Welch Allyn Micro Tymp 1 User manual

SERVICE MANUAL
Micro Tymp
Tympanometric System
23600 handle, 71130 printer charger
Copyright 1995
Welch Allyn Co.
4341 State Street Road Welch Allyn
P.O. Box 220
Skaneateles Falls, NY 13153-0220 Service manual pn236261 Rev.D 6/95
originator: RJS
ECN#5-30727 pg 1

Micro Tymp 1 Service Manual
Table of Contents
SECTION 1: General Information ..................... Sect. pg
To Service Personnel.............................. 1.1 3
Limited Warranty ................................... 1.2 4
Basic System Description....................... 1.3 5
Basic System Operation (Fig.1) ............. 1.4 6
Block Diagram of MT 1 Program .......... 1.5 7
Specifications.......................................... 1.6 8
SECTION 2: Service
Repair Methodology & Service Parts..... 2.1 9
Required Tools and Materials ................ 2.2 10
Training and Manual Components ......... 2.3 11
Calibration Procedure............................. 2.4 12
High Altitude Modification .................... 2.5 20
SECTION 3: Problem Solving
Troubleshooting...................................... 3.1 21
SECTION 4: Disassembly and Repair
Handle disassembly ................................ 4.1 42
Handle re-assembly ................................ 4.2 46
SECTION 5: Maintenance
Printer charger disassembly.................... 5.1 53
Printer charger re-assembly.................... 5.2 55
SECTION 6: Drawings
Procedure for Calibrator testing ............. 6.1 56
Drawings & listings ................................ 6.2 57
CAUTION: USE GROUNDING MAT AND GROUNDING STRAP WHEN SERVICING STATIC
SENSITIVE ELECTRONIC COMPONENTS. (6 CMOS IN HANDLE AND 1 CMOS IN
PRINTER CHARGER)
Copyright 1995
Welch Allyn Co. WA R
4341 State Street Road Welch Allyn
P.O. Box 220
Skaneateles Falls, NY 13153-0220 Service manual pn236261 Rev.D 6/95
originator: RJS
ECN#5-30727 pg 2

Section 1.1 General Information
To Service Personnel:
Read and understand the MicroTymp 1 Operating Instructions manual PN.236084-2.
The information in the Operating Instructions and Service Manual are subject to change
without notice and should not be construed as a commitment by Welch Allyn, Inc.
Welch Allyn assumes no responsibility for any errors that may appear in this manual. If
the product and/or its operation varies significantly from any description herein, please
contact: Welch Allyn Medical Products Division Technical Service Department, 4341
State Street Road, Skaneateles Falls, New York, 13153-0220, U.S.A., [phone],
or [phone].
This product has been designed to provide a high degree of safety and reliability. How-
ever, we can not guarantee against the deterioration of components due to aging and
normal wear. All service and repairs must be performed by authorized Welch Allyn
personnel or agents, using approved Welch Allyn replacement parts and approved pro-
cess materials. Failure to do so will invalidate the product warranty. Please refer to the
product warranty for specific coverage.
READ AND UNDERSTAND customer comments and complaints on accompanying documentation
(P.O. or other correspondence).
If an injury, illness to patient or user, or hazardous malfunction has occurred or is suspected, PROCEED
NO FURTHER! DO NOT disassemble, repair, adjust, or in any way alter the MicroTymp or the
printer charger base... instead, notify your supervisor at once. Give them all accompanying paperwork
and any information you might have on the return. They will take appropriate action according to Welch
Allyn policy. Check customer service records to determine if this MicroTymp requires or has received
any applicable retrofit modifications, improvements, or inspections, and perform these if required.
INSPECT AND TEST it before and after it is repaired. Documentation should include: general
condition, defects, missing components and labels, electrical, functional and mechanical problems.
Operate the returned instrument to try to duplicate the customer's complaint before and after it is
repaired.
Welch Allyn, Inc.
Medical Products Division
4341 State Street Road
Skaneateles Falls, New York 13153-0220
USA
1 800 669-9771
[phone]
pg 3

Section 1.2 General Information
Limited Warranty
Welch Allyn warrants the MicroTymp and Printer/Charger, when new, to be free of
defects in material and workmanship and to perform in accordance with manufacturer’s
specifications for a period of one year from the date of purchase from Welch Allyn or its
authorized MicroTymp distributors or agents. Welch Allyn will either repair, replace or
recalibrate any components found to be defective or at variance from the manufacturer’s
specifications within this time at no cost to the customer, except for transportation ex-
penses. 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 MicroTymp 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. The warranty on the MicroTymp can be extended to
a three year period provided the instrument is returned for recalibration annually. Pur-
chase date determines warranty and recalibration requirements. No other express war-
ranty is given. Submission of instrument registration card is required for warranty
validation.
To receive service assistance or to ask questions regarding this warranty, please call or
write: Welch Allyn Technical Services Dept.
Welch Allyn, Inc.
Medical Products Division
4341 State Street Road
Skaneateles Falls, New York 13153 USA
1 [phone] or [phone]
pg 4

Section 1.3 General Information
Introduction
The Welch Allyn Micro Tymp Tympanometric System enables the practitioner to per-
form an objective test of the middle ear function. It provides fast and painless measure-
ment on prevalent disease. Results appear instantly on the liquid crystal display and can
be stored and printed in the Printer/Charger.
Basic System Description
There are two major components to the Micro Tymp Tympanometric System: the hand
held Micro Tymp handle, and the Printer/Charger. The handle utilizes a probe with
three portholes: one which leads to a pump and pressure transducer for air pressure, one
for delivering sound from a speaker, and one which leads to a microphone for picking up
the sound. These are clearly shown in Figure 1-1 block diagram.
*A 226 Hz probe tone is introduced in the sealed ear canal by a miniature loudspeaker.
*A microphone records and monitors the sound pressure produced in the ear canal.
*The sound level is maintained at a constant 85 dB SPL (SOUND PRESSURE LEVEL)
throughout a test. Therefore, when the amount of sound absorbed by the middle ear
increases, the speaker must be driven harder to maintain the correct SPL.
*Pressure in the ear canal is changed with a miniature pump. The pressure transducer
monitors this pressure and sends this information to the microprocessor so that it can
control the pump.
*The voltage to the speaker determines its output. Therefore, acoustic admittance is
proportional to speaker voltage.
*As pressure in the ear canal is changed throughout a test, the microprocessor com-
putes acoustic admittance and plots it out.
The Printer Charger stand contains the print head, power supply PCB, fuses, switch
assembly, and microcomputer.
pg 5

Section 1.4 General Information
FIGURE 1-1...BLOCK DIAGRAM OF WELCH ALLYN
MICRO TYMP.
Operation
1. Insert the Micro Tymp handle into the patient’s ear.
Press the tip firmly against the ear canal opening to insure seal.
2. Push START/RUN button. Micro Tymp automatically measures and displays results
on the LCD. Push memory button (Ear symbol) and repeat for other ear.
3. Return instrument to the Printer/Charger. Push PRINT
button for double-ear print out. Data transfers immediately and prints out for single
or multiple copies. (REFER TO OWNER’S GUIDE).
pg 6

Section 1.5 General Information
MICRO TYMP 1 OPERATING PROGRAM
PUSH BUTTON, MT 1 ACTIVATES
PROPER PRESSURE READING . . .
COMPLIANCE READING AT FULL LEVEL
FAST FLASHING OPEN SYMBOL
CAVITY ON PROBE TIP? (VOLUME CHANGE)
PROPER MAGNITUDE OF CHANGE?
START PRESSURIZATION < . . .
REACH 200 daPa? . . .
PRINT VALID VOLUME? . . .
BEGIN TO PRINT GRAPH
REACH -300 daPa? . . .
OPEN VALVE/RETURN PUMP TO START POSITION
DISPLAY PRESSURE RANGE ERROR
WAITING FOR NEXT CYCLE ('TYMP")
DISPLAY SAVE DATA GRAPH*
COMPLETE ADMITTANCE CURVE?
FAST FLASHING BLOCK SYMBOL
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
YES
NO
LOW (50-CF) . . . LEAK SYMBOL
LOWER (40-50) . . . SLOW FLASH BLOCK SYMBOL
LOWEST (<40) . . . FAST FLASH BLOCK SYMBOL
NO
NO
NO
NO
NO
NO
TOO SMALL
TOO LARGE SLOW FLASHING BLOCK SYMBOL
SLOW FLASHING OPEN SYMBOL
LEAK SYMBOL RETURN PUMP TO START POSITION
NOT ENOUGH
TOO MUCH
*GRAPH DOES NOT HAVE TO HIT THE BASELINE. HOWEVER, IT MUST COMPLETE THE ADMITTANCE CURVE.

pg 7
Section 1.6 General Information
Specifications
The specifications for the Welch Allyn Micro Tymp are as follows:
Printer Charger base Power requirements:
Model#: Input-volts/amps voltage range
71130 120/.1 110-130
71132 230/.06 210-250
71133 100/.11 90-110
71134 230/.06 210-250
71136 230/.06 210-250
Probe tone:
Frequency 226 Hz
Amplitude 85 dB +-3 dB re 20 uPa in an ANSI HA-1 (2cc)
coupler.
Admittance Range:
0.2 to 4.0 mmho total
0 to 1.5 mmho for Ya
0.2 to 2.0 cc for +200 Vea
Display Resolution:
0.1 mmho for Ya
0.2 cc for +200 Vea
20 dapa for pressure
Pressure Range:
+200 to -300 daPa
Accuracy:
+- 15% or 10 daPa, whichever is greater.
Compensation:
Auto-Zero with each test cycle.
Pump: Direction of sweep: positive to negative
Speed: 200 +/-20 daPa/second during acquisition.
pg 8

Section 2.1 Service
Repair Methodology:
This manual provides technical assistance to Welch Allyn Inc. authorized service
representatives for diagnosing, repairing, and testing the Micro Tymp handle and
printer charger base and replacing parts as listed below. The manual covers:
fault/cause analysis tables, step by step disassembly / reassembly procedures,
repair, adjustment, and re-test procedures.
Order Service Parts from a current Welch Allyn
Bill of Materials/Repair:
This list provides an overview of available service parts:
pressure transducer assembly door
battery compartment assembly printer bottom housing assy
front housing assembly back housing
piston/diaphragm assembly flex circuit-overall
electrolytic capacitor rechargeable battery 7.2v
reference label fiber strip
phps screw 4-40x.312"&.750" .5cc check well
#6x3/4"phps hd self-tap screw right angle header
paper spindle LB 1256 head driver
power cord assy releasable cable tie
printer and power supp. PCB assy. paper installation label
base plate assy fuse 125ma slo-blo
top housing assy printer
printer head platen bar
reset controller cord guard
self tapping screw. 37 op trans.amp ca3080
1/8 w 5% 62k resistor battery cover assy
pump assy voltage invertor ic
1206 chip capacitor 2-56x.56" bdg hd mach sc
IC - signal processor H12340 microprocessor
IC - LCD driver 32k Hz crystal
5v regulator overcurrent protector
analog/digital converter logo label
trim resistor 1/4 r 10k trim resistor 1/4 r 500
trim resistor 1/4 r 5k trimmer resistor 1/4rnd 50k
trim resistor 1/4 r 200k 2.56 php fl hd mach.sc.
0805 chip resistor 62k dual power op-amp
multi-turn trim resist. so transistor 2N3904
so transistor 2N39906 so transistor 2N4403
battery contact insulator
battery contact r.h. op amp dual bi-fet tlc272CP
battery contact l.h. speaker boot assy.
microphone boot assy. zebra strip
connector phps screw
pg 9

Section 2.2 Service
Required Tools and Fixtures for Service
Specialized test equipment and standard tools are required for diagnosis, calibration,
assembly, and board level repairs.
COMMERCIALLY AVAILABLE EQUIPMENT/TOOLSQUANTITY REQUIRED:
BRUEL & KJAER MODEL 2231X SOUND METER (1)
B&K 1625 1/3 - 1 OCTAVE FILTER SET (1)
B&K ZC0020 INPUT STAGE TO BK2231 (1)
B&K A00027 EXTENSION CABLE (1)
B&K Z19100/WH2014 INTERFACE MOD. 25 PIN (1)
B&K 4144 1" MICROPHONE (1)
B&K POWER SUPPLY FOR ABOVE (1)
B&K DB0375 1" MICROPHONE ADAPTOR (1)
DVOM (BECKMAN310/4410 OR EQUIV.) (1)
OSCILLOSCOPE (STORAGE) (1)
ELECTRONIC SOLDERING STATION (1)
ELECTRONICS AND JEWELERS SCREWDRIVER SET (1)
LEAD STRAIGHTENING PLIERS (UTICA#U508) (1)
SCREWDRIVER (#1 PHILLIPS#2501) (1)
SCREWDRIVER (#2 PHILLIPS#2502) (1)
SCREWDRIVER (7/32"Flat Blade,PH#143-36) (1)
WIRE CUTTER (Xcelite 107CG) (1)
WIRE STRIPPER (Xcelite 105SCG) (1)
LONG NOSE PLIERS (XCELITE 51CG) (1)
HEMOSTATS (2)
GROUND MAT (1)
GROUNDING STRAP FOR TECHNICIAN (1)
TWEEZERS (STRAIGHT) (1)
SMALL DRILL BIT SET (1)
COTTON TIPPED SWABS (LINT FREE) (1)
WELCH ALLYN CUSTOM TOOLS AND MATERIALS:QUANTITY REQUIRED:
T-3281 TYMP CALIBRATOR (1)
(includes dual power supply and leads)
T-5657 PRESSURE APPLICATOR BOX (1)
T-5609 TYMP HOLDING FIXTURE (1)
T-5744 FIXED CAVITY 5 piece set (1)
includes:.2 cc, .5 cc, 1 cc, 2 cc, 3 cc
T-3382 HA-1 ADAPTOR BRASS (1)
T-5734 DIAPHRAGM PLACEMENT TOOL (TUCKER) (1)
M-31446 ROSIN CORE SOLDER(.020")63SN/37PB (1)
M-30313 G.E.RTV108 CLEAR Thick (1)
M-30327 G.E.RTV118 CLEAR Surface Leveling (1)
M-13069 RED GLYPTOL VARNISH (1)
M-30342 LOCKTITE ACCELERATOR (1)
M-30341 LOCKTITE BLACK MAX ADHESIVE (1)
*CAUTIONWHENUSINGADHESIVES pg 10
*
*

Section 2.3 Service
Training
When reading this manual for the first time, have a Micro Tymp 1 and Printer/Charger
base available for reference and practice. But first, read each complete repair step on
what to do and how to do it before starting the repair or practice.
Micro Tymp Service Training should consist of detailed demonstrations of required
repair tasks, such as opening up the cases and calibrating. Practice on scopes using actual
repair fixtures, tools and materials. Assess skill development by observing trainee prac-
tice on actual equipment. Set up sessions to allow the trainee time to individually prac-
tice all Micro Tymp repair procedures. The ability of the technician to develop and
retain new skills is in great part dependent on well prepared training exercises. Each
trainee must have the opportunity to practice the procedure(s) after it has been demon-
strated by the instructor.
More detailed background product information is found in the APPENDIX section and as
such will be a critical element in a comprehensive service training program for techni-
cians.
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, parts catalog and assembly drawings. 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, USE
GROUNDING MAT AND GROUNDING STRAP TO MINIMIZE SHOCK HAZARD,
AND REDUCE CHANCES OF DAMAGE TO SENSITIVE ELECTRONIC COMPO-
NENTS. (6 CMOS IN HANDLE AND 1 CMOS IN PRINTER CHARGER)
Service Manual Components
This manual pn235261 consists of the following components:
236253 Service Manual Text
Assembly Drawings: 236000...011...116...219...220...250
A-Specs: A00848...849, A01745, A01785, A01862
pg 11

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Note: After the first six months of production, the circuit board was improved to the PCB+ circuit board. This
document, however, will explain how to calibrate both the Original PCB and the PCB+. Tell them apart by these
differences: Original PCB has Black and Red calibration wires, blue/white switch PCB+ has a test pin by R24, and
none of the above.
Step 1
USE ESD GROUNDING STRAP AND MAT TO PREVENT DAMAGE TO SENSITIVE COMPONENTS:
REMOVE BATTERY COVER RETAINING SCREW AND REMOVE TWO SCREWS LOCATED UNDER THE
LABEL. BREAK THE ADHESIVE JOINTS. DO NOT PULL THE HOUSINGS COMPLETELY APART SINCE
THE FLEX CIRCUIT AND THE HOSE ARE JOINED AT BOTH HOUSINGS.
PLACE THE MICRO TYMP 1 HANDLE INTO FIXTURE T-5609.
Step 2
PERFORM CURRENT DRAIN TESTS: (taken from A01785 Note #8)
64mAMAXCURRENTDRAINAT+7.2VOLTSUPPLYINFASTBLINKINGOPENMODE,UPTO200mAMAX
WITH PUMP MOTOR AND VENT VALVE ACTUATED.
Step 3
PERFORM FAST CLOCK TESTS:
FOR ORIGINAL PCB, DO THIS: FOR PCB+ BOARD, DO THIS:
FAST CLOCK SHALL BE BETWEEN FAST CLOCK SHALL BE BETWEEN
412-456 (HEX), IF NOT ADJUST C3 412-456 (HEX), IF NOT ADJUST R22
(taken from A-00841,Lev.3,Item 4) (taken from A-01777,Lev.3,Item 5)
(use a trimmer adjustment tool (ignore acceptance criterion on spec.
such as Spectrol 8T000 for C3.) it was developed for manufacturing)
Step 4 (this step has four parts)
PERFORM PROBE TONE LEVEL TEST (sound level):
FOR ORIGINAL PCB, DO THIS: FOR PCB+ BOARD, DO THIS:
Open Sw 1 and apply +3.0 VDC Apply +2.5 VDC to TP2
to TP 2 (Red Wire). (taken from A-01785 Note #4)
(taken from A-00848 Note #4)
1. 1.
If Probe Tone level IS 85 +/-2 dB, If Probe Tone Level IS 84 +/-2 dB,
TURN PAGE, AND DO Orig.PCB Compliance GOTOPAGE14.DOPCB+ComplianceTest.Test.Then
DO Step 5 on page 15. then DO Step 5 on pg 15.
2. 2.
If Probe Tone level IS NOT 85 +/-2dB, If PCB+ Probe Tone IS NOT 84 +/-2dB,
adjust R24 to this value. then adjust R24 to this value.
3. 3.
NOW GO TO TOP OF PAGE 15 and do NOW GO TO MIDDLE OF PAGE 15 and do
Orig. PCB Distortion Test. PCB+ Distortion Test.
4. 4.
NOW GO BACK UP TO PART 1 OF THIS STEP. NOW GO BACK UP TO PART 1 OF THIS STEP.
Reconfirm adjustments made. Reconfirm adjustments made.
pg 12

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Step 4 CONTINUED....
ORIGINAL PCB COMPLIANCE TEST:
(taken from A-00848 SHEET 1 OF 2, ITEM #6,TABLE 1 AND 2.)
(3 VDC STILL CONNECTED) WITH SWITCH 1 OPEN, AND COUPLED TO A 2cc CAVITY, TEST
POINT 3 (BLACK WIRE) SHALL BE SET TO 3.0 VDC +/- .05 BY ADJUSTING R33. SWITCH 1 IS
THEN CLOSED AND THE 3VDC IS DISCONNECTED FROM TP2. OPEN AND CLOSE SWITCH 1
TEN TIMES AND RE-CHECK THE 3V LEVEL AT TP3.
A. USING A 1cc CAVITY ADJUST R70 PER TABLE 1
B. USING A 3cc CAVITY ADJUST R69 PER TABLE 1
C. REPEAT STEPS A AND B UNTIL ACCURATE READINGS ARE OBTAINED
D. USING A 2cc CAVITY COMPLIANCE SHALL BE WITHIN LIMITS AS PER TABLE 2
E. USING A .2cc CAVITY COMPLIANCE SHALL BE WITHIN LIMITS AS PER TABLE 2
ORIGINAL PCB ONLY
BAROMETRIC PRESSURE / COMPLIANCE CALIBRATION POINT
RANGE (Mbar) 3 CC 1 CC
947 - 952 ................... .C5 - C6 ..................... 73 - 74
953 - 959 ....................C4 - C5...................... 72 - 73
960 - 968 ....................C3 - C4...................... 72 - 73
969 - 975 ....................C2 - C3...................... 72 - 73
976 - 983 ....................C1 - C2...................... 71 - 72
984 - 993 ....................C0 - C1...................... 71 - 72
994 -1000 ....................BF - C0...................... 71 - 72
1001 -1008 .................. BE - BF ..................... 70 - 71
1009 -1017 .................. BD - BE ..................... 70 - 71
1018 -1025 .................. BC - BD ..................... 70 - 71
1026 -1031 .................. BB - BC ..................... 6F - 70
ORIGINAL PCB ONLY
TABLE 1 Calibration Points (from A-00848)
ORIGINAL PCB ONLY
BAROMETRIC PRESSURE COMPLIANCE CALIBRATION POINTS
RANGE (Mbar) 3 CC 2 CC 1 CC .2 CC
947 - 952 ..............C4 - CC ......... 9B - 9F .......... 70 - 76 .......... 4A - 52
953 - 959 ..............C3 - CB .........9A - 9F .......... 6F - 75 .......... 49 - 51
960 - 968 ............. C2 - CA ......... 99 - 9E .......... 6F - 75 .......... 49 - 51
969 - 975 ..............C1 - C9.......... 98 - 9D .......... 6F - 75 .......... 49 - 51
976 - 983 ..............C0 - C8.......... 98 - 9D .......... 6E - 74 .......... 49 - 51
984 - 993 ..............BF - C7.......... 97 - 9C .......... 6E - 74 .......... 49 - 51
994 -1000 ..............BE - C6.......... 96 - 9B .......... 6E - 74 .......... 49 - 51
1001 -1008 ............ BD - C5 ......... 96 - 9B .......... 6D - 73 .......... 49 - 51
1009 -1017 .............BC - C4 ......... 95 - 9A ......... .6D - 73 ......... 49 - 51
1018 -1020 .............BB - C3 ......... 95 - 9A .......... 6D - 73 .......... 49 - 51
1021 -1025 .............BB - C3 ......... 94 - 99 .......... 6D - 73 .......... 49 - 51
1026 -1031 ............ BA - C2 ......... 94 - 99 .......... 6C - 72 .......... 49 - 51
ORIGINAL PCB ONLY
TABLE 2 Calibration Points (from A-00848 sheet 1 of 2)
GO TO STEP 5 pg 13

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Step 4 CONTINUED....
PCB+COMPLIANCETEST:
(taken from A-01785, Note 6 referring to Tables 1 and 2 of Fig.2)
COUPLE A 2cc CAVITY WITH NO CONNECTION TO TEST POINT 2. THE OUTPUT AT TEST POINT
TP-2 SHALL BE 2.50 VDC +/- .05 VDC, IF NOT ADJUST R33.
A. USING A 3cc CAVITY ADJUST R69 AS PER TABLE 1 BELOW.
B. USING A .5cc CAVITY ADJUST R70 AS PER TABLE 1 BELOW.
C. REPEAT A AND B UNTIL READINGS ARE CORRECT.
D. USING A 2cc CAVITY COMPLIANCE SHALL BE WITHIN LIMITS PER TABLE 2 BELOW.
E. USING A 1.0cc CAVITY COMPLIANCE SHALL BE WITHIN LIMITS PER TABLE 2 BELOW.
F. USING A .2cc CAVITY COMPLIANCE SHALL BE WITHIN LIMITS PER TABLE 2 BELOW.
PCB+ ONLY
BAROMETRIC PRESSURE / COMPLIANCE CALIBRATION POINT
RANGE ( Mbar) 3 CC .5 CC
947 - 952 ................... C8 - C9 ....................... 5D - 5E
953 - 959 ................... C7 - C8 ....................... 5D - 5E
960 - 968 ................... C6 - C7 ....................... 5C - 5D
969 - 975 ................... C5 - C6 ....................... 5C - 5D
976 - 983 ................... C4 - C5 ....................... 5C - 5D
984 - 993 ................... C3 - C4 ....................... 5C - 5D
994 -1000 ................... C2 - C3 ....................... 5C - 5D
1001 -1008 .................. C1 - C2 ....................... 5C - 5D
1009 -1017 .................. C0 - C1 ....................... 5C - 5D
1018 -1020 .................. BF - C0 ....................... 5C - 5D
1021 -1025 .................. BF - C0 ....................... 5C - 5D
1026 -1031 .................. BE - BF....................... 5C - 5D
‘PCB+’ ONLY
TABLE 1 “PCB+ NOMINAL SET POINTS”(from A-01785, Fig. 2)
‘PCB+’ ONLY
BAROMETRIC PRESSURE COMPLIANCE CALIBRATION POINTS
RANGE ( Mbar) 3 CC 2 CC 1 CC .5 CC .2 CC
947 - 952 ........C5 - CB .........9C - A0.......... 70 - 76 .......... 5B - 60 .......... 4F - 53
953 - 959.........C4 - CA ......... 9B - 9F .......... 6F - 75 .......... 5B - 60 .......... 4E - 52
960 - 968 ........C3 - C9..........9A - 9E.......... 6F - 75 ..........5A - 5F.......... 4E - 52
969 - 975 ........C2 - C8.......... 99 - 9D .......... 6F - 75 ..........5A - 5F.......... 4E - 52
976 - 983 ........C1 - C7.......... 99 - 9D .......... 6E - 74 ..........5A - 5F .......... 4E - 52
984 - 993 ........C0 - C6.......... 98 - 9C .......... 6E - 74 .......... 5A - 5F .......... 4E - 52
994 -1000 ........BF - C5.......... 97 - 9B .......... 6E - 74 .......... 5A - 5F .......... 4E - 52
1001 -1008 .......BE - C4.......... 97 - 9B .......... 6D - 73 .......... 5A - 5F .......... 4E - 52
1009 -1017 ...... BD - C3 ......... 96 - 9A .......... 6D - 73 ..........5A - 5F .......... 4E - 52
1018 -1020 .......BC - C2 ......... 96 - 9A .......... 6D - 73 .......... 5A - 5F.......... 4E - 52
1021 -1025 .......BC - C2 ......... 95 - 99 .......... 6D - 73 ......... .5A - 5F ......... 4E - 52
1026 -1031 .......BB - C1 ......... 95 - 99 .......... 6C - 72 ......... .5A - 5F ......... 4E - 52
‘PCB+’ ONLY
TABLE 2 “PCB+ ALLOWABLE RANGE”(from A-O1785, Fig. 2)
GO TO STEP 5 pg 14

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Step 4 CONTINUED....
ORIGINAL PCB DISTORTION TEST:
SET UP:AS PER SOUND LEVEL TEST, EXCEPT FOR THE CENTER FREQUENCY OF THE FILTER.
THE MEASURED LEVELS SHALL NOT EXCEED THOSE SHOWN BELOW:
FILTER CENTER FREQ. (Hz) MAXIMUM SOUND LEVEL (dB)
500 ...................................................... 55
1000 ...................................................... 49
2000 ...................................................... 39
ORIG PCB DISTORTION TEST LEVELS (from A-00848,sheet 1 of 2, note 5)
PCB+ DISTORTION TEST:
THE MEASURED LEVELS SHALL NOT EXCEED THOSE SHOWN IN AT LEAST ONE OF THE THREE
MAXIMUM SOUND LEVEL COLUMNS BELOW.
NOTE: WHEN YOU START THE TEST AT 500 Hz AND MEASURE A SOUND LEVEL IN ONE OF THE
COLUMNS BELOW, R E M A I N IN THAT PARTICULAR COLUMN FOR READINGS AT 630 Hz
AND 1000 Hz. DO NOT SWITCH TO ANOTHER COLUMN.
1/3 OCTAVE FILTER MAXIMUM SOUND LEVEL (dB)
CENTER FREQ. (Hz)
500 ...................................................39.3................ 45.0 ............... 47.6
630 ...................................................56.0................ 54.3 ............... 51.3
1000 ...................................................38.3................ 40.0 ............... 45.5
PCB+ DISTORTION TEST (from A-01785, table 5)
...........................................................................
NOTE: After this point, the tests for Original PCB and PCB+ are identical.
Step 5
PERFORM PNEUMATIC SEAL PRESSURE TEST
(taken from A-01785 note#3. Good for both Original PCB and PCB+)
CONNECT UNIT TO A MANOMETER. WITH THE CALIBRATOR IN THE CALIBRATE MODE,
DEPRESS “UP” BUTTON TO LATCH THE VALVE IN CLOSED POSITION. AT PRESSURES OF
+300 dapa AND -300 daPa, THE LEAK RATE SHALL BE LESS THAN 12 daPa OVER A 5 SEC-
OND PERIOD. TO RESET THE VALVE, FLIP THE CALIBRATE/RUN SWITCH TO THE RUN
POSITION FOR APPROXIMATELY ONE SECOND. THEN FLIP THE SWITCH BACK TO THE
CALIBRATE POSITION.
pg 15

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Step 6
PERFORM PRESSURE CALIBRATION TEST:(taken from A-00849, pg.1,item 6, F&G)
A) CONNECT UNIT TO MANOMETER OR EXTERNAL PRESSURE SOURCE AT ‘0’ daPa. AT 0 daPA,
IF READING IS AT OR BETWEEN 89 -8B (HEX), DO STEP B. IF THE READING IS NOT AT OR
BETWEEN 89 - 8B HEX AT 0 daPa, THEN ADJUST R26 TO OR WITHIN
THESEVALUES.
B) PRESSURIZE UNIT TO +200 daPa. IF READING IS AT OR BETWEEN B1 - B3 (HEX), THEN
DO STEP C. IF READING IS NOT AT OR BETWEEN B1 - B3 AT +200 daPa, (HEX), THEN AD-
JUST R31 TO AT OR WITHIN THESE VALUES. REPEAT FIRST TWO STEPS A & B UNTIL
YOU ARRIVE AT THESE VALUES THEN GO TO STEP C.
C) PRESSURIZE TO -300 daPa. IF READING IS AT OR BETWEEN 49 - 53 (HEX), THEN GO TO
STEP #7.
CAUTION: DO NOT MAKE ADJUSTMENTS SOLELY ON THE BASIS OF THE -300 daPa READING. Doing
so will un-do prior adjustments. If the reading IS NOT at or between 49-53 (HEX), DO NOT ADJUST
THE POTS AT -300 DdaPa. DO A OR B BELOW:
A ........ IF THE READING IS ABOVE 53 HEX: (readings will be high if the ‘span’ is too narrow.) TURN R31
CLOCKWISE TO INCREASE the ‘span’ between 0 and +200 daPa IMPORTANT: RE-CHECK at 0
and +200 daPa to verify that unit is within spec.
B ........ IF THE READING IS BELOW 49 HEX: (readings will be low if the ‘span’ is too wide.) TURN R31
COUNTER CLOCKWISE TO DECREASE the ‘span’ between 0 and +20 daPa. IMPORTANT: RE-
CHECK AT 0 and +200 daPa to verify that unit is within specifications.
Step 7
VENT RATE TEST:
MAKE SURE THE MICROTYMP 1 IS IN THE ‘CALIBRATION’ MODE AND IS PRESSURIZED
TO +250 daPa. NOW ENTER THE ‘RUN’ MODE TO VENT THE SYSTEM AND TIME THE
PRESSURE DROP. THE PRESSURE MUST DROP TO 0 daPa WITHIN 1 SECOND.
Step 8
SWEEP RATE TEST: See Figure Step 8 below.
WITH THE PROBE TIP COUPLED TO A 1cc CAVITY, THE SWEEP RATE SHALL BE SET AT
OR BETWEEN 2.40 - 2.55 SECONDS BY ADJUSTING R39. MEASURE FROM LEADING EDGE
OF FIRST PULSE TO LEADING EDGE OF 26TH PULSE (which is 2.40-2.55 sec.)
Figure Step 8 “PUMP SPEED” (from A-01785, Fig.1). pg 16
O
O
PUMP SPEED
OPEN PRESSURIZATION
PERION
SWEEP
PERIOD
+5V.D.C.
+5V.D.C.
ACTUATED
VOLTAGE
ATTPB
START/RUN
BUTTON
VOLTAGE
ATTPBA
VOLTAGE
ATTP7
26

Section 2.4 Service MT 1 CALIBRATION PROCEDURE
Step 9
PUMP PRESSURIZATION TEST:
WITH THE TIP COUPLED TO A 1cc CAVITY, AND THE START/RUN BUTTON ACTIVATED, THE
PRESSURIZATION PERIOD SHALL BE .5 - 1 SECOND. See Fig.”Step8" page 16.
Step 10
PUMP SPEED AND LINEARITY TEST: (EVEN THOUGH STEP 8 AND 9 REQUIREMENTS MAY BE
MET, DO NOT SKIP THIS STEP 10. THE REASON IS THAT THE PUMP MAY NOT BE
ABLE TO PERFORM A TYMP WITH A 2 CC CAVITY EVEN THOUGH IT PASSED WITH THE
SMALLER CAVITIES IN STEPS 8 AND 9. THE UNIT MUST BE ABLE TO RUN A COMPLETE AND
ACCURATE TEST ON CAVITY SIZES UP TO 1.9cc. TEST WITH A 2CC CAVITY. MEASURE THE
PULSES AT TEST POINT 7, DURING THE SWEEP PERIOD. SPECS ARE BETWEEN 50 - 150 Ms.
Step 11
PUMP NOISE TEST:
WITH THE UNIT COUPLED TO A .5cc CAVITY, PRESS THE START/RUN BUTTON. THE RESULT-
ING FLAT LINE OF THE TEST SHALL NOT DEVIATE BY MORE THAN 1 PIXEL.
Step 12
OPEN DETECT TEST:
WITH TIP OPEN TO THE ATMOSPHERE, DEPRESS THE START/RUN BUTTON MOMENTARILY.
THE OPEN SYMBOL (on handle label) SHALL FLASH REPEATEDLY ON THE LCD.
Step 13
BLOCK DETECT TEST:
WITH THE PROBE TIP OCCLUDED, PRESS THE START/RUN BUTTON. THE UNIT SHALL DIS-
PLAY THE BLOCK SYMBOL (on handle label) ALTERNATING WITH THE RUN SYMBOL ON THE
LCD.
Step 14
LEAK DETECT TEST:
RUN THE UNIT IN A 1cc to 2.cc TEST CAVITY. WITH THE UNIT UNDER A POSITIVE PRESSURE,
(BETWEEN +200 AND 0 daPa), PULL THE CAVITY AWAY FROM THE UNIT. THE RUN AND LEAK
INDICATORS, (shown on the handle label) SHALL APPEAR ON THE LCD.
Step 15
MEMORY RECALL TEST:
RUN AN EAR SIMULATOR TEST FOR THE RIGHT MEMORY AND STORE IT, THEN RUN ONE FOR
THE LEFT EAR AND STORE IT. ALLOW THE UNIT TO TIME OUT (APPROX 40 SECONDS FOR
AUTO-OFF). RESTART THE UNIT AND VERIFY THAT BOTH TESTS ARE STILL THERE AND
ACCURATE.
Step 17
ERASE TIME TEST:
PUSH ‘LEFT EAR’ BUTTON. ‘BLANK’ MEMORY SYMBOL WILL DISPLAY FOR 2.7 - 3.3 SECONDS.
THIS TIME MAY BE MEASURED BY THE INTERVAL BETWEEN THE CORRESPONDING PULSES
AT TEST POINT 7. ADJUST R21 TO ACHIEVE THIS SPECIFICATION.
pg 17