Troubleshooting Tree; Dc Ma Test; 77/23 Only); Dc Amps Test (73. 75/21, And 77/23 Only) - Fluke II Series Service Manual

Maintenance
PERFORMANCE
TESTS
DC
mA
Test
(75/21
&
77/23 Only) 3-12.
1.
Set the
output of
the
DC
Current
Calibrator
to zero,
and
connect
it
to
the
300mA
and
COM
input terminals of the
UUT.
2.
Set the
DC
Current
Calibrator to the output
shown
in
Table
3-5,
and
verify that the
UUT
display reading
is
within the
limits
shown.
Table
3-5.
DC
mA
Test
STEP
INPUT DISPLAY READING
CURRENT
75/21
&
77/23
1
+27
mA
26.57
to
27.43
DC
2
+200
mA
196.8
to
203.2
DC
DC Amps
Test
(73,
75/21,
and
77/23 Only)
3-13.
1.
Set the
DC
Current
Calibrator to
standby and connect
it
to the
10A
and
COM
input
terminals
of
the
UUT.
2.
Apply
currents as indicated in
Table
3-6,
and
verily that the display reading
is
within the limits
shown.
Table
3-6.
DC Amps
Test
STEP
INPUT
CURRENT
(5100B)
DISPLAY READING
1
+1.99999A dc
1.95
to
2.05
DC
CALIBRATION 3-14.
1.
Set the
DC
Voltage
Calibrator to zero, and
set
the
UUT
to the
VDC
function.
2.
Remove
the case
top cover
as
previously described.
3.
Connect
the
DC
Voltage Calibrator
to
the vn-*+- and
COM
input terminals of
the
UUT.
4.
Set
the
DC
Voltage
Calibrator for
an output of +3.000V
dc,
and
adjust
R8
for
a
display
reading of
+3.000V
dc
±
,001V.
TROUBLESHOOTING
3-15.
A
troubleshooting
tree
for the Series
n
meters
is
given
in
Figure 3-3. Faults are
listed
in
the order of
probability.
This
tree
gives a systematic approach
to isolation
of problems
to
a
component
or
component
area.
Complete
the
procedures
in the
order
listed
in this
table;
all
measurements
are
made
with
respect to
common.
Also,
supplemental toubleshooting procedures
are
presented in the following para-
graphs.
When
troubleshooting the 70 Series
II
meters,
use the precautions
listed
on
the
static
awareness sheet
to
prevent
damage
from
static
discharge.
3-9