Welch Allyn LS100 User manual

Exam/Procediure Light
Operation Manual
WELCH ALLYN
LS100 HALOGEN LIGHT
SERVICE MANUAL
WA
WELCH ALLYN
4341 State Street Road
P.O. Box 220
Skaneateles Falls, NY 13153-0220
Technical Service Dept:
Telephone: [phone]
Fax: [phone]
1

SERVICE MANUAL
FOR:
WELCH ALLYN
LSI00 HALOGEN LIGHT
MODELS: 44100 ... Domestic
44110...Wall/Table mount
Copyright 1994,
Welch Allyn Co.
4341 State Street Road
P.O. Box 220
Skaneateles Falls, NY 13153-0220
Originator: Richard Settembre cad file name:440082B.WP5
ECN# 5-29487 SERVICE MANUAL PN 440088 REV.B
11/94
2

TABLE OF CONTENTS
FORWARD --------------------------3
SAFE SERVICE -----------------------4
INDEX: FAILURE/CAUSE ------------------- 5 - 6
INDEX: REMOVAL/REPLACEMENT (R & R) PROCEDURES ------ 7
REMOVAL/REPLACEMENT PROCEDURES --------------8-22
APPENDIX
SERVICE PARTS LIST AND EXPLODED DIAGRAM
* * * *
AA
WIRING DIAGRAM/SCHEMATIC DIAGRAM
* * * *
BB
REPAIR VERIFICATION TEST PROCEDURES
* * * *
CC
PACKAGING FOR SHIPMENT
* * * *
DD
LIST OF SAFETY/ADVISORY/USE LABELS
* * * *
EE
TOOLS (COMMON & SPECIAL)
* * * *
FF
PRODUCT UP-DATES
* * * *
GG
PRODUCT DESCRIPTION
* * * *
HH

FORWARD
3
This SERVICE MANUAL provides technical assistance to Welch
Allyn repair technicians for diagnosing, repairing, and testing
the WELCH ALLYN LS100 HALOGEN LIGHT. The manual's main content
areas cover: troubleshooting, step by step repair, adjustment, and
re-test procedures. The repair 'TASK' procedures (R & R
Removal and Replacement) are written to provide quick and easy
reference for repair technicians of different experience levels.
Required specifications and materials are listed at each step
where applicable. When reading this manual for the first time,
have an LS100 readily available for reference and practice. Read
each complete repair step on what to do (task statement), plus how
to do it (technique statement) before starting the repair or
practice.
Training for the LS100 should consist of detailed
demonstrations of required repair tasks, practice on LSIOO'S using
repair tooling and materials. Assess skill development through
observation of trainee practice on actual equipment. Set up
sessions to allow the trainee to practice the use of the
diagnostic, repair, adjustment, and re-testing procedures found in
this manual. 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 demonstrated 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 technicians.
IMPORTANT :
Welch Allyn part numbers and 'M' (material) numbers appearing
in this manual are for the purpose of familiarizing new
technicians with Welch Allyn documentation conventions. 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.
Notices announcing these changes should be attached to PRODUCT
UPDATES APPENDIX.
HOW TO FIND CURRENT PART NUMBER INFORMATION:
REFER TO THE MOST RECENT ASSEMBLY DRAWING(S) FOR APPLICATION
INFORMATION ON PARTS, PROCESS, AND MATERIALS. FIND THE CURRENT
PART NUMBERS BY REFERRING TO THE CIRCLED NUMBERS ('BUBBLE'
NUMBERS) ON CURRENT ASSEMBLY DRAWINGS. FIND CORRESPONDING PART
NUMBER ON THE MANUFACTURING OR REPAIR BILL OF MATERIALS.

WEAR EYE PROTECTION WHEN SERVICING THIS PRODUCT ! 4
*** SAFE SERVICE ***
DISCONNECT power cord from A.C. power source before initial
disassembly of LS100 Light. OBSERVE cautions / warnings in owners
manual and printed on the product itself.
COMPLY with all safety codes and practices for this type of
product. COMPLY with all safety regulations at your work place.
PERFORM all recommended Welch Allyn service test procedures
to assure the LS100 meets all safety, performance and reliability
requirements.
EXAMINE AND REPAIR OR REPLACE as required, any and all worn
or questionable wiring, components, connections, connectors,
warning labels, insulation and other items necessary for the
continued safe operation of this product.
DO NOT TOUCH halogen lamps or nearby parts during or
immediately after operation. WAIT AT LEAST TWENTY MINUTES (20
MIN.) BEFORE TOUCHING HALOGEN LAMPS. VERY HIGH TEMPERATURES will
cause severe burns! Fractured or broken lamps may cause injury.
To prevent cuts, REMOVE such lamps by HOLDING them with a cloth or
wear work gloves. WEAR SAFETY GLASSES!
DO NOT LOOK DIRECTLY AT or TOUCH operating lamps!
*** QUALITY SERVICE ***
MODIFY your SERVICE Manual by notating changes and revisions
of part numbers and procedures. Enter this information on the
appropriate page...and include a copy of the notification in your
Appendix "Product Updates".
READ AND UNDERSTAND customer comments and complaints on
accompanying documentation (P.O. or other correspondence).
IF AN INJURY OR ILLNESS TO PATIENT OR USER, OR HAZARDOUS
MALFUNCTION HAS OCCURRED OR IS SUSPECTED, DO NOT DISASSEMBLE,
REASSEMBLE, ALTER OR REPAIR THE PRODUCT IN ANY WAY... INSTEAD, GIVE
THE UNIT AND ALL ACCOMPANYING PAPERWORK TO YOUR REPAIR SUPERVISOR.
Appropriate action per approved Welch Allyn policy will be taken.
When performing a complete inspection, LOOK for : missing
parts, product defects, damage, tampering, unsafe condition of
wiring or any component. ENTER all findings and test data along
with repair status in the appropriate file.
Most of the repairs can be performed on a foam covered work
bench. Place the LS100 in holding fixture for repairs. Take all
actions to prevent scratching the bezel.

5
INDEX: FAILURE / CAUSE
ALSO REFER TO:
ELECTRICAL SCHEMATIC, SERVICE PARTS DRAWING NOS.PN 440045 AND
440120 .
Lamp does not illuminate. no voltage at A.C. source.
CHECK measure and restore voltage.
. lamp filament burned, "OPEN"
circuit.
Visually inspect filament. REPLACE
open lamp.
. defective switch, "OPEN" circuit
CHECK voltage across switch in
closed position. If voltage is 13.5
v.a.c. to 15.0 +/- 0.3 V.A.C.,
then switch s defective. REPLACE switch.
. defective transformer, "OPEN"
primary or secondary windings or
defective or "failed OPEN" thermal
protection device in transformer
primary winding.
CHECKcontinuity/ohms of transformer
primary winding. REPLACE if 'open'.
There is NO fuse or circuit breaker
in the LS100. When the temperature
of the transformer primary winding
decreases to a pre-set value as
determined by the manufacturer, the
automatic thermal protection device
will automatically restore to a
closed or 'passing' condition.
.... "OPEN" circuit in power cord or
connecting wires and connectors.
REPLACE defective component.
Lamp is not bright .... Wrong lamp or supply voltage
.... high resistance in wiring
.... defective transformer
Lamp turns off after
short time illuminated .... transformer is operating at high
temperature thus activating
internal thermal protection device.
REPLACE transformer.
.... lamp is of too high wattage,(over
22 watts) and is overloading
transformer. INSTALL correct lamp.
loose connection in wiring or lamp
is loose in lamp socket. RESTORE
connections/REPLACE socket.
Lamp is intermittent
when LS100 is touched or
moved

INDEX: FAILURE / CAUSE CONTINUED
6
Switch produces arc or
flash when operated .... switch is defective or wiring
connections are not secure.
Fails Dielectric strength.... replace transformer/power cord
assembly
.... 1. remove the base mount plate and
inspect the ground connection
between the power cord ground pin
and the base plate. Test for
Continuity.
2 . if step 1 above shows good
connection, then the 'open circuit'
is in the power cord. Replace
entire transformer/power cord
assembly.
....replace the entire transformer/power
cord assembly.
LSI 00 WALL / TABLE MOUNT TROUBLESHOOTING
No light output .... broken lamp (broken pins, filament,
glass envelope,) REPLACE lamp.
.... defective switch (failed open),
replace switch. Note: there should
be 14.0 Vac +/-.5 Vac the
transformer output (no load). Lamp
resistance is about one ohm.
.... no transformer output (defective
transformer or transformer fuse.)
REPLACE defective component.
.... transformer output (secondary) ohms
above 1.2 ohms..defective winding.
REPLACE transformer.
.... transformer input (primary) ohms
above 25 ohms (75 ohms for export
models), defective (open) primary
or thermal fuse. REPLACE
transformer.
.... cable broken. INSPECT , REPLACE
transformer.
no load output of transformer is
than 14.0 volts. Defective
transformer. REPLACE transformer.
Fails ground continuity
testing
Fails leakage current
testing
Transformer is hot
less

INDEX: REMOVAL AND REPLACEMENT (R & R) PROCEDURES 7
CAUTION : DISCONNECT LS100 FROM A.C. POWER SOURCE
BEFORE SERVICING TO
AVOID ELECTRICAL SHOCK HAZARD
Component: Page:
A Halogen Lamp
B Power Switch
C Transformer/Power Cord Assembly-
D Bezel
E Reflector
F Light Cap
G Hinge 'Stand-off'
H Lamp Socket
I Light Housing
J Flexible 'Gooseneck' Assembly
K Pole
L Wall and table mount LS100
M Gooseneck for model Wall/Table -
N Table bracket assembly
8
9
10-11
11-13
13-14
14
15
15
16
17- 1 8
18- 1 9
20
21
22
ECN# 5-29487 SERVICE MANUAL PN 440088 REV.B 11/94

CAUTION: DISCONNECT LS100 FROM POWER SOURCE BEFORE SERVICING 8
A HALOGEN LAMP (R & R) PN06300
A 1. OPEN LIGHT CAP PN44024
PRESS TWO TABS OR DETENTS ON OPPOSITE SIDES OF LIGHT
CAP WHILE AT THE SAME TIME LIFTING LIGHT CAP. PULL OPEN
TO EXPOSE LAMP AND LAMP SOCKET.
A 2. REMOVE HALOGEN LAMP PN06300
CAUTION: EXERCISE CAUTION SINCE LAMP QUARTZ ENVELOPE MAY BE:
FRACTURED, CRACKED, OR HOT. USE A CLOTH TO HOLD THE
OLD LAMP WHEN PULLING OLD LAMP OUT OF SOCKET. DO NOT
TWIST LAMP...THIS WILL BREAK THE PINS FROM THE LAMP.
SUPPORT LIGHT CAP WITH ONE HAND AND GENTLY PULL OLD
LAMP STRAIGHT OUT WITH THE OTHER HAND. REMOVE BROKEN
LAMP PARTS OR PINS FROM SOCKET WITH A LONG NOSE PLIERS.
A 3. REPLACE LAMP WITH NEW HALOGEN LAMP PN06300
DO NOT TOUCH NEW LAMP WITH YOUR FINGERS. FINGER GREASE
OR OTHER CONTAMINANTS WILL DARKEN ON THE QUARTZ
ENVELOPE AND CAUSE DISCOLORATION AND PREMATURE FAILURE
OF THE REPLACEMENT LAMP. CLEAN LAMP BEFORE PLACING IN
SOCKET. USE A TISSUE OR OTHER CLEAN CLOTH TO HOLD THE
LAMP WITH WHILE INSERTING IT INTO THE SOCKET. SUPPORT
LIGHT CAP WITH YOUR OPPOSITE HAND WHILE INSERTING LAMP
STRAIGHT INTO LAMP SOCKET. VERIFY PROPER ALIGNMENT AND
A SECURE CONNECTION BETWEEN LAMP AND LAMP SOCKET.
A 4. RESTORE LIGHT CAP TO ORIGINAL CLOSED POSITION
CLOSE THE LIGHT CAP AND VERIFY THAT BOTH TABS HAVE
FULLY ENGAGED TO SECURE THE LIGHT CAP IN CLOSED
POSITION. TEST BY TRYING TO OPEN LIGHT CAP WITHOUT
DEPRESSING TABS. LIGHT CAP SHOULD NOT OPEN.
A 5. VERIFY REPAIR
CONNECT LSI0 0 TO POWER SOURCE AND TURN LIGHT ON. ALLOW
NEW LAMP TO OPERATE AT LEAST FIVE MINUTES TO 'BURN IN'.
TECHNICIAN
NOTES :

CAUTION: DISCONNECT LS100 FROM POWER SOURCE BEFORE SERVICING 9
B POWER SWITCH (R & R) PN440029
B 1. REMOVE SWITCH PN44029
APPLY A SMALL PIECE OF MASKING TAPE AT ONE END OF THE
SWITCH TO PROTECT THE LIGHT HOUSING TOP FROM MARKING BY
TOOLS DURING SWITCH REMOVAL. PULL SWITCH OUT OF THE
LIGHT HOUSING PN440023-2 BY PRYING UPWARDS AT THE END
OF THE SWITCH WITH A THIN EDGE SUCH AS A PUTTY KNIFE.
B 2. DISCONNECT WIRES FROM SWITCH
UNPLUG BOTH WIRES FROM THE BOTTOM OF THE SWITCH.
B 3. INSTALL NEW SWITCH
ATTACH WIRES AND PRESS SWITCH INTO LIGHT HOUSING,
MAKING SURE THAT THE "0" LABEL ON THE TOP OF THE SWITCH
IS TOWARDS THE GOOSENECK. SINCE THESE WIRES CARRY 12
VOLTS A.C., THE WIRES MAY BE ATTACHED TO THE SWITCH IN
EITHER POSITION. REFER TO WIRING DIAGRAM IN APPENDIX
BB.
B 4. VERIFY REPAIR
CONNECT LS100 TO POWER SOURCE AND OPERATE THE LAMP A
NUMBER OF TIMES TO DETERMINE THAT THE SWITCH IS
OPERATING PROPERLY.
CAUTION: DISCONNECT LS100 FROM POWER SOURCE BEFORE SERVICING
C TRANSFORMER/POWER CORD ASSEMBLY (R & R) PN-*
* part number for country of use, see parts list in catalog.
C 1. REMOVE BASE MOUNT PLATE PN440035-501
UNPLUG THE A.C. POWER CORD AND PLACE THE LSI0 0 IN A
HORIZONTAL POSITION. UN-SCREW FIVE (5) FASTENERS (1/4-
20) PN10 6140-1 STARTING WITH THE CENTER FASTENER. IT IS
SECURED WITH LOCKTITE 262-31 (RED PN M30328), AND WILL
REQUIRE MORE TORQUE (OR HEAT FROM SOLDERING IRON
APPLIED TO SCREW HEAD) TO UNFASTEN. THE CENTER SCREW
IS THREADED INTO AN ALUMINUM INSERT IN THE BASE OF THE
POLE. (NOT A SEPARATE PART NUMBER). HOLD THE POLE
FIRMLY WITH ONE HAND WHILE LOOSENING THE CENTER SCREW
WITH A VISE-GRIP LOCKING PLIERS (FOR PHILLIPS SCREWS
USE A VISE GRIP..FOR MODELS THAT HAVE OTHER TYPES OF
FASTENERS, USE APPROPRIATE TOOL). SUPPORT THE BASE
PLATE WHEN IT SEPARATES FROM THE PLASTIC BASE. THIS
WILL PROTECT THE WIRES AND CONNECTIONS FROM BEING
PULLED BY THE WEIGHT OF THE TRANSFORMER AND METAL BASE
PLATE. IF REPLACING BASE PLATE, TRANSFER MANUFACTURE
DATE AND LABEL TO NEW BASE.