Cleaning; Performance Tests; Initial Procedures; Display Test - Fluke 8050A Instruction Manual

4·26. Cleaning
CAUTION
Do not use aromatic hydrocarbons or
chlorinated solvents for cleaning. These
solutions wUl react with the plastic materials
used In the Instrument.
CAUTION
Do not allow the LCD to come In contact with
moisture. Remove the LCD from the Display
PCB A..embly before cleaning the
pcb,
and
do not In8tall the LCD until the pcb Is
completely dry.
4-27. Clean the front panel and case with a mild solution
of detergent and water. Apply the solution with a soft
cloth. Do not apply the solution directly to the front
panel. Clean dust and debris from the pcb's with low-
pressure (20 psi) dry air. Oean contaminates from the
pcb's with isopropyl alcohol and a soft brush. Rinse with
demineralized water while scrubbing with a soft brush. To
dry the pcb's, remove any ICs in sockets and use low-
pressure dry air, then bake at 50 to 60°C (124 to 140°F)
for 24 hours. Replace any components removed for
cleaning and reassemble the instrument.
4·28. PERFORMANCE TESTS
4-29. The performance tests are used to compare the
8050A performance with the list of specifications given in
Section 1. We recommended that you run the
performance tests for incoming inspection and periodic
calibration. If the instrument fails any ofthe performance
tests, then calibration adjustment andj or repair is
needed.
4·30. Initial Procedures
4-31. Before begining each of the tests, perform the
following:
1. Remove all test leads.
2. Check the fuses and, if necessary, replace.
3. Set the POWER switch to ON, and allow the
8050A to stabilize for approximately 5 minutes.
Conduct the tests in an environment with an
ambient temperature of 23
±
5°C (73
±
9°F)
and a relative humidity of less than 80%.
4-32. Display Test
4-33. Use the following procedure to verify the proper
operation of the LCD:
1. Select the kO function, 2000 range.
MAINTENANCE
PERFORMANCE TESTS
2. Verify that the overrange indicator (1) is
displayed.
3. Connect the red test lead to the VjkOjS input
connector and the black test lead to the
COMMON input connector.
4. Refer to Table 4-3. Short thetestleads together
and verify that the display reads as shown for
each of the resistance ranges.
Table 4-3. Display Test
SELECT RANGE DISPLAY
200SL
00.00*
2kSL
.0000*
20 kSL 0.000
200 kS1 00.00
2000 kSL 000.0
20MSL 0.000
*Due to test lead .resistance, the least significant
digit(s) may fluctuate by several counts.
5. Select the DC V function, press the REF %:
switch to the in position (on) and verify that
four decimal points appear on the display.
6. Select the 200V dc range.
7. Connect the DMM Calibrator to the 8050A as
follows: HI to the V
I
kOj S input connector and
LO to the COMMON input connector.
8. Adjust the DMM Calibrator until the 8050A
displays
+
188.88V dc exactly.
9. Verify that all segments of the 8050A LCD are
illuminated and the HV annunciator appears in
the display.
10. Set the DMM Calibrator for a -39V dcoutput.
11. Verify that the HV annunciator disappears and
the polarity indicator changes to (negative).
12. Select the dB function on the 8050A, then set
the RELATIVE switch to ON (in).
13.
Verify that the dB and REL annunciators are
illuminated.
14. This concludes the Display Test. Remove
power from the DMM Calibrator before
dismantling the test setup.
4-5