Welch Allyn AudioScope 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

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Revision History
ECN#/
ECO#
Revision
Date Section Title Author Description
5-32904
A
5/31/96 1 General Info. RJS
Intro of
Document
5-32904
A 5/31/96 2 Service RJS
Intro of
Document
5-32904
A 5/31/96 3 Troubleshooting RJS
Intro of
Document
5-32904
A 5/31/96 4
Disassembly/Rep
air
RJS
Intro of
Document
5-32904
A 5/31/96 5 Drawings/Specs. RJS
Intro of
Document
1001574 B 6/17/04 Soldering BSW
Added Soldering
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.

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Table of Contents
Sub Sect Pg.
CoverPage 1
RevisionPage 3
TableofContents 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

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Table of Contents conti nu ed
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

Section 1:
General Information

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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
C
CA AU UT TI IO ON N: : P PR RI IO OR R T TO O D DO OI IN NG G R RE EP PA AI IR R W WO OR RK K, , U UN NP PL LU UG G P PO OW WE ER R C CO OR RD D O ON N C CH HA AR RG GE ER R T TO O
E
EL LI IM MI IN NA AT TE E S SH HO OC CK K H HA AZ ZA AR RD D. . U US SE E G GR RO OU UN ND DI IN NG G M MA AT T A AN ND D G GR RO OU UN ND DI IN NG G S ST TR RA AP P T TO O
R
RE ED DU UC CE E C CH HA AN NC CE ES S O OF F D DA AM MA AG GE E T TO O A AS SI IC C I IN N H HA AN ND DL LE E. .

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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

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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.

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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.

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1.3 Introduction to AudioScopes
AudioScope 3 Handle Controls and features are shown in the figure below.

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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.

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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.

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1.5 Use of the AudioScope (Screening) continued
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).

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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

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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
7ofU2andground.
this charges C5 produces 500 Hz sine wave at pin 2
ofU2
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
amplifierU3.
(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
ofU2
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
amplifierU3.
5. Logic pin 12 goes to 0v activates LED (2000 Hz LED.)
U4 pulls pin 21 to 0v selects resistance between pin
7ofU2andground.
this charges C5 produces 2000 Hz sine wave at pin 2
ofU2

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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
amplifierU3.
6. Logic pin 3 goes to 0v activates LED (4000 Hz LED.)
U4 pulls pin 1 to 0v selects resistance between pin
7ofU2andground.
this charges C5 produces 4000 Hz sine wave at pin 2
ofU2
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
amplifierU3.
7. Logic cycle completes itself Ready LED illuminates
8. Manual switch off unit deactivates, lamps & logic off

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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.

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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

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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