Heathkit HW-12 - Page 11

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Before attempting any work on the circuit
board, read the following instructions carefully
and study the Figures, It is only necessary to
observe the following basic precautions to insure
proper operation of the unit the first time it is
turned on,
Proper mounting of components on the board is
essential for good performance, A good general
rule to follow is that all components on the
board should be mounted tightly to the board,
unless instructions state otherwise, All leads
should be kept as short as possible to mini-
mize the effects of stray capacity in the wiring,
Proper and improper methods of mounting are
illustrated in the accompanying Figures,
amin: can
va ob iy SEND LEAD
H CLOSE TO
1 BODY
4
SPREAD. LEADS OF EACH COMPONENT
TO KEEP THEM FROM FALLING OUT
WHEN THE BOARD IS TURNED OVER
NOTE: Exercise care not to damage resistors
or capacitors when bending the leads as shown
201 aris Ae wee Wal,
pacitors will generally fit in place with no lead
preparation other than determining that the
leads are straight. Components with lugs nor-
mally require no preparation unless the lugs
appear to be bent, in which case they can be
straightened with pliers.
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i= 2
zs ‘D =
ia iy
3
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Qe
p
in place, When ag
eae Pe ate ee t=) fat a
ui
The actual technique of soldering leads to a
circuit board is quite simple, Position the tip
of the soldering iron so that it firmly contacts
both the circuit board foil and the wire or lug
O{o
opps Ss
ONNECTION
to be soldered, as shown, The iron should be
held so that solder is not likely to flow to ad-
jacent foil conductors or connections. The solder
should immediately be placed between the iron
and the joint to be soldered, Remove the length
of solder as soon as its end begins to melt and
flow onto the lead and foil, Hold the tip of the
iron in place only until the solder begins to flow
outward over the foil; then remove the iron
quickly,
Avoid overheating the connection, A soldering
pencil or small iron (approximately 25 watts)
is ideai for use in circuit board work, If only
a high wattage iron or soldering gun is avail-
able, precautions must be taken to avoid circuit
board damage due to overheating and excess
solder,
SOLDER ON SOLDER ON LEAD WAS MOVED NO
LEAD ONLY FOIL ONLY BEFORE SOLDER LEAD
HARDENED
IMPROPER SOLDER CONNECTIONS
“SOLDER
AND LEAD BRIDGES
The use of excessive amount of solder will
increase the possibility of bridging between foil
conductors or plugging holes which are to be
left open for wires which may be added later
on. If solder is accidentally bridged across
insulating areas between conductors, it can be
cleaned off by heating the connection carefully
and quickly wiping or brushing the solder away
with a soft cloth or clean brush, Holes which
become plugged can be cleared by heating the
area immediately over the hole while gently
pushing the lead of a resistor through the hole
from the opposite side, and withdrawing the
lead before the solder rehardens, Do not force
the lead through; too much pressure before the
solder has time to soften may separate the
foil from the board.