Welch Allyn 49540 User manual

Welch Allyn Multi Fiber
Illumination Headlight
System
Service Manual
Models: 49540,49520,49522,49524, 49526
Copyright 1997
Welch Allyn Inc.
4341 State Street Road
Skaneateles Falls, NY 13153-0220
Part Number 495623 Rev A.

Service Manual Welch Allyn Fiber Optic Headlight System
Introduction Page 2
Revision (History) Page
Rev. Description of Change ECN # Date Initial
A New Release 5-34457 1/14/97 JSJ/MD

Service Manual Welch Allyn Fiber Optic Headlight System
Introduction Page 3
To Service Personnel:
The information in this manual is 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 the Welch Allyn Product Service Department
at 4341 State Street Road, Skaneateles Falls, New York 13153-0220, 1 800 669-
9771, [phone]
This product has been designed to provide a high degree of safety and
reliability. However, 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 Welch Allyn replacement parts. Failure to do so will invalidate
the product warranty.
Authorized service centers should refer to repair specification for proper test
and device history record requirements.
Please refer to the product warranty for specific coverage.
Welch Allyn, Inc.
Medical Products
4341 State Street Road
Skaneateles Falls, New York 13153-0220
USA
1 800 669-9771
[phone]

Service Manual Welch Allyn Fiber Optic Headlight System
Introduction Page 4
Service Manual
Welch Allyn Fiber Optic Headlight System
Table of Contents
Part Number Model name Section Page
49540 Luminaire
Disassembly / Repair 1 6-11
49540 Suspension Repair/Adjustment 1 11
495591-502 Headband Assembly 2 12
49543 Fiber optic cable 2 12
all Required tools 3 13
all Problem Solving 4 14
all Recommended spare parts Appendix A 15-16
all Drawings and Figures Appendix A
If you have technical questions, or need other assistance, call Welch Allyn
customer service personnel at 1-800-669-9771.
Cleaning Warnings:
DO NOT IMMERSE the Luminaire in any type of liquid. Do
not spray it heavily with any type of liquid. The liquid might enter the Luminaire
and create a service problem. DO NOT AUTOCLAVE the whole Luminaire. Only
the Joystick is autoclavable separately.
Follow Cleaning and Maintenance instructions in Owner's Manual PN495608.
Caution: Turn off light source before disconnecting fiber optic bundle from headlight or
light source. Clean exterior surfaces of Luminaire, headband, and fiber optic bundle by
wiping clean with any of these solutions: Banicide, Cidex, Cidex Plus, Cidex 7,
Metracide, 10% Wescodyne, 10% chlorine bleach, 70% Isopropyl alcohol, Wavecide-
01, mild soap and water solution.

Service Manual Welch Allyn Fiber Optic Headlight System
Introduction Page 5
Table of Reference Drawings (Appendix A)
Drawing # Description
495540 Welch Allyn Headlight Main Assembly . . .
495570
495550
Suspension / Luminaire Assembly ......
LuminaireAssembly .................
Note that drawings within this manual are for reference only. Consult factory for
current revisions.

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 6
Abstract of disassembly and reassembly of 49540 Luminaire:
The whole luminaire can be disassembled with the exception of the Mirror and
back plate which are pinned and glued to the bottom housing. If moisture is
present in the luminaire, replace the iris assembly and clean the lenses by
following instructions in this manual. With the exception of the mirror, all
components can be replaced as necessary.
The following is the process for completely disassembling and reassembling the
luminaire for 'O' ring replacement. "O" rings are used not to seal out moisture
but to provide a smooth moveable connection between parts. Only replace 'O'
rings if they are worn, cracked, stretched out or missing. If the iris control sleeve
is too loose, then the O rings have failed.
1.1 Removing O rings:
__Unscrew joystick from the lower housing.
__Unscrew the bezel from the luminaire. Use the appropriate collet
or equivalent. The bezel is glued on.
__Unscrew the top nut. Use collet or equivalent.
__Pull the top cap off of lens housing.
__Remove O rings.
1.2 Remove Bottom Housing:
__Unscrew bottom housing from lens housing. These parts are
held together using a thread locking adhesive. Use of a collet
will be needed to break the bind of the thread locker.
Note: the back plate and the mirror can not be replaced as they are pinned and
glued into the bottom housing. If the mirror is broken or loose, replace the
complete bottom housing assembly.
1.3 Remove Iris Assembly:
__Unscrew the small pin in the side of the control sleeve.
Use 1/16" flat blade screwdriver.
Note: If the iris pin is sheared, it might be removed by grabbing it
with a small diagonal cutters and unscrewing it. If not, replace lens
housing Asy.
__Pull control sleeve from the lens housing.
__Remove 'O' rings.
__Unscrew the iris retaining nut using the Welch Allyn tool
T-14452 or equivalent.

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 7
__Heat the 2-56 setscrew holding the iris in place before
attempting to loosen it. The setscrew can be heated by
inserting the hex key into the setscrew and applying heat from a
soldering iron to the hex key wrench.
__Unscrew the 2-56 setscrew holding the iris in place. Use a
.035" hex key.
__Remove the iris.
1.4 Remove Condensing
Lenses and spacers
__Heat the three 2-56 setscrews before loosening due to the
threadlocker that is used. The setscrew can be heated by
inserting the hex key into the setscrew and applying heat from a
soldering iron to the hex key wrench. If the set screws become
stripped, then the entire lens and iris assembly will need to be
replaced.
__Unscrew the three 2-56 setscrews from the lens housing. Use a
.035" hex key.
__Remove: the spacer, condensing lens, spacer, and small
condensing lens.

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 8
Re-assembly of model 49540 Luminaire
Special notes for reassembly of Luminaire:
Refer to assembly drawing 495550 in this manual.
Use new set screws and 'O' rings when reassembling luminaire.
Remove any threadlocking adhesive from parts by chasing threads with taps or
dies.
Do not touch lenses or mirror with fingers. Clean them with cotton swabs and
lens cleaner.
1.5 Install Condensing
Lenses and spacers
__Insert clean condensing lens into the lens housing so that the
convex portion is up.
__Insert a condensing lens spacer into the Lens housing so the
large diameter is facing up. Push it down onto the condensing
lens.
__Insert the next lens (This lens is the same on both sides) into
the lens housing on top of the condensing lens spacer.
1.6 Install Iris assembly
__Insert the Iris Spacer into the Lens housing chamfered end first.
Push it down so it seats on the lens fully.
__Compress the spacers and lenses together using T14601 or
equivalent. At the same time, dip a set screw into the Loctite 425
threadlocker and Install it into one of the three holes in the Lens
housing using a .035" Hex wrench.
__Install the Iris into the lens housing, with the retaining clip of the
Iris assembly facing upwards. There is a slot in the side of the Iris
which has a tapped hole located in it. Align this tapped hole with
the slot in the Lens housing.
__Screw T14600 through the slot in the lens housing and into the
Iris; finger tighten. Note: This is temporary and will be removed
after the Iris is locked into place with the Iris retainer.
__Insert T14448 into the Lens housing so that the pin in the center
of the tool is in the Iris opening and the rubber part of the tool rests
on the Iris. Apply light downward pressure to T14448 and at the
same time, rotate the tool clockwise. Rotating the tool will cause
the Iris pin tool 14600 to rotate until it contacts the end of the slot in
the lens housing. Continue rotating the tool until the Iris opening
closes down onto the pin of T14448.
__Rotate the Iris counter clockwise using T14600 until the tool
contacts the opposite side of the slot. Hold 14448 steady while
performing this operation.

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 9
__Install a set screw with threadlocker Loctite 425 into the top
threaded hole on the Lens housing using a .035" hex wrench; while
at the same time, apply firm pressure downward with T14448.
Note: Over tightening of this set screw will cause the Iris to bind.
__Remove tool T14448.Apply 2 to 3 drops of Loctite 425
threadlocker to the Iris retainer threads, then Install the Iris retainer
using T14452.
Note: When the Iris is at full closed position, a .090" diameter pin should not go through
the hole in the center of the Iris. Open and close the Iris; the operation should be
smooth.
1.7 Assemble Bottom Housing to Lens Housing
__Open the Iris to full open position and blow out any dust in the
lens housing assembly using an Aero duster or equivalent.
__Close Iris.
__Blow any dust out of the bottom housing assembly with an aero
duster.
__Apply 3 to 4 drops of Loctite 425 threadlocker to the large
external threads of the lens housing, and screw it into the bottom
housing. Tighten the assemblies together with the appropriate
collet.
__Place the fiber optic cable leading from the Solarc Light Source
into the top of the luminaire assembly.
__Inspect the spot for any dirt or dark spots by shinning onto a
white piece of paper. Also Rotate the Iris and check for proper
operation. Any small dust spots not noticed within 2 seconds are
generally acceptable. Large, dark or hair-like spots are not
acceptable.
1.8 Control Sleeve and Top Cap
__Install (2) large O-rings into the lower grooves on the Lens
Housing.
__Install (1) large O-ring onto the top of the first shoulder of the
Lens Housing.
__Apply a light coat of Grease to all (3) O-rings.
__Assemble the Control Sleeve over the Lens Housing and down
to the O-rings. Rotate the Control Sleeve so that the hole in the
side of it is positioned above the threaded hole in the Iris; seen
through the slot in the Lens Housing.
__Push Control Sleeve down over the O-rings until seated; being

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 10
careful not to rotate the parts.
__Apply (1) drop of Loctite Adhesive to the threads of an Iris Pin
and install through the hole in the Control Sleeve and into the Iris.
Tighten w/ a screw driver until flush or just below.
__Rotate Control Sleeve back and forth to spread grease and
check for freedom of movement.
__Install (1) large O-ring onto the Lens housing and push down until
seated on top of the Control Sleeve.
__Install (2) large O-rings into the lower exposed grooves on the Lens
Housing.
__Install (1) small O-ring onto the Lens Housing so that it sit on the
shoulder just above the last Large O-ring.
__Apply a generous coat of Grease to the 2 lower O-rings.
__Apply a coat of Grease to the inside of the Top Cap.
__Install a Top Cap onto the Lens Housing so it rests on the O-rings.
Rotate the Top Cap while pushing it down over the O-rings. Continue
until seated.
__Install (1) Small O-ring down on top of the Top Cap.
__Apply 2-3 drops of Loctite 425 Threadlocker to the Lens Housing
threads.
__Install the Top Cap Nut onto the Lens Housing and tighten with the
appropriate collet or equivalent.
__Rotate the Top Cap a few turns to make sure it rotates smoothly.

Section 1 Disassembly & Reassembly
Service Manual Welch Allyn Fiber Optic Headlight System Page 11
Abstract of disassembly and reassembly of 49540 Luminaire Suspension:
The following is the process for adjusting or repairing the luminaire suspension.
In most cases the end user will probably indicate that the luminaire no longer
stays where it is put. This condition is caused by wear to the friction washers in
the suspension mechanism or loosening of the assembly screws. The assembly
screw(s) can be tightened to compensate for the wear of the washers or in
severe cases, the washers will need to be replaced.
Special notes for repairing the Luminaire Suspension:
Refer to assembly drawing 495570 in this manual for proper reassembly and
torque specifications.
Reapply threadlocking adhesive (Loctite 425) to any screws that are tightened or
loosened. __Remove the setscrews located inside the three pivot nuts, using
a 1/16" hex key.
__Loosen the three Pivot nuts to break any of the threadlocker
free so that the nut turns freely, and blow out any loose debris left
from the old threadlocker.
__Tighten the three Pivot nuts to the specified torque as
described on drawing 495570.
__Apply a drop of Loctite 425 threadlocker onto the threads of a
setscrew and install it into one of the pivot nuts. Tighten with a
1/16" hex wrench. Repeat for the remaining two screws.

Section 2 Headband Adjustments & Repair
Service Manual Welch Allyn Fiber Optic Headlight System Page 12
Abstract of adjustment / repair of the Headband:
The following is the process for adjusting or repairing the headband. There are
only two replaceable components of the headband assembly, the three vinyl
pads (1set) and the fiber-optic clips. The fit adjustment controls can be adjusted
if the knobs are too hard to turn or if the headband will not maintain it's fit
(Loosens).
Special notes for repairing the Headband:
Refer to assembly drawing 495540 in this manual for further details.
If the vinyl pads need to be removed and reused, be sure to release snaps by
pushing a fingernail or equivalent between the two halves of the snap. The vinyl
is extremely thin and will tear if pulled on directly.
2.1 Comfort/Fit Adjustment Knob:
__Tighten the screw in the center of the adjustment knob if the
headband continues to loosen.
__Loosen the screw in the center of the adjustment knob if the
knob is too hard to turn.
2.2 Fiber Optic Clips:
__Remove the vinyl pad on the top support of the headband
assembly. See note above.
__Unscrew the two screws that hold the respective clip in place
and Remove the clip.
__Reassemble in reverse order.
Special Notes for the Fiber Optic Bundle:
The Fiber optic bundle (49543) is a multi-fiber cable which transmits the light generated at the light
source into the Luminaire Assembly. There is no repair for this item. It must be replaced if the fibers
become damaged.
Note: Refer to owner's manual (495608) for cleaning and disinfection.
Broken Fibers?:
__Hold one end of the fiber bundle up to a light and look at the other end. Dark
areas are broken fibers. The fiber optic cable will need to be replaced if the dark
area covers 20% or more of the entire bundle surface.

Section 3 Tools & Equipment
Service Manual Welch Allyn Fiber Optic Headlight System Page 13
Tools and Equipment List:
General purpose tools / supplies:
1/16" hex key
.035" hex key
Peer #7 tweezers
# 4 Flat Blade screwdriver
#2 Phillips screwdriver
#1 Phillips screwdriver
Collet Block
5C Collet for Top Nut Cap (.382")
5C Collet for Lens Housing (.438'')
5C Collet for Bezel (1.06")
Jeweler's's flat-blade screwdriver (1.5mm x 40mm) for Iris Pin.
Aero Duster ("canned air") or equivalent. Compressed air is not recommended due to oils and
moisture that are often found in compressed air.
Welch Allyn tools and fixtures:
T14600: Extended iris pin.
T14448: Iris aperture adjustment tool.
T14452: Spanner wrench for iris retainer nut.
49501 Solarc Light Source
49543 MFI Fiber Optic Cable

Section 4 Problem Solving
Service Manual Welch Allyn Fiber Optic Headlight System Page 14
Troubleshooting
Symptom Possible Cause Procedure
Low Light Output
Light Spot not defined.
Spot size control is hard to
turn.
Luminaire droops.
Headband won't keep
desired fit.
Damage has occurred to
the fiber optic cable.
The attenuator on the light
source is turned counter
clockwise.
The light source is
defective.
The Luminaire may be
flooded.
The o-rings are binding.
Friction washers in
suspension are worn out.
The fit adjustment is
slipping.
Replace the fiber optic
cable.
Adjust the attenuator to
full bright position.
Repair the light source per
service manual 495621.
Disassemble the
Luminaire and repair as
necessary.
Replace and lubricate all
o-rings.
Readjust suspension or
replace washers if
necessary.
Tighten the adjustment
screw on the appropriate
adjustment knob.

Appendix A Spare Parts List
Service Manual Welch Allyn Fiber Optic Headlight System Page 15
Part Number Description Bubble # Quantity
Luminaire Drawing Number
495562 BUNDLE CLIPS 4
495594 WASHER, COUNTERSUNK 2
495608 MANUAL 1
49571 JOYSTICK ASSY 1
495591-502 HEADBAND ASSY TAMPO 0002 1 495540
106102-25 FHPS 6-32 X.312 0004 2 495540
495565-1 LABEL 0006 1 495540
495596-502 PAD SET 0007 1 495540
495573-4 MOUNT,HEADBAND-ANODIZED 0001 1 495570
495572-3 LINKAGE, LONG-ANODIZED 0002 2 495570
106142-8 WASHER, BELVILLE (.375 OD) 0003 6 495570
106103-32 WASHER, FLAT FRICTION 0004 6 495570
495571-3 LINKAGE, SHORT-ANODIZED 0005 2 495570
495577 SPACER, HEADBAND MOUNT 0006 1 495570
495575 NUT, PIVOT 0007 3 495570
495574 SCREW, PIVOT 0008 3 495570
106113-17 SET SCREW (#6-32 X .125) 0009 3 495570
495507-3 TOP CAP NUT ANODIZED 0001 1 495550
495506-2 TOP CAP ANODIZED 0002 1 495550
495505-3 CONTROL SLEEVE ANODIZED 0003 1 495550
106104-33 O-RING 0004 2 495550
106104-32 O-RING 0005 6 495550
495513 SPRING CLIP, FERRULE 0006 1 495550
495504-1 LENS HOUSING 0007 1 495550
495901 CONDENSER LENS #1 0008 1 495550
495509 SPACER-CONDENSER LENS 0009 1 495550
495902 CONDENSER LENS #2 0010 1 495550
495510 SPACER-IRIS 0011 1 495550
710114 2-56 X 1/16 LG SET SCREW 0012 4 495550
495515 IRIS DIAPHRAGM 0013 1 495550
495517-1 PIN,IRIS 0014 1 495550

Appendix A Spare Parts List
Service Manual Welch Allyn Fiber Optic Headlight System Page 16
Part Number Description Bubble # Quantity
Luminaire Drawing Number
495516-1 RETAINER, IRIS 0015 1 495550
495501-9 BOTTOM HSG-ANODIZED 0016 1 495550
495512 JOYSTICK INSERT 0017 1 495550
495903 OBJECTIVE LENS #3 0018 1 495550
495502-3 BEZEL-OBJ LENS ANODIZED 0019 1 495550
495904-1 MIRROR 0020 1 495550
495503-6 MIRROR PLATE ANODIZED 0021 1 495550
106126-22 SPIRAL PIN, (.033 DIA X .125) 0022 2 495550
M30397 LOCTITE 330 0023 0 495550
M30398 LOCTITE 738 ACTIVATOR 0024 0 495550
M30328 LOCTITE 262-31 0026 0 495550
M30373 LOCTITE 425 ASSURE THDLOCKER 0027 0 495550
M40156 DOW CORNING 3452 LUBE 0028 0 495550