Initial Tests; Resistance Check; Voltage Check - Heathkit SW-717 Assembly

INITIAL TESTS
lf
you
have
a VOM (volt-ohm-milliammeter)
or a
VTVM
(vacuum
tube voltmeter) , refer
to
Figure
1 (fold-out
from
Page
40) and perform the
resistance and voltage
tests
which
follow.
These are
to
insure that there
are
no short circuits
in
the power supply, and
that the
correct voltage
is
present.
lf
you do not
observe
the
proper meter
readings
when you
make
the
checks,
turn to the
"ln
Case
of
Diff
iculty"
section.
lf
you do not
have
the
meters, proceed
directly
to
the
"Alignment"
section.
RESISTANCE CHECK
( )
Set
your
ohmmeter
on its R
x
10
scale.
Clip
the
common
(negative)
lead
of
the
ohmmeter
to
the
chassis
and
the positive
lead
to
lug
1
of terminal strip
BF. The
resistance
reading
should
be
not
less
than
150
O.
lf
you do not
obtain this minimum
reading, DO
NOT connect
the
Receiver
to
the
electric
outlet until
the
difficulty
is
corrected,
( )
Disconnect the ohmmeter.
VOLTAGE
CHECK
( )
With the
Receiver
off,
temporarily
push
the
two
connectors on the black
and
white twisted
pair onto
the two
speaker lugs.
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Position the knob index marks according
to
Detail
25E.
Place
the
ANL
switch on the rear panel at OFF.
Set
your
voltmeter
to
the proper
range
to
read
15
volts.
Connect
the voltmeter common
lead
to
the
chassis.
Connect
the positive
lead
to
lug
1
of terminal
strip BF.
Insert
the
line
cord into the electric outlet
and
turn
the
Receiver
on by
rotating
the
VOLUME
knob
clockwise
until a click
is heard.
The
two dial
lamps
should
light
and
the voltmeter should
indicate
8
to
13
volts.
lf
you
see
any
evidence
of
short
circuits or
overheated
components
(such
as wisps
of
smoke),
turn
the
Receiver
off
immediately and
turn to the
"ln
Case
of Difficulty"
section.
Disconnect the
voltmeter.
Turn
the VOLUME
control
so
the index mark
is
at the
12 o'clock
position. Then touch the
exposed lead
of
C22,
the
10
frF electrolytic capacitor
mounted
vertically
on the circuit
board.
A
hum should
be
heard.
This indicates the audio
stages
are
working.
Turn
the
Receiver
off
and disconnect
the speaker leads
and
the line
cords.
HICATHI<IT'
43