In Case Of Difficulty - Heathkit V-4 User Manual

READING IDE METER
SCALE
The
voltage
markings
t>n
the
range switch refer
to
the
FULL
SCALE
reading.
The
scale
is
marked
0-10 and 0-30
for voltage.
Oh
the 3 Volt range, read
the
0-30
scale
and drop
the zero.
On
the
10 volt range, read
the
0-10
scale direct.
On
the 3D
Volt
range, read
the 0-3O scale
direct.
On
the 100 Volt range,
read
the
0-10
scale and add one
zero.
On
the
300 Volt range,
read
the
0-30
scale
and add one
zero,
On
the
1,000 Voll range, read
the
0-10
scale and
add two zeros.
The
resistance
marking or ohms
scale refers
to
the lowest
resistance
range
(Rxl).
For
the other
ranges,
add
the
proper number
of
zeros
(add
two zeros
lor
RxlOO, add four zeroslor
RxlOM, add
six
zeros
for
Rxl
Meg).
On
the
Rxl Meg
range,
the
scale can also be considered
to
read
directly
in
megohms.
ACCURACY
The
accuracy
of
most meters
is
rated
al
2%
of lull scale on
DC
and 5%
of
full
scale on
AC
The
Heathkit
VTVM
easily
full ills
these requirements.
When
comparing
with other instruments, con-
sideration
should be given
to
the
possibility that the other Instruments
variation
might be
the
opposite
of
the
HeatJikLt
making
a
possible variation
of
4&
on
DC
and 10% on
AC
IN
CASE OF DIFFICULTY
1.
Recheck
the wiring-
Most cases
of trouble
result
from wrong
or reversed
connections. Often
having a
friend cheek
the
wiring
will
reveal
a
mistake
consistently overlooked,
2.
Check
the tubes,
3. If
the
pointer swings
lull
scale
to the right
and
slays there with switch
set to
DC
+,
check
for
an open
Circuit
or
high
resistance connection
someplace between
the grid pin +4
of
the
and ground, This might
be
due
to
a wrong
connection
to
the selector switches,
poor connection
or possibly
nr.
open
resistor.
II
the
instrument does
not
operate on any
function,
a check
of
the
power
supply,
6KNT
and
its
associated
meter
circuit
is
suggested.
If
the
instrument
only
fails to
function on
AC
measurements,
then
a
check
of
the
6HS
and
Its
associated
circuits
is
indicated-
if
the instrument
only
fails to
function on ohms,
the difficulty will probably
lie
in the batteries
or
the
ohms
multipliers.
Proper
operation on
DC
should
first
be secured
before an
attempt
is
made
to
use
the
instrument
on
AC
Or ohms,
4.
Check
the
operating voltages.
The
following
voltages are
measured
to
Chassis: Pin
fi2
or #5
on
65N7
tube
or
+ lug
on
rectifier
40-70
Volts
positive. Single terminal
striu
60-100
Volts
negative. Pin *7
On
6HG
or
65N7
or
"hot" lug
on
pilot
light
socket 5-6 Volts
AC,
5.
Check
continuity
through
DC
test Cable.
Make
certain
that
the shielding
is not shorted
to
center
conductor,
6.
Write
to
the
Heath
Company
describing
your
difficulties and
giving
all
possible
details,
such
as voltages obtained, meteT
indications
if
any,
model number
etc.
We
will
attempt
to
analyze
your
trouble and
advise
you
accordingly.
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