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SOLDERING
Use care when mounting all components.
Use only rosin core solder (acid core solder is never
used in electronics work). A proper solder joint has just enough solder to cover the round solder-
ing pad and about 1/16 inch of the lead passing through it.
There are two improper connections to
beware of: Using too little solder will sometimes result in a connection which appears to be soldered
but actually there is a layer of flux insulating the component lead from the solder beado This situatloll
can be cured by re-heating the joint and applying more solder.
If too much solder is used on a joint
there is the danger that a conducting bridge of excess solder will flow between adjacent circuit board
conductors forming a short circuit.
Unintentional solder bridges can be cleaned off by holding the
board up-side down and flowing the excess solder off onto a clean hot soldering iron®
Select a soldering iron with a small tip and a power rating not more than 35 watts.
Soldering guns
are completely unacceptal]le for assembling transistorized equipment because the large magnetic
field they generate can damage solid state components.
CIRCUIT BOARD ASSEMBLY
( )
Prepare the circuit board for assembly by thoroughly cleaning the conductor side with a
scouring cleanser.
Rinse the board with clear water and dry completely.
Solder each of the fixed resistors in place following the parts placement designators printed on the
circuit board and the assembly drawing figure 1. Note that the fixed resistors are non-polarized
and may be mounted with either of their two leads in either of the holes provided®
Cinch the resis-
tors in place prior to soldering by puttirlg their leads through the holes and pushing them firmly
against the board, on the conductor side of the board bend the leads outward to about a 45° angle.
Clip off each lead flush with the solder joint as the joint is made.
A
P
i
silverorgold-disregardthisband
R2
R3
R4
R5
R6
R7
R9
R10
Rll
R12
R13
R14
R16
R17
R18
R19
R20
R21
R23
R24
R25
R26
R27
R28
R30
R31
R33
R34
COLOR CODE A-B-C
.
red-red-yellow
.
yellow-violet-yellow
.
yellow-violet-yellow
..
yellow-violet-yellow
..
yellow-violet-yellow
..
red-red-yellow
.
red-red-yellow
..
yellow-violet-yellow
.
yellow-violet-yellow
..
yellow-violet-yellow
..
yellow-violet-yellow
.
red-red-yellow
..
red-red-yellow
..
yellow-violet-yellow
..
yellow-violet-yellow
.
yellow-violet-yellow
•.
yellow-violet-yellow
..
red-red-yellow
..
red-red-yellow
.
yellow-violet-yellow
..
yellow-violet-yellow
..
yellow-violet-yellow
..
yellow-violet-yellow
.
red-red-yellow
.
brown-green-yellow
.
brown-green-yellow
.
yellow-violet-brown
..
yellow-violet-brown
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Figure 1
Install the ceramic disk capacitors. Their value is marked on the body of the part.
DE SIC NAT ION
VA LUE
()C5
()C6
15 pf.
15 pf.
Up to this point all components have been non polarized and either lead could be placed in either of the
holes provided without affecting the operation of the circuit.
Electrolytic capacitors are polarized and
must be mounted so that the " + " lead of the capacitor goes through the " +" hole in the circuit board.
In the event that the "-" lead of the capacitor is marked rather than the " +" lead it is to go through the
unmarked hole in the circuit board.
Note that the operating voltage (v. ) specified for a capacitor is the minimum acceptable rating.
Capaci-
tors supplied with specific kits may have a higher voltage rating that that specified and may be used
despite this difference.
For instance. a 100 mfd. 25v. capacitor may be used in place of a 100 mfd. 16v.
capacitor without affecting the operation of the circuit.
Mount the following electrolytic capacitors and solder them in place.
The values, voltage rating and
polarization are marked on the body Of the part.
DE SIC NATIO N
D E SC IH PT ION
100 mfd. 16v.
100 mfd. 16v.
2. 2 mfd. 6v.
2. 2 mfd. 6v.
Mount the integrated circuits.
Note that the orientation of these parts is keyed by a notch at one end
of the case which aligns with the semi-circular key on the designator printed on the circuit board.
Use particular care when installing these parts, like any other semi-conductor they are heat sensitive
and should not be exposed to extraordinarily high soldering temperatures.
Make sure that the orient-
ation is correct before soldering, once the unit is in place it cannot be removed without destroying it.
DESIGNATION
TYPE NO.
(
)
IC-1
........................
748typeop-amp
(
)
IC-2
........................
748typeop-amp
In the following steps 4 shielded cable harnesses will be built up for use in later assembly steps.
These harnesses are assembled at this time so that full lengths of wire in three different colors
are available.
Be sure to use three different colors in each harness to ease identification of the
wires during installation. See figure 2.
( )
Cut four 4 inch lengths of one color insulated wire.
Strip 1/4 inch of insulation from each
end of each wire and twist the exposed strands tightly together.
''Tin" the exposed strands
by melting a small amount of solder into the wire.
( )
Cut four 4 inch length of a second color insulated wire.
Strip 1/4 inch of insulation from
each end of each wire and twist and tin the exposed strands.
Cut four 2-1/2 inch lengths of a third color insulated wire.
Strip 1/4 inch of insulation
from each end of each wire and twist and tin the exposed strands.
Prepare four 3 inch lengths of the flat ribbon braid supplied by inserting a pencil to
spread the braid into a tube 2-1/2 inches long.
With the pencil still in place twist one
end of the tube to a point and solder the strands at the point together.
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