® 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 PN: 230260 Rev. B Welch Allyn, Inc. 4341 State Street Road P.O.
__________________________________________________________________________ Revision History ECN#/ ECO# Date Section Title Author Description 5/31/96 1 General Info. RJS Intro of Document A 5/31/96 2 Service RJS Intro of Document A 5/31/96 3 Troubleshooting RJS Intro of Document A 5/31/96 4 Disassembly/Rep air RJS Intro of Document A 5/31/96 5 Drawings/Specs.
______________________________________________________________________________________ Table of Contents Cover Page Revision Page Table of Contents Sub Sect SECTION 1: General Information To Service Personnel Limited Warranty Introduction to AudioScopes Figure 1.3 AudioScope Handle Controls Basic System Description (Fig.1.4a Basic System) Basic System Description (charging stand) Use of the AudioScope (Screening) Operating Program 1-Lev (Fig 1.
____________________________________________________________________________________ Table of Contents conti nued SECTION 5: Drawings/ Test Specifications Manilla Pockets contain 17" x 22" drawings. 5.1 Drawing# Description A02030 A00277 A00984 A00273 A00273 A00985 A01825 Repair Calibration Spec. for AudioScope II Audiometer Handle Test Specifications P.C.B.
Section 1: General Information
____________________________________________________________________________________ 1.1 To Service Personnel Read and understand the AudioScope operating instructions manual pn. 2302312. 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.
______________________________________________________________________ 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.
___________________________________________________________________ 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).
__________________________________________________________________________ 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.
____________________________________________________________________ 1.3 Introduction to AudioScopes AudioScope 3 Handle Controls and features are shown in the figure below.
____________________________________________________________________ 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.
_____________________________________________________________________ 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.
_____________________________________________________________________ 1.5 Use of the AudioScope (Screening) continued 4. 5. 6. 7. Turn AudioScope3 "ON" by sliding the selection switch to the desired screening level. 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. Depress START button and observe each tone and the patient's response.
_______________________________________________________________________ 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.
__________________________________________________________________________ 1.6 Operating Program: 23020, 23000, and 23040 Single Hearing Level AudioScope Sequence: 1. Manual Cause: Switch "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. produces 500 Hz sine wave at pin 2 of U2 this charges C5 U4 also selects resistance between pin 14 of U4 and pin 5 of U3.
__________________________________________________________________________ 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. Effect: this resistance is adjusted for the output amplitude of the 2000 Hz tone 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.
__________________________________________________________________________ 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.
__________________________________________________________________________ 1.7a Operating Program: 23300 (ASIC TYPE) up to and including serial no.9609999 Multi-Level AudioScope3 ASIC Sequence: 1. Manual Cause: Switch "ON" Effect: Lamp "ON", Ready LED "ON" 2. Manual Press "START" ASIC activated 3.
__________________________________________________________________________ 1.7a Operating Program: 23300 (ASIC TYPE) up to and including serial no.9609999 Multi-Level AudioScope3 ASIC Sequence: 7. Logic Cause: ASIC Pin 24 goes low 500 Hz sine wave appears at ASIC Pin 2 and is amplified and then applied to speaker from ASIC Pin 7 Effect: activates 500 Hz LED (D2) Speaker produces 500 Hz Tone 8. Logic cycle completes itself and activates D1 Ready LED illuminates 9.
__________________________________________________________________________ 1.7b Operating Program: 23300 (Microcontroller type serial no.9670000 and higher) Multi-Level AudioScope3 (Microcontroller/non ASIC) Sequence: 1. Manual Cause: Switch "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.
__________________________________________________________________________ 1.7b Operating Program: 23300 (Microcontroller type serial no.9670000 and higher) (continued) Multi-Level AudioScope3 Sequence: 7. Logic (Microcontroller/non ASIC) Cause: U4 pin 6 goes to 3 V Effect: activates 4000 Hz LED (D6) U4 pulses pin 4 U4 ramps U5 (digital pot) to calibrated level. This establishes feedback resistance for U3C.
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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.
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.
_____________________________________________________________________ 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.
__________________________________________________________________________ 2.3a Lists of Tools/Fixtures/Documents for Service and Calibration* Drawing# Description A02030 A00277 A00984 A00273 A00273 A00985 A01825 Repair Calibration Spec. for AudioScope II B/1 of 1 Audiometer Handle Test Specifications D/1 of 1 P.C.B.
___________________________________________________________________ 2.3b Tools and Fixtures Setup for Calibration AudioScope and AudioScope 3 s/n<=969999 (ASIC) Figure 2.
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__________________________________________________________________________ 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.
_________________________________________________________________________ 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.
_________________________________________________________________________ 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.
______________________________________________________________________ 2.6 Multi Level AudioScopes (AudioScope#) 23300 (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.
______________________________________________________________________ 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.
__________________________________________________________________________ 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.
__________________________________________________________________________ 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.
Section 3: Troubleshooting
__________________________________________________________________________ 3.1 Troubleshooting AudioScope 3 s/n <=969999 (ASIC) Complaint Cause Corrective Action Unit does not turn on. Green LED does not light. Low battery voltage. Substitute with charged test battery and retest. Replace battery. Retry. If green LED remains unlit, replace board. Cold solder joint at battery terminal. Restore connection by reflowing joint (using T191022).
__________________________________________________________________________ 3.2 Troubleshooting AudioScope 3 s/n >=970000 (MICROCONTROLLER / NON-ASIC) Complaint Cause Corrective Action Unit does not turn on. Green LED does not light. Low battery voltage. Substitute with charged test battery and retest. Replace battery. Retry. If green LED remains unlit, replace board. Cold solder joint at battery terminal. Restore connection by reflowing joint (using T191022).
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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.
__________________________________________________________________________ 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.
__________________________________________________________________________ 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.
__________________________________________________________________________ 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.
Section 5: Drawings / Test Specifications - 47 -
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__________________________________________________________________________ 5.1 Drawings and Test Specifications This section contains the following documents for service and calibration of AudioScopes. Drawing# Description Size/# sheets A02030 A00277 A00984 A00273 A00273 A00985 A01825 A00942 230230 230215 236630 Repair Calibration Spec. for AudioScope II B/1 of 1 Audiometer Handle Test Specifications D/1 of 1 P.C.B.
