Heathkit SW-7800 - Visual Checks

Heathkit
Page
111
IN
CASE
OF
DIFFICULTY
Begin
your
search
for
any
trouble
that
occurs
after
assembly
by
carefully following
the
steps
listed
below
under
“Visual
Checks.”
After
you
complete
the
“Visual
Checks,”
refer
to
the
“Troubleshooting
Charts.”
Start
with
the
chart labeled
“General Prob-
lems”
and
locate
your
problem
in
the
left
column
of
this
chart.
The
right
column
of
the chart shows
you
which
components
could
be
at
fault and
may
give
you
typical
voltage
indications
on
a
specific
component.
This
chart
may
also
direct
you
to
another chart that
deals
with
a
specific
circuit
board
Refer
to
the “Circuit
Board
X-Ray
Views” for
the
physical
locations
of
parts
on
the
circuit
boards.
VISUAL
CHECKS
1.
Recheck
the
wiring.
Trace
each lead with
a
colored
pencil
on
the
Pictorial
as
you
check
it.
It
is
frequently helpful
to
have
a
friend
check
your
work.
Someone
who
is
not
famil-
iar
with
the
unit
may
notice something
that
you
have
consistently
overlooked
2,
About
90%
of
the
kits
that
are
returned
to
the
Heath
Company
for
repair
do
not
function
properly
due
to
poor
connections
and
solder
ing.
Therefore,
you
can
eliminate
many
troubles
by
reheating
all
of
your
connections
to
make
sure
they
are
soldered
as
described
on
Page
11
of
this
Manual.
Be
sure
there
are
no
solder
“bridges”
between
circuit
board
foils.
3.
Check
to
be
sure
all
transistors
and
diodes
are
in
their
proper
locations. Make
sure
each
lead
is
connected
to
the
proper
point.
Make
sure
that
each
diode
band
is
positioned
above
the
band
printed
on
the
circuit
board
or
as
di-
rected
in
its
step.
4.
Check
electrolytic
capacitors
to
be
sure
their
positive
(+)
or
negative
(—)
mark
is
at
the
correct
location.
5.
Check
to
be
sure
that
each
IC
is
properly
in-
stalled,
and
that
the
pins
are
not
bent
out
or
under the
IC.
Also, be
sure
the
IC
stalled
in
their
correct
locations.
are
in-
6.
Check
the
values
of
the
parts.
Be
sure
in
each
step
that
you
wired
the
correct
part
into
the
circuit,
as
shown
in
the
Pictorial.
It
would
be
sy,
for
example,
to
install
a
22
kQ
(red-red
org)
resistor
where
a
2200
0
(red-red-red)
re-
sistor
should
have
been
installed.
Check
for
bits
of
solder,
wire
ends,
or
other
foreign
matter
which
may
be
lodged
in
the
wiring,
8.
Be
sure
all the
component
leads
are
cut
close
to
the
foil
on
each
circuit
board,
so
the
leads
do
not
short
to
the
chassis
after
the
circuit
boards
are
installed