Fluke 8020A - 4-33. DC Current Test; 4-35. CALIBRATION; 4-38. TROUBLESHOOTING

4 - 33. DC Current Test
a.
Remove the top cover from the
8020A using the
access procedure given earlier in this section.
4-34.
The following procedure is used to check the
operation and accuracy of the DC current ranges.
b.
Set the
8020A power switch to ON and select
the 200
mV DC range.
I
l
a. Set the output of the dc current source to zero
e.
Set the output of the dc calibrator to
+190.0
mA. mV and connect it to the 8020A input
terminals;
+ to V/KR, and - to COMMON.
b. Connect the output of the current source to the
mA and COMMON input terminals on the
d.
8020A.
Adjust the DC CAL pot (R6), as shown in
Figure 4
- 1, for a display of 190.0 or 190.1. (Use a
plastic adjustment tool or a common plastic
c.
With reference to Table 4 - 5 select the 8020A
screw driver for all adjustments)
current range indicated in step 1, and set the
-
calibrator output to provide the corresponding
e. Disconnect the dc calibrator from the
8020A
8020A input current. Verify that the display
input terminals.
reading is within the limits shown.
f. Select the 200
mV AC range on the 8020A.
Table 4 - 5. DC Current (mA) Checks
d.
Execute and verify steps 2 through 4 of Table 4
- 5
using the procedure described in step c.
4 - 35. CALIBRATION
STEP
1
2
3
4
4
- 36.
Under normal operating conditions the
8020A
should be calibrated once a year to maintain the
specifications given in Section
1 of this manual. If
instrument repairs have been made or if the unit fails the
performance test, immediate calibration is indicated.
Equipment required for calibration is given in Table 4
- 1.
If the necessary equipment is not available, your nearest
authorized Fluke Technical Service Center will be
happy to help. A list of these service centers, as well as
shipping information, is given at the back of this
manual.
INPUT
CURRENT, DC
$1.9 rnA
- 19 rnA
$190 rnA
+1900rnA
CURRENT
RANGE
2 rnA
20 rnA
200 rnA
2000rnA
4 - 37.
Use the following procedure to calibrate the
8020A:
DISPLAY
READING
1.885 to 1.915
- 18.85 to 19.15
188.5 to 191.5
1885to1915
NOTE
This procedure assumes an ambient temper
-
ature of 23f 2" C (70 to 77'F) and a relative
humidity of less than
80%. The temperature
of the unit should be allowed to stabilize for at
least
30 minutes before calibration begins.
g.
Set the output of the ac calibrator to 190 mV at
100 Hz, and connect it to the
8020A input
terminals;
V/KR and COMMON.
h.
Adjust the AC CAL pot (R4) for a display of
190.0 (an occasional flash of
f 1 digit is
acceptable).
1. Select the 2VAC range on the 8020A and set the
ac calibrator output to
1.9V at 5 kHz.
1.
Adjust the HF ADJ (Cl) for a display of 1.895
to 1.905.
k.
Execute the performance test given earlier to
ensure that all fixed range resistors and other
nonadjustable components are operating within
thier specified limits.
4 - 38. TROUBLESHOOTING
Static discharge can damage MOS com -
ponents contained In the 8020A.
4 - 39.
When troubleshooting or repairing the
8020A
use the following precautions to prevent damage from
static discharge:
a. Never remove, install or otherwise connect or
disconnect components without first turning
the
8020A power switch to OFF.
b.
Perform all repairs at a static
- free work station.
c.
Do not handle IC's or pcb by their connectors.
4
- 5