Do a Good Soldering Job. Poor soldering is the
greatest single cause of problems in completed
units. A large part of the soldering in this kit will
be done on printed circuit boards. This makes it
easy to do a professional-looking construction job.
To do the soldering in this kit you will need a
small pencil-type soldering iron. A 25 to 50 watt
iron is satisfactory.
To mount components on the circuit boards,
unless you are told to do otherwise, first bend the
leads to fit the holes in the board using your
longnose pliers. Next, pass the leads through the
holes and press the component down until it rests
squarely on the surface of the board. You may
bend the leads on the other side of the board
slightly outward so the component stays put when
you turn the board over for soldering.
To solder the component leads to the foil pads,
apply the tip of your iron so that it touches both
the lead and the foil. At the same time, feed the
end of the solder to the lead and the foil until a
small mound of molten solder surrounds the lead
and covers the pad. When this happens, withdraw
the solder, then the iron.
After the solder has solidified, clip off the lead
close to the solder mound with your diagonal
cutters. When soldering components on the circuit
boards, watch out for solder bridges that cause
short circuits. Each time you solder a connection.
make sure that the solder mound covers only that
connection and does not run over to a nearby pad
or foil path.
When you connect wires and componeuts to
terminal lugs, controls, and other parts of the
chassis, be sure the mechanical connection of the
*ire or lead to the terminal lug is secure before
you solder. Do this by hooking the wire or lead
througJr or around the terminal lug, and then crimp
it with your longnose pliers.
Each chassis wiring step will include a notation
such as (NS), (Sl), (S2), or (S3). These notations
tell you whether to solder the connection made in
that step and, if so, the total number of wires to be
connected at that point. Each time you make a
soldeq connection, check to see that you have the
correct number of wires connected to the terminal
lug. The r"rotation (NS) indicates that a connection
should not yet be soldered because other wires will
be added. When you install the last wire, you will
solder the terminal. This will be indicated by the
letter S followed by a number, as explained
previously. This number tells you how many leads
are supposed to be connected to the terminal
before it is soldered. For example, if a step says,
"Connect a wire to lug 6 (S3)," there should be
three leads connected to this terminal before it is
soldered. In cases where a wire or colrlponent lead
passes through a terminal or lug and connects to
another terminal or lug, it counts as two leads, one
entering and one leaving the terminal or lug.
As we stated before, poor soldering is the
greatest single cause of problems in equipment
returned to us for repair. You can greatly reduce
the possibility of poorly soldered cotrnections in
your receiver if you clean the leads on resistors and
capacitors before installing them. Do this by
scraping the leads lightly witir a knife. or twisting
them between two pieces of fine satrdpaper.
You can further guard against poor soldering
by using a clean, hot iron at all tirnes. Be sure that
enough heat is applied to the solder connection to
avoid rosin joints. This is of the tttmost impor-
tance! Another important point to remember is to
avoid using too much solder. Use onll' enortgh to
lightly cover the leads and termir-ral )'ou are
soldering. Let any excess solder florv onto the tip
of your iron and wipe it off with a ra-e. Big blobs of
solder on terminals or circuit board pads are almost
certain to result in trouble.
Finally, use only the solder sr.rpplied in this kit.
If you buy more solder locally, make sltre the
container is marked "rosilt-core solder." DO NOT
USE ACID.CORE SOLDER OR SOLDER PASTE
FLUX. If you use either of these, you rvill ruin
yotrr oscilloscope. lile cannot sen,ice artl' eqttip-
nlent on tvlticlt acid-core solder or solder paste .flux
lrus beert usecl.
Use the Figures. Pictorial diagrams throughout
this manttal shorv the placement of parts and the
details of construction steps. In some cases a part
may fit into position iu more than one rvay. only
one of which is correct. Study the figures carefully
and make sure that you know exactly hotl' a part is
to be mounted before proceeding. In some cases
the illustrations may be sligJrtly distorted to show
certain details. In most instances the illustrations in
this manual show all parts in proper perspective-
You are now ready to begin an exciting
project. The oscilloscope you are going to buiid is a
valuable test instrutnent that will give you many
years of service.
For this reason, we urge you to take yolr time
and do careftil work. Some students get impatient
to finish the oscilloscope quickly rvitirout read::g
l
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