TM 11-6720-242-35
(9) Check for a meter reading of -21 + 3 vdc
(4) Check for a maximum meter reading of 1
between pins 2A and 1C. Then check for a maximum
volt dc between pins C and D.
meter reading of 4 vac rms, between the same pins.
(5) Reset test fixture switch S2 to position 1
(10) Check for a meter reading of 24 + 5 vac
and adjust the current into pin P for a meter reading of
between pins 2C and 2A.
35 5 milliamperes. Then check the voltage across pins
C and D for a reading between 72 and 58 vdc. Check
(11) Check for a meter reading of 3.2 + 0.5
the voltage across pins N and D for a minimum reading
vdc between pins 2D and 1E.
of 0.15 vdc.
c. Testing Scan Heat Sink Assembly. Assemble
(6) Set test fixture switch S2 to position 2 and
the special test setup and connect it to the scan heat
switch S1 to position 2.
sink assembly as shown in figure 3-2. All measurements
CAUTION
NOTE
The voltage across pins A and D
When the designated value or
(ground) must never exceed +215
condition of the test is not obtained,
vdc.
trace the malfunctioning circuit in
(7) Adjust test set potentiometer to obtain a
figure 6-16 to isolate the faulty part
meter reading of 10 milliamperes. Check for a meter
or assembly for replacement.
reading between 180 and 210 vdc across pins A and D.
The pins designated in the following
Check for a reading that does not exceed 1.5 millivolts
procedure refer to the test fixture.
across pins N and D.
(1) The scan heat sink assembly must be
3-6. Isolating Trouble Within Stage
removed from the camera control with the wires still
When a trouble has been localized to a stage or a
circuit, use the following procedures to identify the
defective part.
connector removal.
a. Check the suspected transistor, or other
component in the circuit to which a trouble was
(2) Connect the heat sink connector to the
localized.
test set connector and energize the circuits with an input
of 115 5 vac, 400 Hz.
b. If a voltage reading was abnormal, make point-
(3) Set test set switch S2 to position 2 and
switch S1 to position 1.
Section II. REPAIRS AND ALIGNMENTS
3-7. General Parts Replacement Techniques
iron and the power source. Use longnosed pliers or
another form of heat sink between the solder joint and
a. With the exception of test points, electrical
the transistor.
contacts and the mating surface of connectors; the
wiring, assemblies and parts of the plug-in board
d. To remove a component from a printed circuit
assemblies are coated with an electrical insulating
board which is covered with an electrical insulating
compound designated as conformable coat per MIL-
compound coating, a soldering iron is applied to the
I46058, Type ER (FS10006). The replacement of an
point where the component is soldered to the board. The
assembly or part requires the removal of this coating
heat from the iron softens and penetrates the coating
and the procedure must be performed with care for the
and melts the solder, enabling the removal of the
protection of the board and the component. Refer to d
component. When the defective component has been
below for the type of coating and the solvent cleaner
replaced, it must be recovered with the insulating
that is used.
coating, the preparation of which is described below.
b. When replacing an assembly or part, note its
e. The materials required are PC12-007M (Part A)
orientation and identify the points of electrical
and PC12-007M (Part B), Hysol Corporation, Olean, N.
connections before removal.
Y.
WARNING
c. Use a pencil-type soldering iron with a
Avoid contact of the material with
maximum capacity of 25 watts for soldering and
skin or eyes. If contact with the eye
unsoldering electrical connections. If an ac voltage only
occurs,
is available to heat the soldering iron, ALIGNMENTS
Change 3 3-6