BENDIX IN-20258 User manual

ÂILLIED Bendix
~ Aerospace
1. General
Bendix General Aviation
Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
SECTION V MAINTENANCE PRACTICES
This section contains inspection procedures, cleaning information, repair
information, and semiconductor and integrated circuit service information
for the
IN-20258 Multifunction Color Indicator.
2. Inspection
Perform a routine visual inspection any time the radar indicator is removed
from the aircraft. Pay special attention to the following areas.
A. Oust Caver
Inspect the dust caver for dents, deformation or damage to the finish
that should be repaired.
B. Chassis
Inspect chassis for loose or missing hardware, deformation,
damaged
fasteners, or damaged connectors. Also check for corrosion or damage
to the finish that should be repaired.
C. Connectors
Inspect connecter
body for broken parts; check insulation for cracks.
Check pins for damage, corrosion, misalignment, or bad plating. Check
for broken, loose, or poorly soldered connections to terminals of
connectors. Inspect cable
clamps for pinched wires.
o. Terminal Connections
Inspect for corrosion
and loose connections.
E. Wi ring
Inspect chassis wiring
and subassemblies for any physical damage or
charring.
F. Capacitors
Inspect for case or
body damage and for loose, broken, or corroded
terminal connections.
G. Resistors and Diodes
Inspect for blistered, charred, or cracked bodies. Check for loose,
broken, or corroded terminal connections.
I.B.
21400C
PART 4 5-1
Mar/86
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2.
H.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Filters and Inductors
Inspect for
damage to body or casing and for loose, broken, or corroded
terminal connections.
Check for secure mounting to chassis.
1. Transformers
Inspect case for
damage and for signs of excessive heating. Check for
loose, broken, or corroded terminal connections.
J. Transistors and Integrated Circuits
Inspect for damage to body or case and for secure attachment to socket.
K. Terminal Connections, Soldered
(1) Inspect for cold soldered or rasin joints. Bad joints can be·
recognized by a dull, porous appearance.
(2) Check for excessive solder, insufficient solder, or solder
splashes resulting
from a previous repair.
(3) Check for corrosion at the terminal connections.
L. Rotary Switches
Check for proper mechanical operation; no binding or looseness should
be evident.
M. Printed Circuit Boards
Inspect for loose, broken or corroded terminal connections and damage
such as cracks, burns or charred track. Also, check for insufficient
solder, proper binding, fungus, mold or other deposits that should be
repaired.
N. Cathode-Ray Tube
Inspect tube face for burned spots or ether discrepancies which could
cause deterioration of the display.
Check tube for secure mounting.
O. CRT Fi lter
Check CRT filter for scratches or other blemishes which could cause
deterioration of the display.
1.B. 21400C
PART 4
5-2
Jun/84
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~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-2025B MULTIFUNCTION COLOR INDICATOR
3. Cleaning
Perform a routine cleaning any time the radar indicator is removed from the
aircraft.
A. Recommended Cleaning Agents
Table 5-l lists the recommended cleaning agents to be used during
overhaul of the
IN-2025B.
TYPE
USED TO CLEAN
Denatured Alcohol
Exterior surfaces (except CRT filter)
and interior surfaces.
Isopropyl
Alcohol
Printed circuit boards.
Glass Cleaner
(Windex or
CRT filter.
or equivalent)
Recommended Cleaning Agents
Table 5-l
B. Recommended Cleaning Procedures
WARNING: GOGGLES ARE TO BE WORN WHEN USING PRESSURIZED AIR TO BLOW
OUST AND DIRT FROM EQUIPMENT. ALL PERSONNEL SHOULD BE
CLEARED FROM THE IMMEDIATE AREA.
WARNING: OPERATIONS INVOLVING THE USE OF A CLEANING SOLVENT SHOULD BE
PERFORMED UNDER A VENTILATED HOOD. AVOlD BREATHING SOLVENT
VAPOR AND FUMES; AVOlD CONTINUOUS CONTACT WITH THE SOLVENT.
CAUTION: USE ONLY RECOMMENDED CLEANING SOLVENTS ON ELECTRICAL PARTS.
MANY AVAILABLE CLEANING SOLVENTS CAN SOFTEN AND PERMANENTLY
DAMAGE INSULATING MATERIALS.
CAUTION: ALUMINUM ELECTROLYTIC CAPACITORS CAN BE DAMAGED BY
HALOGENATED HYDROCARBON SOLVENTS. BENDIX AVIONICS RECOMMENDS
11
lSOPROPYL ALCOHOL" AS A SAFE CLEANING SOLVENT FOR PRINTED
CIRCUIT BOARDS CONTAINING ALUMINUM ELECTROLYTIC CAPACITORS.
OTHER SOLVENTS WHICH MAY BE USED ARE AS FOLLOWS:
I.B. 21400C 5-3
PART 4 Jun/84
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3.B.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-2025B MULTIFUNCTION COLOR INDICATOR
SAFE SOLVENTS
XYLENE
ETHYL ALCOHOL
BUTYL ALCOHOL
METHYL ALCOHOL
PROPYL ALCOHOL
CALGONITE (A BRAND OF DETERGENT)
PRINTED CIRCUIT BOARDS CONTAINING ALUMINUM ELECTROLYTIC
CAPACITORS SHALL NOT BE CLEANED WITH THE FOLLOWING SOLVENTS:
UNSAFE SOLVENTS
FREON TF, TMC
CARBON TETRACHLORIDE
CHLOROFORM
TRICHLOROETHYLENE
TRICHLOROETHANE
ALL (A BRAND OF DETERGENT)
METHYLENE CHLORIDE
(1) Perform exterior cleaning as follows:
(a) Wipe dust caver and exterior of chassis with a lint-free
elath dampened with denatured alcohol.
(b)
Use a clean camel's hair (or equivalent) brush saturated with
denatured alcohol
ta remove any foreign matter from rear
connecter.
(c)
Clean CRT filter with a lint-free elath slightly dampened
with Windex glass cleaner.
(d) Open any blocked ventilation hales in the dust caver by first
saturating the debris clogging the apertures with denatured
alcohol
and then blowing the loosened material out with an
air stream.
(2) Perform interior chassis cleaning as follows:
I .B. 21400C
PART 4
CAUTION: AVOlD AIR-BLASTING DELICATE PARTS.
(a) Remove dust and other dirt from all surfaces, including parts
and wiring, using a soft bristle, camel's hair (or
equivalent) brush
in conjunction with a clean, dry air jet
(25 to 38 psi).
5-4
Jun/84
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1
BENDIX/KING
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
(b) Any dirt that cannat be removed in previous step should be
removed using a soft bristle, camel's hair brush saturated
with isopropyl alcohol.
Use a clean, dry air jet (25 ta
38 psi) ta remove excess isopropyl alcohol and loosened
dirt.
(3) Perform printed circuit board cleaning as follows:
CAUTION: AVOlD AIR-8LASTING DELICATE PARTS.
{a) Remove dust and other dirt from board surfaces and
components using a soft bristle, camel's hair {or
equivalent) brush in conjunction with a clean, dry air jet
{25 ta 38 psi).
{b) Any dirt that cannet be removed in previous step should be
removed using a soft bristle, camel hair (or equivalent)
brush saturated with isopropyl alcohol. Use a clean, dry
air jet (25 to 38 psi) to remove excess isopropyl alcohol
and loosened dirt.
{4) Perform connecter cleaning as follows:
4. Repair
(a) Wipe dust and dirt from bodies, shells and cable clamps
using lint-free cloth moistened with denatured alcohol.
(b) Wipe dry with a clean, dry, lint-free elath.
(c) Remove dirt and lubricant from inserts, insulation and
terminals using soft bristle, camel's hair {or equivalent)
brush saturated with denatured alcohol.
(d) Ory insert with clean, dry air jet (25 ta 38 psi).
WARNING: VOLTAGE DANGEROUS TO LIFE EXISTS. REMOVE ALL POWER TO
INDICATOR 8EFORE PROCEED WITH REPAIR.
A. Repair Precautions
(1) Refer ta paragraph 4.8. for special ESDS handling precautions.
(2) Perform repairs and replace components with power disconnected
from the equipment.
(3) Use a conductive table top for repairs and connect the table ta
the ground conductor of the 60-Hz power line.
{4) Replace connectors, coaxial cable, shielded conductors, and
twisted pairs ONLY with identical items.
1.8. 21400C
PART 4
5-5
Dec/92
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BENDIX/KING
MAINTENANCE MANUAL
IN-2025B MULTIFUNCTION COLOR INDICATOR
(5) Reference ta "component side" of a printed circuit board in
this manual means the side on which the components are located;
"track side" refers
ta the other side.
(6) When repairing circuits, carefully observe lead dress and
component orientation. Keep leads as short as possible and
observe correct repair techniques.
(7) Observe cable routing throughout instrument assembly, prior to
disassembly,
ta enable a proper reinstallation of the cabling
during reassembly procedures.
B. Electrostatic Discharge Sensitive (ESDS) Deviees
Deviees
sensitive to electrostatic discharge are used in this
equipment. These deviees, including Metal Oxide Semiconductors
(MOS), sorne metal film resistors, and ether deviees, are susceptible
to
damage by electrostatic charges or high-voltage fields. Because
of the very high resistances in ESDS deviees, they can be damaged by
electrical sources that cannat deliver enough current ta damage
conventional semiconductors. Therefore, special precautions must be
taken during handling and rep~ir procedures to prevent damaging the
deviee.
The most common low-energy source causing damage to ESDS
deviees is the human body, which generates and retains static
electricity, in conjunction with nonconductive garments and floor
covering.
An individual can easily develop several thousand volts
of
electrostatic charge while simply walking across the floor or
moving around in a chair. Electrostatic charges of 20 kV have been
measured on personnel, and 35 kV has been measured on their
garments.
The capacitive elements in all MOS deviees can be destroyed by a
voltage
field, even when assembled into the circuit. Similar
capacitive elements in
linear integrated circuits, hybrids, and in
bipolar integrated
circuits are also susceptible ta field voltages.
Not all electrostatic damage will result in immediate catastrophic
failure. Damaged deviees may remain operating within the minimum
limits but could experience early field failure or erratic
performance.
The following precautions are recommended for ESDS circuits and are
especially important
in low humidity or dry conditions when
electrostatic problems are more prevalent.
CAUTION: ESDS DEVICES INCLUDE, BUT ARE NOT LIMITED TO, C-MOS,
J-MOS, PMOS, NMOS, SOCMOS, HMOS, MOS/FET, MICROWAVE MIXER
DIODES, SOME BIPOLAR DEVICES, AND SOME METAL FILM
RESISTORS.
I.B. 21400C 5-6
PART 4 Dec/92
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BENDIX/KING
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
(1) Storage
Store and transport all ESDS deviees in conductive material.
Do not insert ESDS deviees into conventional plastic "snow" or
plastic trays used for storing and transporting standard
semiconductor deviees. Special
bags or containers must have a
maximum resistivity of 10 ohms/cm, or the leads of the deviee
must be shorted together through a conductive material (special
foam) having a maximum resistivity of 10
4
ohms/cm.
Modules, circuit boards, or assemblies containing ESDS deviees
must be stored in static shielding bags with a maximum
resistivity of 10
4
ohms/cm on the outer layer of the bag, and
10
12
ohms/cm resistivity in the inner layer.
A caution label shall
be attached to the outside of all
containers containing ESDS deviees. The ESDS labels are
identified
in the advisory information located in the front of
this manual. Do not remove deviee from container until
actually used or tested.
(2) Work Station
1.8. 21400C
PART 4
All equipment, tools, materials, and personnel at the work
station must be maintained at the same electrical potential.
All grounding connections shall have common point, and that
point shall
be connected to electrical ground.
Soldering irons shall
be isolated from the power line by
transformer, or shall be direct current isolated. The
soldering iron must be grounded and have a resistance of less
than 0.2
ohm from the tip to ground when the iron is hot.
Test
equipment shall have all exposed metallic surfaces
electrically connected to the test equipment power system
ground (through 200 ohms or less).
Do not use rubber mats, carpets, and rugs in the work station
area.
Use grounded conductive mats.
Do not allow nonconductive items on the workbench. This
includes such items as plastic ash trays, cellophane wrappers,
plastic tools, styrofoam coffee cups, etc.
Maintain the relative
humidity higher than 40 percent (minimum)
in the work area.
Keep all material and work surfaces CLEAN in the work area.
Wash with damp cloth when necessary.
5-7
Dec/92
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BENDIX/KING
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Keep the work station static-safe. Periodically check the area
with a static meter. When a dangerous reading is observed,
remove the nonconductor or take precautions to prevent contact
with ESDS deviees.
(3) Personne 1
When handling electrostatic discharge sensitive deviees or
assemblies, wear a skin-contact wrist strap connected to the
work station common ground.
WARNING: DO NOT CONNECT PERSONNEL DIRECTLY TO EARTH OR
BUILDING GROUND. COMMERCIAL GROUNDING STRAPS
CONTAIN AN INTERNAL RESISTANCE OF ABOUT ONE MEGOHM
IN THE CORD TO BLEED THE ELECTROSTATIC CHARGE FROM
THE BODY WHILE PROTECTING PERSONNEL FROM ELECTRICAL
SHOCK.
DO NOT WEAR GROUND STRAP WHEN TROUBLESHOOTING OR
TESTING HIGH VOLTAGE CIRCUITS WITH POWER APPLIED.
Do not wear smocks, gloves, finger cots, or sleeve protectors
made of plastic, nylon, or rubber in the area where ESDS
deviees are handled.
When the operator is properly grounded, contact with the
operator's
hand will provide sufficient ground for hand tools
or ether tools that may be electrically isolated from ground.
(4) Special Troubleshooting Precautions
In addition to the above considerations, the following specifie
precautions should be observed when troubleshooting or
repairing
modules containing ESDS deviees.
Do not use high velocity dry air for applying heat during
troubleshooting. Special infrared heat deviees should
be used.
Do not use Freon spray during troubleshooting. To cool
components, use antistatic quick-chill sprays.
Remember, even when the ESDS deviee is installed on a printed
circuit board it can STILL be damaged by electrostatic
discharge.
C. General Repair and Replacement Procedures
The repair or replacement of worn, damaged or defective parts
involves standard repair techniques.
1
1.8. 21400C
PART 4 5-8
Dec/92
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BENDIX/KING
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Make a wiring diagram or sketch before removal of any part requ1r1ng
unsoldering
of several lead wires. Show color coding or wire
marking and the approximate location and identify of the terminals
to which the wires are connected. Also, show where lacing is
removed or where dress is important.
Whenever maintenance is performed on the chassis cabling, make
continuity checks throughout the cable to check that the cable is
still wired correctly. Refer to the main frame schematic diagram
shown in figure 7-1.
NOTE: Always add a small amount of rosin flux or rosin-core
solder while resoldering connections.
After replacing or repairing
any printed circuit board or assembly,
perform the functional test in PART 3 of this manual to determine
proper operation of the repaired unit.
O. Replacing Resistors, Capacitors and Diodes
(1} Before removing diodes or polarized capacitors (electrolytics},
note polarity markings and orientation on circuit board.
(2} Using a small cutting tool (small diagonal cutter}, carefully
eut
off both component leads, leaving about 1/16 inch of lead
protruding
from circuit board. Remove component.
(3}
1
1.8. 21400C
PART 4
NOTE: If desired to disconnect only one lead for component
substitution (such as may be required during
troubleshooting}, refer to paragraph 4.0.(5}.
CAUTION: DO NOT APPLY HEAT AT A PLATED-THRU-HOLE FOR MORE
THAN 8 SECONDS. USE 20 TO 50 WATT SOLDERING IRON
ONLY.
Grasp a eut off lead (on component side of board} with small
needle-nosed pliers. Apply soldering iron (with a little flux
on the tip) to circuit board where lead passes through circuit
board. Track side can also be used. If track side is used for
unsoldering, ensure that the correct lead
and circuit board
point is located. As soon as solder melts, carefully remove
cutoff lead from component side. If excessive force is
applied, the plated-thru-hole may be pulled out of the board
with the lead.
5-8.1
Dec/92
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BENDIX/KING
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
(4) Using soldering iron, reheat point on circuit board from which
a lead has been removed. When remaining solder melts, apply
and actuate solder sucker to remove solder. Repeat for
remaining lead. Use solder sucker as required until hales in
board are clean (as indicated by no solder on the walls, top,
or bottom of the hales in the circuit board).
NOTE: Final cleaning (in the circuit board) will be done just
prior to installing new component.
(5) If only one lead is being disconnected, for component
substitution during troubleshooting, proceed as follows:
1
1.8. 21400C
PART 4
(a) From component side, grasp lead close to circuit board
with small needle-nosed pliers.
(b) From track side of circuit board, heat point on circuit
board where lead passes through board. When solder melts,
carefully
lift lead upward until lead has cleared circuit
board.
(c) Repeat paragraph 4.0.(4} and ensure that all solder is
removed from hale.
5-8.2
Dec/92
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4.0. (5)
(d)
~ General Aviation
._..- Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Replace lead as instructed in procedures in paragraph
4.0.{13).
NOTE: Do not bend or crimp component leads ta hold component
in position prior to soldering. It is recommended
that component leads remain straight when protruding
through board.
Keeping the leads straight makes
component replacement easier and prevents damage to
the
circuit board when removing components.
(6) Bend leads of new component sa that component fits freely into
hales in
circuit board.
(7) If component has polarity markings (electrolytics, diodes), ensure
that
component is oriented the same as the removed component.
Insert new component through hales in circuit board. Ensure that
component is flush with circuit board or is in the same position
as the removed component.
(8) Use flux and solder sparingly and solder the component to circuit
board from the track side of the board. Do not use excessive
heat.
Ensure that position of component does not change during
soldering.
(9) Carefully inspect solder joints ta ensure that excess solder has
not been used and that no short circuits are in evidence. Solder
should fill the circuit board hale through which the component
lead is inserted.
(10) Using small diagonal cutters or end nippers, snip excess leads
from components.
(11) If more than one component is being replaced, repeat the above
paragraphs for each component.
(12) When all components have been replaced, use a small brush or pipe
cleaner
and solvent to clean new solder joints. Ensure that all
flux
and solder rasin is removed. Use a round toothpick to help
remove heavy deposits of rasin. Solder joints should be smooth,
bright, and clean when properly soldered and cleaned.
(13) Replace single lead (from component on which one lead was lifted
for substitution) by inserting lead through hale in circuit board
and resoldering to board. Use flux and solder sparingly.
I.B. 21400C
PART 4
5-9
Jun/84
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4.
E.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Replacing Semiconductors on Printed Circuit Boards
Never remove or install a semiconductor deviee with the supply voltage
turned on. Plugging-in or
removing a transistor can produce voltage
transients that might damage the deviee.
When removing or installing soldered-in diodes, always apply a heat
sink between semiconducting body and solder terminal or standoff. The
heat sink will dissipate heat from soldering iron and prevent diode
from being damaged. Always use a law wattage soldering iron and apply
heat only
long enough to make a good solder joint.
CAUTION: DO NOT REMOVE HEAT SINK UNTIL SOLDER JOINT HAS COOLEO.
(1) Note tab location, lead spacing, or lead numbers before
proceeding.
(2)
Grasp the component with two fingers and alternately apply
soldering iron with a
little flux on the tip ta each component
lead, rocking component as each lead becomes unsoldered. Do not
overheat
circuit board. Repeat, alternately heating leads and
rocking component until component is removed.
NOTE: Acup-shaped desoldering tip can be used with advantage,
simultaneously unsoldering
all leads.
(3) Reheat
each point on circuit board from which a lead has been
removed. When remaining solder melts, use solder sucker as
required until hales in board are clean (as indicated by no solder
on the walls, top, or bottom of the hales in the circuit board).
(4)
Using solvent and pipe cleaner tip, carefully scrub bath sides of
the
circuit board (hales, pads, etc.) from which component was
removed.
(5) Insert new component into hales on circuit board ensuring that
component orientation (transistor tab, etc.) is same as the
component that was removed. Ensure that component height above
(or flush with) circuit board is same as component height that was
removed.
NOTE: Do not bend or crimp component leads to hold component in
position
prier to soldering. It is recommended that
component leads remain straight when protruding through
board.
Keeping the leads straight makes component
replacement easier and prevents damage to the circuit board
when removing components.
I.B. 21400C 5-10
PART 4 Jun/84
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4.E.
(6)
(7)
(8)
(9)
(10)
General Aviation
Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Use flux and solder sparingly. Solder component to printed
circuit board from track side of board. Do not use excessive heat
and ensure that the position of component does not change during
soldering.
Carefully inspect solder
joints to ensure excess solder has not
been used and that no short circuits are in evidence. Solder
should fill the circuit board hole through which the component
lead is inserted.
Using small diagonal cutters or end nippers, snip excess leads
from components.
If more than one component is being replaced, repeat the preceding
procedures for
each component.
When all components have been replaced, use a small brush or pipe
cleaner
and solvent to clean new solder joints. Ensure that all
flux
and solder rosin is removed. Use a round toothpick to help
remove heavy deposits of rosin. Solder joints should be smooth,
bright,
and clean when properly soldered and cleaned.
F. Replacing Power Transistors
(1) Unsolder leads and remove attaching hardware. Remove transistor
and insulator.
NOTE: A plastic insulator covers each power transistor on the
rear heatsink.
Using a small needle nose pliers, pull out
the
plastic plugs covering the transistor mounting screws,
and unscrew the mounting screws.
(2) Apply Thermal Joint Compound Type 120 (Wakefield Engineering,
Inc.} to
mounting surface of transistor insulator and to mounting
surface of replacement transistor.
(3) Reinstall transistor insulator and power transistor using hardware
removed in step (1).
NOTE: Electrical contact to the transistor case is made through
the
mounting hardware on sorne power transistors. Always
reinstall the original hardware. Do not omit washers and
spacers. Torque the mounting screws to 3-to-6 inch pounds.
(4) After installing replacement transistor, but before making any
electrical connections, measure resistance between case of
transistor and the chassis to ensure that insulation is effective.
The resistance measured should be greater than 10 megohms.
(5) Reconnect leads to transistor and solder in place.
I.B.
21400C 5-11
PART 4 Jun/84
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4.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INOICATOR
G. Replacing Multi-Lead Components (IC's, etc)
(1) Preferred Method
(a) Remove component by clipping each lead along both sides.
Clip off leads as close to the component as possible.
Oiscard component.
(b) Heat hole from track side and remove clipped lead from each
ho le.
(c) Melt the solder in each hole and, using a desoldering suction
tool,
remove solder from each hale.
(d) Insert replacement component observing correct orientation.
CAUTION: AVOlD USE OF EXCESSIVE HEAT.
(e) Solder component in place from the track side of the board.
Avoid solder runs. No solder is required on contacts where
no track exists.
(2) Optional Method
With a Pace Madel PRC-150 Bench-Top Repair Center (Silver Spring,
Maryland), any multi-lead component can be quickly and easily
removed without damaging the component or the PC board.
H. Wiring Repairs
NOTE: When necessary to disturb the dress of the wires, carefully
ensure that the original dress is maintained
when replacing
wires.
Replace damaged wiring with same size wire and color code. Ensure that
no bare wires are touching chassis, other bare wires, metal cases, or
ether parts.
If wire is being removed from a terminal or component, tag wire to
prevent incorrect connections.
I. Replacing
Ribbon Cables and Connectors
The connectors attached to the ribbon cables are not repairable. The
cable and the connecter are a molded assembly. Replace the cable
assembly with the proper part number listed in Section VI.
I.B. 21400C
PART 4
5-12
Jun/84
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4.H.
J.
~ General Aviation
._.- Avionics Division
MAINTENANCE MANUAL
IN-20256 MULTIFUNCTION COLOR INDICATOR
Replacing Cathode-R~ Tube
If the cathode-ray tube is found defective, replace CRT using,procedure
recommended in paragraph S.M. After replacement, perform the Overall
CRT Alignment procedure given in Section IV.
K. High-Voltage Power Supply
If the high-voltage power supply module is found defective, replace
this molded component. After replacement, perform the High Voltage
Power Supply adjustment and the Overall CRT Alignment located in
Section IV of this manual.
5. Disassembly/Assembly
This paragraph provides disassembly instructions for the IN-20256 Radar
Indicator. Many disassembly procedures contain an item number reference in
parentheses following the part noun name in the procedure. These item
numbers apply to figure 6-1 PART 4, Parts List.
WARNING: VOLTAGE DANGEROUS TO LIFE EXISTS IN THIS EQUIPMENT. REMOVE ALL
POWER FROM THE EQUIPMENT BEFORE PROCEEDING.
NOTE: References to left side and right side in the following procedures
refers to your
left or right side when looking at the front panel.
Assembly is in the reverse arder of disassembly unless otherwise
specified.
A. Oust Caver Removal
(1} Loosen the two screws in the slotted hales, one on each side near
the
front.
(2) Release the two quarter-turn fasteners on the rear, near each
si de.
(3) Slide the dust caver (2) off the rear.
B. Display Board and Processor Board Removal
(1) Remove the dust caver (reference paragraph S.A.}.
(2) Locate the display board (166) and processor board (170} on the
right side.
NOTE: The processor board is attached to the solder side of the
display
board with six screws and two ribbon cables. The
two boards are removed together from the frame and then
separated
if desired.
I.B. 21400C 5-13
PART 4 Jun/84
The document reference is online, please check the correspondence between the online documentation and the printed version.

5.B.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-2025B MULTIFUNCTION COLOR INOICATOR
{3) There are 11 screws visible on the display board. Only five
screws hold the boards to the frame. The other six screws hold
the processor board to the display board. Refer to figure 5-1 and
remove the five screws and washers holding the display board.
D
SCIEIS "A" HOLD THE IOAID TO TKE FIAME.
&3109341
Display Board Removal
Figure 5-1
A
(4) Tilt the top of the boards away from the frame, lift the boards
away from the frame, and lay the boards flat on the bench.
{5) Unplug the two ribbon cable connectors {P1024 and Pl026) from the
bottom edge of the display board.
(6) Unplug the ribbon cable connector (P1023) from the bottom edge of
the processor board.
(7) Remove the display board (with processor board attached) from the
frame.
{8) To separate the two boards, remove the six screws (171) and
washers holding them together and unplug· the two ribbon cable
connectors
(P2022 and P2029) located along the top edge of the
processor board.
1.B. 21400C
PART 4 5-14
Jun/84
The document reference is online, please check the correspondence between the online documentation and the printed version.

5.
~ General Aviation
~ Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
C. Master/Slave Data Board Removal
(1) Remove the dust caver (reference paragraph S.A.).
(2)
Locate the master/slave data board (7S) on the left side.
(3) Remove the five screws (76) and washers holding the board on the
frame.
(4) Tilt the top of the board away from the frame and lay the board on
the bench.
(5) Unplug the ribbon cable connecter (P1111) located near the bottom
edge and remove the board from the indicator.
D. Memory Board Removal
(1) Remove the dust caver (reference paragraph S.A.).
(2) Place the indicator on its top.
(3) Locate the memory board (79) on the bottom of the indicator.
NOTE: The memory board is attached by four 5/8-inch-long screws
which pass through bushings on the interconnect board and
are threaded into the mounting plate in the HV power supply
assembly.
(4) Remove the four 5/8-inch screws (80) and washers securing the
memory board.
(5)
Lift the rear edge of the memory board away from the indicator.
(6) Unplug the ribbon cable connecter (P6009) from interconnect board,
near the front edge, and remove the memory board. The ribbon
cable
is soldered to the memory board.
E. Sweep Board Removal
(1) Remove the dust caver (reference paragraph S.A.).
(2) Locate the sweep board (143) on the top.
(3) Remove the four screws (144) and washers holding the board on the
main frame.
(4) From the rear, remove the three flat-head screws (147) holding the
board-mounted heatsink ta the rear panel (128).
I.B.
21400C S-15
PART 4 Jun/84
The document reference is online, please check the correspondence between the online documentation and the printed version.

S.E.
(S)
(6)
~ General Aviation
._..- Avionics Division
MAINTENANCE MANUAL
IN-202SB MULTIFUNCTION COLOR INDICATOR
Carefully lift up the right side of the sweep board from the main
frame ta reach the cable connectors on the underneath side.
Carefully disconnect the five cable connectors
(P1002, P1021,
P1022, P1414, and P1013) from the sweep board, and remove the
board from the indicator.
F. Rear Panel and Rear Connecter Board Removal
NOTE: The rear panel (128) and the rear connecter board (118) are
constructed
as an assembly (116) and are easily removed as a
single unit.
(1) Remove the dust caver (reference paragraph S.A.).
(2) On the rear panel, remove the five flat-head screws (147) along
the
top edge.
NOTE: The three centermost screws attach ta the heatsi~k on the
sweep board.
(3) On the rear panel, remove the flat-head screws (117) from the two
bottom corners.
NOTE: Before proceeding, observe the location of the sponge
located between the rear connecter board and the "T" board
(198).
The sponge must be replaced in the same position.
(4) Carefully
tilt the top of the rear panel away from the frame.
(5)
Unplug the 20-pin ribbon cable connecter (Pl006) from the rear
connecter board. The connecter is located along the side of the
board.
(6) Unplug the 2-wire connecter (P1019) from the rear connecter board.
This cable connects to the neck coil on the CRT.
(7) Unplug the 40-pin ribbon cable connecter (P1007) from the bottom
edge of the rear connecter board.
NOTE: This cable can also be unplugged from the interconnect
board (Pl008).
(8) Unplug the 4-pin connecter PSOOS from the rear connecter board.
This connecter has two wires attached which may also be unplugged
from the interconnect board {P5001).
(9) The rear panel assembly is still attached by a ground wire to the
"T
11
board on the CRT socket. Carefu lly pu 11 the grou nd wi re from
the push-on pin located near the bottom edge of the .. T .. board.
Refer to figure 5-2.
I.B.
21400C 5-16
PART 4 Jun/84
The document reference is online, please check the correspondence between the online documentation and the printed version.

ÂLILIEI) Bendix
~ Aerospace
Bendix General Aviation
Avionics Division
S.F.
MAINTENANCE MANUAL
IN-2025B MULTIFUNCTION COLOR INDICATOR
(10) Remove the rear panel and connecter board assembly.
NOTE: Completely removing the rear panel from the connecter board
requires unsoldering the items mounted on the rear panel
(heatsink), or unmounting them. However, the panel and
connecter board may be partially separated for service as
follows.
(11)
On the rear panel, remove the four flat-head screws around P5005,
and remove the four flat-head screws around P5004.
(12) Observe the two slots in the top edge of the rear panel. Remove
the flat-head screw located near the bottom of each slot. A
eut-out in the black heatsink
is provided for access to the
screws.
(13) Pivot the
bottom of the connector board away from the rear panel
to obtain access to the other side. Be careful to avoid breaking
the wires soldered to the board.
(14) When replacing the rear panel assembly, it may be necessary to
unp 1 ug the
11
T" board when reconnecti ng the pus h-on whi te-b 1 ack
ground wire to the "T" board. Be sure to replace the sponge
between the "T" board and the connec tor board.
NOTE: The small two-wire connector (P1019) from the CRT neck coil
(192) is not keyed, but is wired so it may be installed in
any position. Polarity does not have to be considered when
plugging the connector onto the board.
G. Removi ng the "T
11
Board
(1) Remove the dust caver (reference paragraph S.A.).
(2) Refer to steps (2) through (9) in paragraph 5.F., and remove the
rear
panel assembly.
NOTE: It is not necessary to separate the rear panel from the
rear connector board.
(3) Locate the
"T" board plugged onto the CRT base.
NOTE: The "T
11
board contains the socket (XV 1001) for the CRT.
(4) Carefully pull the "T" board straight back and unplug it from the
CRT.
I.B. 21400C 5-17
PART 4 Mar/86
The document reference is online, please check the correspondence between the online documentation and the printed version.

5.G.
(5)
~ General Aviation
_..- Avionics Division
MAINTENANCE MANUAL
IN-20258 MULTIFUNCTION COLOR INDICATOR
Observe that there are three wires with push-on pins, one two-wire
connecter,
and one ribbon cable connecter plugged into the
11
T
11
board.
CAUTION: The three push-on pins on the
11
T
11
board are not keyed,
but the wires are color coded.
They must be connected
to the proper pins. Refer to figure 5-2.
(6) Unplug the three wires connected to the
11
T" board with push-on
pins at El, E2, E3. Refer to figure 5-2.
(7) Unplug connectors Pl020 and Pl415 from the np board, and remove
the board.
(8)
When replacing the "T
11
board, refer to figure 5-2 for board
orientation
and location of the three wires with push-on connecter
pins. Also, observe
that the two-wire connecter (P1415) has four
pins
and may be plugged into the board without concern for key
positions.
CAUTION: Don•t forget to properly position the sponge between the
"T" board and the rear connecter board before installing
the rear panel assembly.
VIOLET WIRE
TO POWER
SUPPLY
HOOULE Al
A3613718
·.
·· ....
..........
··.
,.------,
1 1
1 1
L-- ---..1
WHT-BLK WIRE
(GND) TO REAR
COHNECTOR ~D
Pl020 TO
SWEEP BOARD
CRT
SOCKET
XVlOOl
Pl415
2 WIRES
TO POWER
SUPPLY
BLACK OR RED
WIRE TO POWER
SUPPL Y HOOULE Al
Connections to
11
T
11
Board, Rear View
Figure 5-2
I.B.
21400C
PART 4 5-18
Jun/84
. : .
The document reference is online, please check the correspondence between the online documentation and the printed version.