Welch Allyn Micro Tymp 2 User manual

4341 State Street Road
P.O.Box 220
Skaneateles Falls, NY 13153-0220
Copyright 1995
MicroTymp 2
Tympanometric System
23640 handle, 71170 printer charger
(Includes CE Model)
Service Manual
Part #:236409

Part Rev Desc. of Change ECN # Date Initiator
236409 B New Release 5-28225 6/95 R. Settembre
236409 C Added CE Updates & Cautions 5-35489 6/97 R. Settembre
NOTE: Drawings & illustrations in this document are for reference only. Consult system
or call factory for latest revisions.
MICROTYMP 2

SERVICE MANUAL
MicroTymp 2
Tympanometric System
23640 handle, 71170 printer charger
(Includes CE Model)
Copyright 1995
Welch Allyn Co.
4341 State Street Road Welch Allyn
P.O. Box 220
Skaneateles Falls, NY 13153-0220 Service Manual Part #:236409

FORWARD
This manual provides technical assistance for calibrating, diagnosing, and servic-
ing the Welch Allyn MICROTYMP 2 handle and Printer/Charger.
The MicroTymp 2 and or Printer Charger will be returned to the Technical Ser-
vice Department for either Recalibration (handle only) or for diagnosis and repair. For
Printer Charger tests, refer to current factory approved diagnostic tests. Once the fault
has been determined, refer to the Manual chapters I and J for the appropriate Removal
and Replacement sequence. Re-test the Printer Charger after the repair is completed.
Similarly, when servicing the MicroTymp 2 handle, refer to the most recent troubleshoot-
ing guide and Calvin Users guide. Once the failed component has been identified, refer
to the Manual chapters B through H for the appropriate Removal and Replacement
sequence. Re-test (re-calibrate) the handle once the repair has been completed.
The repair ‘TASK’ procedures (R & R .. Removal and Replacement) are written
to provide quick and easy reference for different experience levels of repair technician.
Required specifications and materials are listed at each step where applicable. For
example:
Instructions will start off with a “TASK, TO DO.” For example, B. 3. “Unplug Flex
Circuit” statement. This will be followed by a “TECHNIQUE, HOW TO DO” statement.
Follow these steps to preform the task.— “Grasp pump assembly flex circuit with pin
straightening pliers.”
This manual is written in a style useful for training and or translation. Set up
training sessions to allow the trainee to practice the use of the diagnostic, repair, adjust-
ment, and re-testing procedures found in this manual. Set up hands-on practice ses-
sions to enable the technician to develop and retain skills. Provide each trainee with the
opportunity to practice the procedure(s) after it has been demonstrated by the instructor.
I M P O R T A N T :
Welch Allyn service part numbers and material numbers appearing in this manual are
for the purpose of familiarizing new technicians with the Welch Allyn parts numbering
system. Order replacement parts, as always, 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.
i

*** SAFE SERVICE ***
CLEAN AND DISINFECT per instructions in MicroTymp2 Operating Instructions PN
236311 PAGE C-50 prior to repairing, or calibrating all returned MicroTymp 2’s.
PERFORM appropriate “A” tests after servicing to assure safe, accurate and reliable
product operation.
*** QUALITY SERVICE ***
WEAR an ESD wrist strap when servicing the MicroTymp 2 or handling printed circuit
boards.
STORE new and used boards in anti-static bags.
UPDATE your Repair & Training Manual by notating changes and revisions of part
numbers and procedures.
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 sus-
pected, PROCEED NO FURTHER ! DO NOT disassemble, repair, adjust, or in any way
alter the MicroTymp 2 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 2 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.
ii

TABLE OF CONTENTS / MICRO TYMP 2
Forward - - - - - - - - - i
Safe Service - - - - - - - - - ii
Section 1
Removal and replacement ( r & r ):
A Normal maintenance - - - - - - - - - 1
B Power supply board assembly - - - - - - - - - 2
C Motor/pump assembly - - - - - - - - - 3
D MCU Board assembly - - - - - - - - - 3 - 4
E Keypad assembly - - - - - - - - - 4 - 5
F LCD Assembly - - - - - - - - - 5
G ESD Shields - - - - - - - - - 6
H Valve - - - - - - - - - 7
I Ballast - - - - - - - - - 7
J Printer / charger keypad - - - - - - - - - 8
K Printer and or PCB - - - - - - - - - 8 - 10
Section 2 Preliminary Handle Bench Test
Section 3 Micro Tymp 2 Noise Test Procedure
Section 4 Technical Troubleshooting Guide for Micro Tymp 2 Handles & Printer Chargers
Section 5 Customer Service Questions/Answers
Section 6 CALVIN, Micro Tymp 2 Calibration System User Manual
Section 7 Micro Tymp 2 NEEDS CAL Error Troubleshooting Guide
Section 8 Tools/Test Equipment listing Calvin Components
Section 9 Repair Parts
Section 10 Drawings
Section 11 A-02727 Process Sheet excerpts for 23641 Micro Tymp 2 Handle tests
Section 12 A-02728 Process Sheet excerpts for 71171, 71172, 71174, 71176, 71179
Micro Tymp 2 Printer Charger Tests

ANORMAL MAINTENANCE : BATTERY COVER, BATTERY, RECHARGING
BATTERY, RECYCLING THE USED BATTERY
A 1. REFER TO PAGE C-43 THROUGH C-47 OF MICROTYMP 2 OPERATING
INSTRUCTIONS FOR REPLACEMENT OF BATTERY PN72900.
WARNING: INSERT BATTERY ONLY AS SHOWN IN THE OWNERS
MANUAL. FAILURE TO OBSERVE CORRECT POLARITY COULD CAUSE
DAMAGE TO THE MICRO TYMP 2. WHEN IT IS NECESSARY TO RE-
PLACE THE BATTERY, USE ONLY A WELCH ALLYN PN72900 REPLACE-
MENT BATTERY. OTHER NON APPROVED BATTERIES MAY CAUSE
RISK OF FIRE OR PRODUCT FAILURE.
CAUTION:The battery must be removed if the MicroTymp 2 is to be stored
or placed anywhere other than in the Charging Stand (or connected to the
Charging Transformer) for more than one month.Failure to do this can
result in damage to BOTH the battery and the MicroTymp 2.
A 2. FOLLOW THIS PROCEDURE FOR DECIDING WHEN TO REPLACE THE NI-
CAD BATTERY IN A MICRO TYMP HANDLE: (AS ALWAYS, READ THE
CUSTOMER COMPLAINT FIRST.)
SCENARIO 1 If the unit FUNCTIONS, (the battery has held sufficient charge during
approximately two days transit) the battery meets requirements. No
corrective action is to be taken. However, it is good practice to put the
battery on charge for however long it is in your possession.
OR
SCENARIO 2 a If the unit DOES NOT FUNCTION AND the battery is IN warranty, put in
a fully charged new battery (your test battery). If the unit functions, and
Low Battery symbol disappears, REPLACE THE BATTERY UNDER
WARRANTY. Install a fully charged BATTERY. Recycle the failed battery
per Welch Allyn’s recycling policy.
2 b If the unit DOES NOT FUNCTION AND the battery is OUT of warranty,
put in a fully charged new battery (your test battery). If the unit functions,
sell a new battery. If the unit does not function, look for other problems
while charging the customer’s battery. Sell a new battery if customer’s
battery won’t ACCEPT AND HOLD a full charge.
NOTES:
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
1

NOTE: WEAR ESD WRIST STRAP WHILE PERFORMING THE FOLLOWING OPERATIONS.
BPOWER SUPPLY BOARD ( TOP BOARD ) ASSEMBLY
B1.REMOVE BATTERY COVER.
FOLLOW INSTRUCTIONS IN MICROTYMP 2 OPERATING INSTRUCTIONS
TO REMOVE BATTERY COVER AND BATTERY. IT IS NOT NECESSARY
TO REMOVE THE FRONT HOUSING ASSEMBLY FOR POWER SUPPLY
BOARD REPLACEMENT.
B2.DISCONNECT TUBING FROM TOP BOARD.
REMOVE TUBING FROM MOTOR/PUMP ASSEMBLY.
REMOVE TUBE FROM BALLAST.
B3.UNPLUG FLEX CIRCUIT.
GRASP PUMP ASSEMBLY FLEX CIRCUIT WITH PIN STRAIGHTENING
PLIERS. PULL STRAIGHT UP TO REMOVE FLEX CIRCUIT FROM THE
POWER SUPPLY BOARD.
B4.REMOVE POWER SUPPLY BOARD.
UNSCREW 4 PHILLIPS HEAD SCREWS AT THE FOUR CORNERS OF `
THE POWER SUPPLY BOARD. LIFT THE CONTACTS FROM THE CASE
AND LIFT POWER SUPPLY BOARD STRAIGHT UP.
REPLACE POWER SUPPLY BOARD
B4.REPLACE POWER SUPPLY BOARD.
ATTACH TUBING TO THE PUMP AND THE BALLAST. REFER TO TUBING
ROUTING DIAGRAM ON DRAWING 236300. ALIGN BOARD OVER STAND-
OFFS WITH BATTERY HOLDER NEAR THE BOTTOM OF THE HANDLE.
SCREW THE BOARD TO THE STRAIN RELIEFS WITH TWO LONG
SCREWS AT THE BOTTOM OF THE BOARD, AND TWO SHORT SCREWS
AT THE TOP OF THE BOARD.
B5.PLUG IN FLEX CIRCUIT.
PLUG FLEX CIRCUIT INTO BOARD USING PIN STRAIGHTENING PLIERS
OR FINGERS. IF THE TWO FIBER SEPARATORS BECOME LOOSE, RE-
CONNECT THEM IN THEIR ORIGINAL POSITION (REFER TO ASSEMBLY
DRAWING) WITH LOCTITE BLACK MAX ADHESIVE M-30341.
B6.CALIBRATE HANDLE WITH CALVIN.
REFER TO SECTION 6 FOR CALVIN PROCEDURE. UPON SUCCESS-
FUL CALIBRATION AND TEST, PLACE A DROP OF BLACK MAX tm
ADHESIVE M-30341 BETWEEN THE FRONT HOUSING AND THE FIBER
STRIPS. REPLACE BATTERY AND BATTERY COVER.
SCREW BATTERY COVER IN PLACE.
END POWER SUPPLY BOARD REPLACEMENT
NOTES:________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
2

CMOTOR/PUMP ASSEMBLY
C1.REMOVE BATTERY COVER AND BATTERY.
UNSCREW BATTERY COVER SCREW AND REMOVE THE COVER.
REMOVE THE BATTERY FROM THE BATTERY HOLDER.
C2.REMOVE FRONT HOUSING ASSEMBLY.
PEEL THE WELCH ALLYN LABEL FROM THE UNIT AND UNSCREW TWO
SCREWS UNDER THE LABEL. REMOVE THE FRONT HOUSING ASSEMBLY
FROM THE HANDLE. DO NOT UNPLUG FLEX CIRCUIT FROM LCD BOARD.
NOTE: If unit is a CE model, take caution in removing the front housing.
There are two pieces of fragile ESD tape at both corners.
C3.REMOVE TUBING FROM MOTOR/PUMP ASSEMBLY.
PULL TUBE FROM THE PUMP. PULL TUBE FROM THE BALLAST.
DISCONNECT FLEX CIRCUIT FROM SWITCHES BOARD AND POWER
SUPPLY BOARD. GENTLY LIFT MOTOR/PUMP ASSEMBLY UP.
REPLACE MOTOR PUMP ASSEMBLY
C4.REPLACE MOTOR/PUMP ASSEMBLY.
INSTALL REPLACEMENT PRE/ADJUSTED MOTOR/PUMP ASSEMBLY
OVER LCD RETAINER. RE-ATTACH FLEX CIRCUITS TO POWER BOARD
AND SWITCH BOARD. USE PIN STRAIGHTENING PLIERS OR FINGERS
TO RE-ATTACH FLEX CIRCUITS. RE ATTACH FRONT HOUSING ASSEM-
BLY. LAY FLEX CIRCUITS IN ACCORDING TO DRAWING #236300.
C5.CALIBRATE HANDLE WITH CALVIN.
REFER TO SECTION 6 FOR CALVIN PROCEDURE. UPON SUCCESSFUL
CALIBRATION AND TEST, PLACE A DROP OF BLACK MAX tm ADHESIVE
M-30341 BETWEEN THE FRONT HOUSING AND THE FIBER STRIPS.
REPLACE BATTERY AND BATTERY COVER. SCREW BATTERY COVER
IN PLACE.
NOTES:________________________________________________________________________
______________________________________________________________________________
DMCU ( BOTTOM ) BOARD
D1.REMOVE POWER SUPPLY BOARD ( TOP BOARD ).
FOLLOW INSTRUCTIONS IN SECTION B FOR REMOVAL OF POWER
SUPPLY BOARD.
D2.UNPLUG FLEX CIRCUIT FROM MCU BOARD ( BOTTOM BOARD ).
USE PIN STRAIGHTENING PLIERS OR FINGERS TO GENTLY PULL THE
FLEX CIRCUIT FROM THE MCU BOARD SOCKET.
D3.REMOVE MCU BOARD.
UNSCREW FOUR STANDOFFS WITH 1/8" NUT DRIVER. GENTLY PULL
THE BOARD STRAIGHT OUT OF THE HOUSING. FOUR PLASTIC
SPACERS ARE ATTACHED TO THE BOARD AT EACH SCREW HOLE.
TRANSFER THESE TO THE REPLACEMENT MCU BOARD.
3

DMCU ( BOTTOM ) BOARD
D4.REPLACE MCU BOARD.
INSTALL FOUR PLASTIC SPACERS ON THE BOTTOM OF THE BOARD.
INSERT REPLACEMENT BOARD INTO HANDLE WITH INFRA-RED LED AT
BASE OF HANDLE FACING IR WINDOW. SCREW FOUR STANDOFFS
INTO CORNERS OF MCU BOARD. TIGHTEN TO 1.5 TO 2 INCH LBS.
D5.PLUG IN FLEX CIRCUIT.
CONNECT THE FLEX CIRCUIT TO THE MCU BOARD SOCKET. INSERT
SIDE CONTACTS INTO THE SLOTS OF THE BACK HOUSING WITH THE
BLACK WIRE ON THE RIGHT (BALLAST) SIDE, AND THE RED WIRE ON
THE LEFT SIDE. TUCK CONTACT WIRES UP AGAINST BOTTOM END OF
BATTERY RETAINER.
D6.INSTALL POWER SUPPLY BOARD.
FOLLOW INSTRUCTIONS IN SECTION B FOR REPLACEMENT OF
POWER SUPPLY BOARD. CALIBRATE UNIT USING CALVIN SYSTEM
(CALVIN USERS MANUAL IN SECTION 6)
NOTES:________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
EKEYPAD ASSEMBLY
E1.REMOVE FRONT HOUSING ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION C2 TO REMOVE FRONT HOUS-
ING.
E2.REMOVE MOTOR/PUMP ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION C3 TO REMOVE MOTOR/PUMP
ASSEMBLY.
E3.REMOVE LCD MODULE SUPPORT FROM BACK HOUSING.
UNSCREW TWO SCREWS AND LIFT SUPPORT DOWN AND AWAY FROM
LCD MODULE. DO NOT ALLOW THE LCD DISPLAY TO FALL OUT OF
THE BACK HOUSING. PRESS ANY BUTTON TO LIFT KEYPAD ASSEM-
BLY OUT OF BACK HOUSING.
REPLACE KEYPAD ASSEMBLY
E4.REPLACE KEYPAD ASSEMBLY.
INSERT REPLACEMENT KEYPAD ASSEMBLY INTO HOLES IN BACK
HOUSING WITH LETTERS RIGHT SIDE ‘UP’. ALIGN LCD RETAINER
OVER LCD AND KEYPAD ASSEMBLY AND INSERT LATCH OF RETAINER
INTO NOTCH IN TOP OF BACK HOUSING. ALIGN 2 ALIGNMENT PINS ON
THE BACK OF THE RETAINER WITH THE TWO ALIGNMENT HOLES IN
THE KEYPAD ASSEMBLY PRINTED CIRCUIT BOARD. SECURE RE-
TAINER WITH TWO SCREWS.4

EKEYPAD ASSEMBLY
E5.REPLACE MOTOR/PUMP ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION C4 THROUGH C6 FOR MOTOR/
PUMP ASSEMBLY.
E6.TEST HANDLE.
PERFORM FUNCTIONAL CHECKS TO ASSURE CORRECT OPERATION
OF REPLACEMENT SWITCHES.
NOTES:________________________________________________________________________
______________________________________________________________________________
FLCD ASSEMBLY
F1.REMOVE LCD RETAINER.
FOLLOW STEPS E1 THROUGH E3 TO REMOVE LCD RETAINER.
F2.REMOVE LCD MODULE.
LIFT OUT LCD MODULE.
REPLACE LCD ASSEMBLY
F3.PLACE LCD ASSEMBLY INTO BACK HOUSING.
REMOVE PROTECTIVE FILM FROM BEZEL. RECORD LCD ID# ON DOCU-
MENTATION. ALIGN LCD ASSEMBLY WITH FLEX CIRCUIT CONNECTOR
ON RIGHT HAND SIDE THEN PLACE INTO HOUSING.
F4.SECURE MODULE WITH RETAINER.
PLACE LCD MODULE RETAINER AND PLACE LATCH IN THE NOTCH AT
THE TOP OF THE BACK HOUSING. ALIGN TWO PINS ON UNDERSIDE
OF RETAINER WITH TWO ALIGNMENT HOLES OF KEYPAD PCB.
SECURE WITH TWO SCREWS.
F5.REASSEMBLE HANDLE.
FOLLOW INSTRUCTIONS IN SECTION C 4 THROUGH C 6 AND
PERFORM FUNCTIONAL CHECKS.
END LCD ASSEMBLY REPLACEMENT
NOTES:________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
5

GESD SHIELDS (CE MODEL)
REMOVAL OF ESD SHIELDS (SEE FIG. G-1)
G1.REMOVE POWER SUPPLY BOARD.
FOLLOW INSTRUCTIONS IN SECTION B.
G2.REMOVE MOTOR PUMP ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION C.
G3.REMOVE MCU BOARD.
FOLLOW INSTRUCTIONS IN SECTION D.
G4.REMOVE KEYPAD ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION E.
G5.REMOVE LCD ASSEMBLY.
FOLLOW INSTRUCTIONS IN SECTION F.
G6.REMOVE ESD SHIELDS.
THE LCD GASKET AND THE ESD SHIELD ARE CONNECTED WITH TWO
STRIPS OF ESD TAPE. THESE ASSEMBLED SHIELDS SHOULD PULL
OUT OF THE BOTTOM HOUSING.
NOTES:________________________________________________________________________
_____________________________________________________________________
REPLACEMENT OF ESD SHIELDS (CE MODEL)
G 17. REPLACE SHIELDS AS PER ASPEC A02727.
G 17. REASSEMBLE UNIT.
FOLLOW STEPS G1 THROUGH G6 IN REVERSE ORDER.
FIG. G-1 HANDLE CE LABEL
6

HVALVE
H1.REMOVE VALVE FROM POWER SUPPLY BOARD.
REMOVE BATTERY COVER AND BATTERY FROM HANDLE. REMOVE
POWER SUPPLY BOARD FROM HANDLE BY FOLLOWING STEPS IN
SECTION B 1 THROUGH B 4. UN-SOLDER VALVE FROM FOUR CON-
NECTION POINTS UNDER THE POWER SUPPLY BOARD. LIFT VALVE
FROM BOARD AND DISCONNECT TUBING FROM VALVE.
REPLACE VALVE
H2.INSTALL REPLACEMENT VALVE.
ATTACH TUBING TO PRE-TESTED, PRE-TRIMMED REPLACEMENT
VALVE. PREPARE BOARD FOR RE-SOLDERING BY REMOVING EXCESS
SOLDER AND CLEARING BOARD HOLES TO ACCEPT REPLACEMENT
VALVE. INSERT REPLACEMENT VALVE IN PLACE WITH THE TUBE-END
TOWARDS THE BALLAST. SOLDER THE VALVE IN PLACE. CLIP OFF
VALVE LEADS ABOVE SOLDER JOINTS.
H3.INSTALL POWER SUPPLY BOARD INTO HANDLE.
FOLLOW STEPS B 4 THROUGH B 5 TO INSTALL POWER SUPPLY BOARD.
H4.CALIBRATE HANDLE.
FOLLOW CALVIN PROCEDURE TO CALIBRATE HANDLE.
END VALVE REPLACEMENT
NOTES:________________________________________________________________________
IBALLAST
I1.REMOVE BALLAST FROM POWER SUPPLY BOARD.
REMOVE BATTERY COVER AND BATTERY FROM HANDLE. GENTLY
PULL BALLAST FROM THE POWER SUPPLY BOARD. LIFT BALLAST
FROM BOARD AND DISCONNECT TUBING FROM BALLAST. REMOVE
DOUBLE SIDED TAPE FROM BOARD IF IT IS PARTIALLY TORN AWAY.
REPLACE BALLAST
I2.INSTALL REPLACEMENT BALLAST.
CLEAN BOTTOM OF BALLAST WITH ALCOHOL AND LET DRY ONE
MINUTE. ATTACH TUBING TO REPLACEMENT BALLAST BY FIRST
ATTACHING TUBING FROM THE PROBE TIP TO THE TOP END OF THE
BALLAST. THEN ATTACH TUBING FROM THE VALVE TO THE TOP SIDE-
PORT OF THE BALLAST. ATTACH TUBING FROM THE PUMP TOP CAP
TO THE LOWER SIDE PORT OF THE BALLAST. CLEAN MOUNTING
SURFACE FOR REPLACEMENT DOUBLE SIDED FOAM TAPE. APPLY
BROWN LAYER SIDE OF 2 SIDED TAPE TO BOTTOM OF BALLAST.
ATTACH ADHESIVE BACKED WARNING LABEL TO SIDE OF BALLAST.
CHECK ALL TUBING FOR SHARP BENDS, TWISTS OR LEAKS.
I3.CALIBRATE HANDLE.
FOLLOW CALVIN PROCEDURE TO CALIBRATE HANDLE.
END BALLAST REPLACEMENT
7

JKEYPAD
J1.REMOVE KEYPAD.
UNPLUG MICROTYMP 2 PRINTER/CHARGER FROM LINE VOLTAGE.
PEEL OLD KEYPAD FROM PRINTER/CHARGER TOP PANEL USING
FINGERNAIL UNDER ONE CORNER.
J2.UNPLUG FLEX CIRCUIT.
GENTLY PULL FLEX CIRCUIT FROM BACK OF KEYPAD. REMOVE ANY
RESIDUAL ADHESIVE FROM THE PRINTER/CHARGER TOP PANEL WITH
ALCOHOL. WAIT ONE MINUTE FOR ALCOHOL TO EVAPORATE.
REPLACE KEYPAD
J3.INSTALL REPLACEMENT KEYPAD.
REMOVE ADHESIVE LINER FROM PCB. PLUG FLEX CIRCUIT INTO
KEYPAD PCB. DO NOT TWIST FLEX CIRCUIT. POSITION KEYPAD BOT-
TOM EDGE WITH THE BOTTOM EDGE OF THE KEYPAD RECESS IN THE
TOP PANEL. POSITION TWO SEMI-CIRCULAR DETENTES IN THE KEY-
PAD RECESS FIT INTO TWO SEMI-CIRCULAR CUTOUTS ON THE KEY-
PAD PCB. FEED THE FLEX CIRCUIT INTO THE HOLE OF THE TOP
PANEL AS YOU PLACE THE KEYPAD AGAINST THE TOP PANEL.
J4.TEST PRINTER/CHARGER.
PERFORM FULL FUNCTIONAL TESTS ON PRINTER/CHARGER. REFER
TO SPECIFICATION A-02728 IN SECTION 12.
END PRINTER/CHARGER KEYPAD REPLACEMENT
NOTES:________________________________________________________________________
______________________________________________________________________________
KPRINTER AND/OR PCB
NOTE: A CE MODEL PRINTER
(SEE LABEL) WILL CONTAIN MAIN PCB #711730-509. DO NOT REPLACE
IT WITH A 711730-508 (NON CE BOARD). YOU CAN NOT UPGRADE A 508
BOARD TO A 509 BOARD. YOU CAN PUT A 509 INTO A UNIT IN PLACE
OF A 508.
K1.REMOVE PAPER.
REMOVE PAPER ACCESS COVER BY PULLING UP ON THE FRONT
EDGE. PULL PAPER LEVER AND REMOVE PAPER ROLL AND SPINDLE.
K2.REMOVE TOP PANEL FROM CASE.
REFER TO FIG. I-1 IN THIS MANUAL. DO NOT UNSCREW THE TWO
SCREWS INDICATED ON THE DRAWING. THESE FASTEN THE PRINTED
CIRCUIT BOARD TO THE LOWER HOUSING. UNSCREW THE SIX (6)
REMAINING METAL PHILLIPS HEAD SCREWS AND ONE (1) NYLON NON-
CONDUCTIVE 3/16" HEX HEAD SCREW. USE 3/16" NUT DRIVER. TURN
THE PRINTER/CHARGER OVER AND GENTLY LIFT THE TOP PANEL
OFF. COMPARE ROUTING AND CONNECTION OF FLEX CIRCUITS TO
ASSEMBLY DRAWING. INSPECT FOR TEARS AT THE PLUGS. UNPLUG
THESE TWO FLEX CIRCUITS FROM THE PCB. REMOVE THE TOP
PANEL. 8

K PRINTER AND/OR PCB REPLACEMENT.
FIGURE I - 1 UNFASTENING TOP PANEL *
*Unfasten the top panel by removing all screws as shown in the figure above,
except the two screws marked with arrows. These two screws hold the PCB to
the lower housing. Remove them if the PCB is to be removed after the top
panel is off.
NOTE:
USE 3/16" NYLON HEX HEAD SCREW IN LOCATION AS SHOWN IN ABOVE FIG-
URE. TIGHTEN UNTIL HEAD OF SCREW IS IN CONTACT WITH CASE.
9

K PRINTER AND/OR PCB
K3.REMOVE PRINTER AND PCB FROM PRINTER/CHARGER HOUSING.
TURN THE HOUSING ON END AND SUPPORT THE PCB FROM WITHIN
WHILE UNSCREWING TWO REMAINING SCREWS AND NUTS. LIFT THE
PRINTER/PCB ASSEMBLY PARTIALLY OUT OF THE CASE TO ALLOW YOU
TO DISCONNECT THE THREE POWER LEADS FROM THE EMI FILTER. BE
CAREFUL NOT TO BEND THE DIP SWITCH ASSEMBLY.
K4.REMOVE PRINTER FROM PCB.
UNPLUG CONNECTOR FROM PRINTER. PARTIALLY UNSCREW
FOUR SCREWS ONLY AS FAR AS NEEDED TO DISENGAGE THE
PRINTER. SLIDE THE PRINTER OUT FROM UNDER THE GEAR
COVER. THIS METHOD WILL KEEP THE FOUR STANDOFFS CAPTIVE
ON THE SCREW THUS ELIMINATING HAVING TO REPOSITION THEM
WHEN INSTALLING THE REPLACEMENT PRINTER. IF YOU REMOVE
THE FOUR SCREWS ENTIRELY, THE FOUR SMALL PLASTIC STAND-
OFFS WILL FALL OUT FROM UNDERNEATH THE BLACK PAPER
WELL. IF THEY DO FALL OUT, ROTATE PAPER WELL OUT OF THE
WAY AND USE SUPER GLUE TO HOLD STANDOFFS TO BOARD
WITH 1/64" DOT OF GLUE TO THE STANDOFF. ATTACH STANDOFFS
TO THE BOARD. ROTATE PAPER WELL OVER BOARD AND ALIGN
HOLES WITH STANDOFFS.
REPLACE PRINTER
K5.ATTACH REPLACEMENT PRINTER TO PAPER WELL/PCB.
SLIDE REPLACEMENT PRINTER UNDER GEAR COVER AND ALIGN
SCREW HOLES IN PRINTER WITH HOLES IN PCB/PAPER WELL.
SECURE PRINTER TO PCB/BOARD ASSEMBLY WITH FOUR
SCREWS. CONNECT CIRCUIT CONNECTOR TO PRINTER.
K6.REPLACE PRINTER/PCB INTO HOUSING.
POSITION THE PCB OVER THE HOUSING AND CONNECT THE
POWER LEADS TO THE EMI FILTER. SECURE THE PCB TO THE
CASE WITH TWO SCREWS AND NUTS AS SHOWN BY ARROWS IN
FIG. I - 1.
K7.ATTACH TOP PANEL TO CASE.
POSITION THE TOP PANEL OVER THE CASE AND CONNECT THE
KEYPAD FLEX CIRCUIT TO THE PCB. CHECK FOR TWISTS IN FLEX
CIRCUIT. CONNECT THE CONTACT HOUSING ASSEMBLY FLEX
CIRCUIT (BLACK SIDE FACING PRINTER WELL OR PIN 1 OF FLEX TO
PIN 1 ON PCB) TO THE MAIN PCB. LOWER THE TOP PANEL
SLOWLY AND MAKE SURE CONTACT HOUSING FLEX IS AROUND
STANDOFF. REFER TO FIG. I-1 AND SECURE TOP PANEL TO THE
CASE WITH SIX PHILLIPS HEAD SCREWS AND ONE 3/16" HEX HEAD
NYLON SCREW. USE 3/16" NUT DRIVER AND SLOWLY TIGHTEN
UNTIL THE HEAD OF THE SCREW CONTACTS THE CASE.
K8.INSERT PAPER AND PAPER ACCESS DOOR.
REFER TO OPERATING INSTRUCTIONS PAGES C-48 AN C-49 FOR
PAPER REPLACEMENT.
K9.TEST PRINTER CHARGER.
FOLLOW INSTRUCTIONS A SPEC “ MANUF. INSTRUCTIONS
STATION 5 TEST AND SHIP” IN SECTION 12.
10

SECTION 2
PRELIMINARY BENCH TEST FOR MICROTYMP 2 23641
• Purpose of test: Tests MicroTymp 2 for: 1 Leaks, 2 Vent rate, 3 Noise,
4 Recharge, 5 Inactive current drain, 6 Active current drain. These tests help
prevent aborted calibration cycles in Calvin, thus saving time. The technician
can resolve MT2 handle problems before starting the recal process.
• How Performed: Perform tests in series in numerical sequence.
• When Performed: Before recalibration.
• Required Equipment: Welch Allyn Calvin Recalibration system, Digital Volt Ohm
meter, Pressure Box T-5657 or equivalent pressure source (400 dPa max, with 1
dPa resolution on digital display), fully charged battery.
Test 1 Leaks
1.1 — Open MT2 and remove battery.
1.2 — Momentarily apply 7.2 VDC across valve coil to latch valve closed.
See FIG 1.2 for polarity.
1.3 — Connect Pressure Box (T-5657) pressure tube to MT2 probe tip while
valve is latched closed.
1.4 — Adjust pressure of T-5657 to 200 dPa and observe leak rate.
Must leak less than 10 dPa in 5 seconds.
1.5 — Throw Pressure/Vent switch to V (vent).
1.6 — Throw Select switch to Negative. (This will cause meter to read positive with
negative pressure.)
1.7 — Throw Pressure/Vent switch to Pressure
1.8 — Adjust pressure of T-5657 down to -400 dPa and observe leak rate.
Must leak less than 10 dPa in 5 seconds.
1
Apply 7.2 Volts D.C. momentarily to close valve.
Valve will 'latch' and hold closed position.
Figure 1.2 Closing Valve for leak check procedure.
Probe end Valve
— 7.2 v +
Empty Battery
compartment

Preliminary Bench Test for MicroTymp 2 23641 continued:
Test 2 Vent Rate
2.1 — Momentarily apply 7.2 VDC across valve coil (with reverse polarity) to open
(unlatch) valve. See FIG 2.1 for polarity. This will vent -400 dPa from step 1.8.
2.2 — Observe pressure reading on T-5657. Pressure should vent from -400 dPa
to 0 dPa in 1 second or less.
Test 3 Noise
3.1 — Put .2 cc cavity onto the probe tip.
3.2 — Take Tympanogram of cavity by depressing and releasing black test button.
3.3 — Observe for noise. Repeat 5 times.
3.4 — Observe the number of rows above baseline. None is ideal. One row is
acceptable. Two or more lines above baseline is unacceptable and constitutes
a failure.
3.5 — Repeat steps 3.2 to 3.4 with 1.0 cc, 2.0 cc and 2.4 cc cavities.
2
Apply 7.2 Volts D.C. momentarily to open valve.
Valve will 'un-latch' and hold an open position.
Figure 1.2 Opening Valve to test Vent Rate
Probe end Valve
+ 7.2 v —
Empty Battery
compartment

Preliminary Bench Test for MicroTymp 2 23641 continued:
Test 4 Recharge
4.1 — Establish and maintain 7.2 VDC to handle charge contacts. Polarity is
shown in FIG 4.1
4.2 — Snap the negative end of a fully charged battery into negative battery clips
with the battery positive end tipped up at about 45 degrees. The positive
spring must not touch the positive end of the battery. (only the negative
end of the battery makes contact with the battery compartment negative
contacts as shown in FIG 4.1 below.
4.3 — Connect Milliammeter ( - ) Negative lead to positive side of the battery as
per FIG 4.1 below.
4.4 — Connect Milliammeter (+) Positive lead to the positive spring in the battery
compartment as per FIG 4.1 below.
4.5 — Observe Ammeter reading. Current will be 60 mA +/- 5 mA.
4.6 — Remove Ammeter leads from circuit.
4.7 — Remove 7.2 volt power supply leads from handle charge contacts.
4.8 — Check resistance between the two side contacts. Value must read between 3.8
KVand 4.0 KV. If resistance is too low, check C17, C18 and C19.
Figure 4.1 Recharge Current
Probe end Valve
60 mA
– Milliamps +
battery +–+
+ 7.2 v —
applied to MT2
3

Preliminary Bench Test for MicroTymp 2 23641 continued:
Test 5 Inactive Current Drain
5.1 — Keep battery in partially installed position as in step 4.2 above.
5.2 — Connect Milliammeter ( - ) Negative lead to positive spring contact in the battery
compartment as per FIG 5.2
5.3 — Connect Milliammeter (+) Positive lead to positive side of battery . FIG 5.2
5.4 — Observe current drain. Current will be less than 1 milliamp, typically 500-600
microamps. Note: One possible cause of failure is shorted capacitor C11.
5.5 — Leave all connections as they are for the next test.
Test 6 Active Current Drain
6.1 — Depress and hold black center push button to activate MT2.
6.2 — Observe current drain while the black button is depressed. Current can rise up
to as much as 350 mA +/- 50 mA , then fall to 175 mA +/- 25 mA..
6.3 — Release black button. Current will fall to 135 mA +/- 25 mA.
6.4 — If readings are normal, calibrate with Calvin equipment.
4
Figure 5.2 Current Drain
Probe end Valve
+ Milliamps –
battery +– +
Inactive current drain 500 600 microamps
Button IN Active current drain 175 +/- 25 mA
Button OUT Active Current drain 135 +/- 25mA