Section 17
This manual is now part of the Traditional Instruments Service Manual
Binocular Indirect Ophthalmoscope
B. I. O. Model 12000
Model# Model Name Section Page
12000 B.I.O. 1 3 -7
74101 Battery Pack 2 8
74141 B.I.O. Wall Bracket 3 9-10
All Required T ools 4 1 1
All Figures 1.7, 1.10 A&B 5 12-13
1
Special Instructions for B.I.O. Service
Clean all returned items by wiping with a solution of 10% Clorox/90% water. Do not use alcohol
or other chemicals to clean to B.I.O. Inspect the unit, especially alignment prior to disassembly .
Duplicate (if possible) customer problem.
Important: Check alignment before and after service.
1. Put B.I.O. on head.
2. Look at object held in hand, arms length. If the image appears as a double image, then
the unit is misaligned. The B.I.O. unit must be evaluated on laser alignment equipment at
Welch Allyn. Return to Technical Service Dept. for evaluation and or repair . Therefore,
proceed with repairs only on units with good alignment.
2
Disassembly of Model 12000 B.I.O.
Refer to Figure 120103 in Repair Parts Catalog
Abbreviations used in text and parts list:
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1.1 Lamp Remove lamp cover .
CM
EM
CMH
IM
VS
IS
BIS
Central Mirror
Eye Mirror
Central Mirror Holder
Illumination Mirror
Viewing System
Illumination System
B.I.O. Sub-Assembly without headband
Caution!!! Lamp area will be hot after use.
Loosen the adjustment knob and slide the BIO all the way
up.
Remove the lamp from its well.
Replace with new Welch Allyn lamp.
Clean new lamp with alcohol.
Insert lamp pin with slot (pin down).
Slide lamp cover over lamp.
Verify operation of the new lamp.
1.2
VS
Housing Assembly
Unscrew and remove bracket knob.
Support the
with washer.
Remove
Remove lamp as per Step 1.1 above.
Rremove left and right outer insulators and left/right inner
ear insulators respectively .
Remove top two screws.
Pull back cover off.
Remove cable connector assembly .
Loosen bottom two screws.
Pry off and discard -+- button.
Remove two outer bottom screws.
Loosen two central screws 3 turns.
Do not remove them. This helps VS housing removal.
Remove the VS housing form the
BIS
and remove bracket screw, bracket spacer
BIS
from headband.
3
VS/IS
assemblies.
1.3 Illumination System Place BIO in fixture T-12198 to ease further
(IS)
Sub-Assembly disassembly .
Remove the two central screws that were loosened
in the previous step.
Seperate the illumination system sub-assembly from
the visual assembly .
1.4
1.5 Illumination Lenses When the two hex cap screws are removed from the
IM
Y oke Remove hair spring with tweezers.
IM
Mirror Remove IM yoke and IM mirror/mirror holder sub-
assembly for illumination system bracket.
illumination sub-assembly , it will come apart.
Hold the illumination sub-assembly on a foam mat in
a horizontal position for complete disassembly .
Remove two hex cap screws from heat sink lamp
holder. Use 3/32 hex key .
Pull Illumination system bracket away from optics
carrier.
Remove compression spring and mirror tilt control.
Remove aperture spacer assembly which contains
aperture and filter holders.
Remove heat sink lamp holder from contact holder.
Remove spring washer, wide band hot mirror disc
lens, lens spacer and lens.
1.6 VS Assembly Remove and discard rubber eye cups.
Remove and clean both eyepiece lenses.
.
End of Disassembly
4
Reassembly of Model 12000
Refer to Figure 120103 in Repair Parts Catalog
Important: Check alignment prior to reassembly of whole unit.
1.7 Aperture Filter Assy’s Clean the aperture and filter assemblies before installing in
aperture spacers.
Place the aperture spacers side by side as in Figure 1.7.
T op spacer is put on left. Bottom spacer is put on right.
Place a spring waher in the right circle recess of each
aperture spacer as shown in Figure 1.7.
Place aperture assembly, with the black aperture mask
facing up, into the left (top) aperture spacer, on top of the
washer .
Engage the detent with the aperture assembly .
Carefully pick up left (top) aperture spacer and turn it over.
Lay it on top of the other aperture spacer.
Hold the aperture spacers together with one hand and
operate the levers of the aperture and filter assemblies.
Keep this orientation. After assembly , the filter lever must
be on the right side.
1.8 Illumination System Clean the objective lens and all parts of illumination
Bracket IS lenses system.
Place the objective lens (convex down) into the
Place a lower aperture over the objective lens.
Press objective lens retainer into the IS bracket (over the
lower aperture). Use tool T-12169.
Place IM yoke and mirror assembly together . Use new
hair spring.
Place yoke and mirror assembly onto the
Place the VS subassembly into assembly nest T-12198.
Attach the IS bracket assembly to the
with two chassis screws.
Place mirror tilt control in hole in
Insert compression spring into hole in mirror tilt control.
Place the aperture assembly built in Step 1.7 into assembly
nest T-12196 (aperture side up)
n Note: If assembled correctly , the filter lever will be on the right side of the aperture
assembly .
Place a clean lens on top of aperture spacer (round side
up).
IS
bracket.
VS
IS
bracket.
IS
bracket.
subassembly
5
Reassembly of Model 12000 cont’d
1.9 Optics Carrier Place optics carrier (ears up), over lens of aperture spacer
IS
lenses and assembly (lower lens.)
components Place lens spacer into optics carrier, over lower lens.
Place upper lens (round side down) on top of lens spacer.
Place hot mirror disc on top of lens.
Place wide band hot mirror (coated side up), over hot
mirror disc. See
coated side of hot mirror.
Place spring washer over wide band hot mirror.
1.10 Heat Sink Lamp Place contact holder onto lamp socket of heat sink lamp
holder holder.
Lower this assembly onto the optics carrier . All layers of
this assembly must be held securely together.
Pick up this assembly and place it onto the IS bracket.
Insert two long hex head cap screws into heat sink lamp
holder.
Tighten cap screws. Use 3/32” hex key .
Check illumination system for dirt.
Figure 1.10
for correct orientation of
1.1 1 Power Cord Place the contact/cord assembly through left slot of
textured side of back cover .
Place the optics assembly into nest T-12100.
Insert the contacts into the slots of the lamp carrier
assembly (white wire on left, black wire on right).
Press the wire into wire groove.
Place the back cover on to the optics assembly.
Attach the back cover to the optics assembly with screw
between ear insulators.
Tighten screw.
Place lamp into lamp holder .
1.12
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n Note: Lower two screw heads must not interfer with slider motion.
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VS
Housing Place the CM slider onto the bottom of VS chassis
assembly .
Loosen the two center chassis screws holding IS to the VS.
Place the optics section into housing.
Retighten these two chassis screws.
Install one short and two long screws into assembly .
6
1.12
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n Note: Lower two screw heads must not interfer with slider motion.
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1.13 Lamp Cover Inspect that lamp is all the way into heat sink lamp housing.
1.14 Head band bracket Attach BIO to the headband browband.
VS
Housing cont’d
Insert the tabs of new CMH button in CM slider at the
bottom of thehousing.
Attach inner and outer left insulator ears.
Clean both eyepiece lenses.
Insert eyepiece lenses.
n Plano lenses: insert either way
n +2 Diopter lenses: insert concave side out
Install new rubber eye cups.
Slide the lamp cover down into the assembly .
Insert bracket screw through slotted holes so that it
passes through spacer and washer . Washer will be on
knob side of the bracket.
Attach knob and tighten finger tight.
1.15 Test BIO Put BIO on head.
Look at object held in hand, arms length. If the image
appears as a double image, then the unit is misaligned.
Some part of the visual system has become damaged and
misaligned. The unit must be evaluated on laser alignment
equipment at Welch Allyn. Return unit to Welch Allyn
T echnical Service Dept. for evaluation and or repair .
End Reassembly
7
Model 74201 Battery Pack
2.1 Back Case Unscrew and remove two screws from back of battery
pack.
Carefully separate back of case from front case.
2.2 Battery Unplug battery from circuit board.
2.3 Circuit Board Pull knob off.
Unscrew potentiometer nut.
Gently pull board straight out of front case.
End Disassembly of 74201 Battery Pack
Reassembly
2.4 Circuit Board Insert replacement circuit board into front case.
Place hex nut on potentiometer and tighten.
Position knob on end of shaft with flat of shaft aligned with
spring clip of knob.
2.5 Battery Plug a fully charged battery into circuit board connector .
Place battery into case with wire exiting battery on
lower left side.
Place connector in space on knob side of case.
2.6 Back Case Engage back case to front case at bottom.
Gently push on circuit board at side opposite knob so that
cases will come together.
Gently press cases together at top.
Secure with two phillips head screws.
End of Reassembly of 74201 Battery Pack
8
Model 74241 Wall Bracket Disassembly
3.1 Back Cover Remove two screws at back of wall bracket.
Pull back cover off at the screw end. It will hinge at the
tabs on opposite end.
3.2 Wiring Harness Remove knob by pulling straight off.
Unscrew hex nut from potentiometer.
Reach inside and pull indicator lamp from hole in case.
Pull spade connectors from micro-switch.
3.3 Microswitch Actuator Unscrew two nuts from studs.
Remove star washers.
Pull micro-switch from two studs.
Pull actuator from case.
End Disassembly 74241 Wall Bracket
Model 74241 Wall Bracket Reassembly
3.4 Microswitch Actuator Position micro switch with actuator towards screw
holes in back cover .
Secure with two star washers and nuts.
Position actuator into slot in case.
Press it up and down to assure it operated freely .
3.5 Wiring Harness Insert shaft of potentiometer through hole in heat sink plate.
Position potentiometer shaft through hole in the case.
Make sure that the alignment tab of the potentiometer is
inserted into the hole next to potentiometer shaft hole.
Tighten potentiometer shaft nut.
Insert pilot light hole in case over split tang molded onto
case.
Put “power in” jack in other slot closest to rear of case.
(Two wires go to this jack).
Put “power out” jack in other slot closest to front of case. (3
wires go to this jack).
Attach spade connectors from harness to micro switch.
9
Model 74241 Wall Bracket Reassembly cont’d
3.6 Back Cover Engage tabs and back cover into slots of case.
Close back cover onto case.
Operate black actuator to assure that it is operating micro
switch.
Insert and tighten two screws.
End Reassembly of 74241 Wall Bracket
10
Required T ools for BIO
General purpose tools:
3/32” hex key
Peer #7 tweezers
#2 phillips screwdriver (Cresent #2501)
Long nose pliers (Xcelite 91 cg)
Welch Allyn T ools and Fixtures:
T-12169 Lens retainer push tool
T-12196 Optics system assembly nest
T-12291 Electrical contact assembly nest
T-12198 Final Illumination assembly
11
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