudioScope3

(continued)

4.1.4 Stabilizing Grommet removal *(sound tube gasket near lamp)

___ Slide the speaker boot off of the clip and pull the sound tube out of

the stabilizing grommet.

___ Peel the old grommet out of the ring at the end of the board.
___ Install new grommet by carefully pressing it into the ring.
___ Insert the sound tube into the stabilizing grommet and then slide the

speaker boot (containing the speaker) onto the spring clip.

___ Adjust the height of the sound tube so that approximately 1/8"

extends into the housing behind the lens. See Figure 2.5.4

___ Perform a leak check on the instrument after replacing stabilizing

grommet.

4.1.5 Printed circuit board removal

___ Unscrew two screws at the positive terminal end of the circuit board.
___ Pull the board towards the battery compartment and carefully lift the

board out.

4.1.6 Power jack removal

___ Unscrew jack ring nut with T-10912
___ Un-solder (using T19102-2) three connections on back of jack.
___ Remove jack from housing.

Reassembly

4.1.7 Install power jack

___ Put jack through hole in housing so that three tabs line up with

components.

___ Restore connections by soldering (using T19102-2) three components to

tabs on jack.

4.1.8 Place board into housing

___ Place the switch on the housing on the "off" position.
___ Place the switch mounted on the circuit board to the 40 dB position,

toward the yellow LED.

___ Position the sound tube gasket into the hole in head of the instrument.
The 5/16" round rubber ring will line up with the end of the fiber
optic bundle.
___ Gently push the board back into its original position. The tab of the

switch will engage the cavity of the switch button.

- 44 -

__________________________________________________________________________

4.1 Disassembly Procedure, AudioScope3

(continued)

4.1.9 Prepare the unit for functional check and calibration.

___ Place a known good lamp into the unit.
___ Place a known good, charged battery into the unit.
___ Perform full functional check per A specifications
___ Check frequency and amplitude / Calibrate unit.

- 45 -

__________________________________________________________________________

4.2 Disassembly Procedure, Charging Stand.

Abstract: The Charging Stand disassembles to three main components: the base
plate, the holder, and the housing assembly. If the internal circuit board fails, replace
the housing assembly. Bent charging contacts cannot be replaced since they are heat­staked into the housing assembly.

4.2.1 Prepare charger stand unit for disassembly.

___ Unplug charging transformer from mains.
___ Remove specula.

4.2.2 Base plate assembly removal.

___ Unscrew four screws holding the base plate assembly to the housing

assembly.

___ Push the base out of the housing (if it sticks) with the handle of a

screwdriver or small hammer.

___ Lift the holder (top portion of the charging stand) out of the housing.

4.2.3 Rubber feet.

___ Push old rubber feet out of base plate.
___ Push replacement feet into holes in base plate.

4.2.4 Reassemble.

___ Slide holder into housing assembly. Do not crush contacts.
___ Place base into housing assembly.
___ Attach base to housing assembly with four screws.

4.2.5 Test

___ Connect a known good charger to the Charging Stand jack.
___ Put a "known good" handle into the charging well.
___ Charging light will light if stand is functioning normally.

- 46 -

Section 5:

Drawings / Test Specifications

- 47 -

- 48 -

__________________________________________________________________________

5.1 Drawings and Test Specifications

This section contains the following documents for service and calibration

of AudioScopes.

Drawing# Description Size/# sheets

A02030 Repair Calibration Spec. for AudioScope II B/1 of 1
A00277 Audiometer Handle Test Specifications D/1 of 1
A00984 P.C.B. Test Spec AudioScope II D/1 of 1
A00273 Electronics Module Test Specification D/1 of 2
A00273 Electronics Module Test Specification D/2 of 2
A00985 Audio Module III Test Spec D/1 of 1
A01825 AudioScope III Sound Equipment Calibration

and Setup C/1 of 1
A00942 Charging Stand Electrical Test Spec. A/1 of 1
230230 Audio II Schematic (PCB for ASIC version) D/1 of 1
230215 PC Board Ass'y (for ASIC version D/1 of 1
236630 PCB Schematic (for Microcontroller version) B

Parts catalog pages

230137-3 Nos.23000,23020,23040 AudioScope A/1 of 1
230237-1 No. 23300 AudioScope II and 3 A/1 of 1
711408-2 No. 71123 Charging Stand A/1 of 1