Heathkit IM-16 - Troubleshooting Chart

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-
@
(
)
Connect
the
common
test
lead
to the
ground
side
of
the AC
powerline,
andthetest
probe
tip to the
hot
side
of
the
power
line.
(
)
Carefully adjust
the
AC
Calcontroluntilthe
meter indicates the line voltage.
(
)
Disconnect
the test
probe
and
common
lead
from
the
power
source.
If
you
have an accurate
AC
voltmeter,
you
can
check the
AC
calibration
of
youl
Voltmeter
by
first
checking
the
source voltage with
one
volt-
meter and then
with
the
other.
Adjust your
IM-16
Voltmeter AC
Cal
control
foranidentical
reading.
Always
calibrate
on
the
50
volt,
or
higher,
scale.
OHMS
ADJUSTMENT
After
the Bias
Adjust
and ZERO ADJUST
con-
trols
have
been
properly
set
for DC
voltage
measurements, the
OHMS
ADJUST
control
will
calibrate
the
ohmmeter circuit for resistance
measurements. In the
following steps
you
will
adjust and
check the
ohmmeter operation.
(
)
Set
the
FUNCTION
switch to Ohms, and the
OHMS
range switch full
clockwise to
RX-
1
MEG.
(
)
Turn the
OHMS
ADJUST
control clockwise
turtil
the
meter
pointer
rests
over
the
last
mark at
the right-hand end
of
the
green
Ohms
scale.
(
)
With the
test
probe
switch in the
AC-OHMS
position,
touch the
probe
tip to the
common
test
lead.
The
meter should
return
to zero.
()
Turn
the
test
probe
switch to the
DC
posi-
tion
and again touch the
probe
tip to the com'
mon lead.
The
meter should now indicate
approximately
1
on
the
Ohms
scale.
This
is the
1
megohm resistance in
the
probe,
and its tolerance
may result in
a
reading
slightly
different
from 1
megohm.
Change
the
OHMS range
switch
to RX100K.
The
meter
should
now
indicate
approxi-
mately
10
whentheprobe
tip is touchedto
the
common
lead.
()
(
)
Turn
the
OHMS
range
switchtoRXl,
andthe
probe
switch to
the
AC-OHMS position.
Touch
the
probe
tip to the
common
leadand
the
meter
should indicate
almost
zero.
Note
that
the
resistance
of
thetest
leads may
be as much
as
.2
ohms, which
is indicated
on
the
meter.
This
is a normal
condition,
and
this
test
lead resistance
should
be con-
sidered
in
critical
lowresistance measure-
ments.
Your
Voltmeter
is now
completely
calibrated.
Proceed
to the
Final
Assembly
instructions
that
follow.
FINAL
ASSEMBLY
Refer
to
Pictorial
L4
for the
following
steps.
(
)
Place
one
of
the
cabinet shells
over
ttre
Voltmeter
chassis
with the
sloping edge
of
the
shell
toward the
front. Secure the
cabi-
net shell to the
side
rails with two
6-32
x
1/4"
philips
head
screws
at
each end as
shown in
Pictorial
14.
(
)
Turn
the Voltmeter
over
and
install
the
other
cabinet
shell.
Use
two
6-32 x
l/4,'
phillips
head
screws
at
each end"
(
)
Refer
to
Detail
14A and
installaptasticfoot
near
each
corner on
the
bottom cabinet
shell. Remove
tlte
paperbacking;
thenpress
the
foot
onto
the
cabinet shell in
the
position
shown. A plastic
foot
can
be moved,
if
necessary,
up to
one-half hour aJter
the
backing
is
removed. After
this,
the adhesive
permanently
bonds the
foot to the
cabinet
shell.
This
completes
the
assembly
of
your
kit. The
following
pages
present
information
on
Operation
to help
you
make
the
best
use
of
your
Voltmeter.