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

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Revision History

ECN#/
ECO#	Revision	Date	Section	Title	Author	Description
5-32904		5/31/96	1	General Info.	RJS	Intro of
	A					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	RJS	Intro of
				air		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.
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

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Table of Contents conti nued

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

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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

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.

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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:
1.	Manual	Switch "ON"
2.	Manual	Press "START"
3.	Logic	pin 11 goes to 0v
		U4 pulls pin 20 to 0v
		this charges C5

U4 also selects resistance between pin 14 of U4 and pin 5 of U3.

Effect:

Lamp "ON", Ready LED "ON"

U4 activated

activates LED (500 Hz LED.)

selects resistance between pin 7 of U2 and ground.

produces 500 Hz sine wave at pin 2 of U2

this resistance is adjusted for the output amplitude of the 500 Hz tone 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
	U4 pulls pin 22 to 0v
	this charges C5
	U4 also selects resistance
	between pin 15 of U4
	and pin 5 of U3.
5. Logic	pin 12 goes to 0v
	U4 pulls pin 21 to 0v
	this charges C5

activates LED (1000 Hz LED.)

selects resistance between pins 7 of U2 and ground.

produces 1000 Hz sine wave at pin 2 of U2

this resistance is adjusted for the output amplitude of the 1000 Hz tone only and is used to control output amplifier U3.

activates LED (2000 Hz LED.)

selects resistance between pin 7 of U2 and ground.

produces 2000 Hz sine wave at pin 2 of U2

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1.6 Operating Program: 23020, 23000, 23040

Single Hearing Level AudioScope continued

Sequence:		Cause:
		U4 also selects resistance
		between pin 17 of U4
		and pin 5 of U3.
6.	Logic	pin 3 goes to 0v
		U4 pulls pin 1 to 0v
		this charges C5
		U4 also selects resistance
		between pin 16 of U4
		and pin 5 of U3.
7.	Logic	cycle completes itself
8.	Manual	switch off

Effect:

this resistance is adjusted for the output amplitude of the 2000 Hz tone only and is used to control output amplifier U3.

activates LED (4000 Hz LED.)

selects resistance between pin 7 of U2 and ground.

produces 4000 Hz sine wave at pin 2 of U2

this resistance is adjusted for the output amplitude of the 4000 Hz tone only and is used to control output amplifier U3.

Ready LED illuminates

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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