Fluke 8020A - 4-15. LSI (U8) ACCESS; 4-17. Cleaning; 4-19. Battery;Fuse Replacement; 4-21. PERFORMANCE TEST

4 - 15. L S I (~8) ACCESS 4 - 1 9. Battery/Fuse Replacement
4 - 16. Use the follow~ng procedure to remove/replace WARNING
the AID Converter and Display Driver IC, U8.
BATTERYIFUSE REPLACEMENT SHOULD
a. Remove the pcb assembly using the
component/ pcb access procedure.
ONLY BE PERFORMED AFTER THE TEST
LEADS HAVE BEEN REMOVED FROM THE
INPUT JACKS, AND THE POWER SWITCH IS
b. On the bottom of the pcb locate and remove the
SET TO OFF.
two phillips head screws from the display
4
- 20.
Refer to Section 2 of thls manual for battery and
assembly.
fuse replacement procedure. Use only the recommended
c.
Lift the display assembly from the pcb to expose
replacement types.
U8 Is a MOS dTvice and is subject to damage
%
by statlc discharge. Observe the precautlons
glven later In thls section under
troubleshootlng before attemptlng to remove
or replace
U8.
d.
Use a screw driver or a reasonable substitute to
rock (by prying up on each end of the
IC) the 1C
out of its socket.
e.
When installing
U8 make sure all pins are lined
up in the socket, and then carefully press it into
place.
f.
When re - installing the LCD Bracket be sure to
line up the flex cable holes with theextensians on
the bracket before tightening the bracket screws.
4 - 17. Cleaning
4
- 21. PERFORMANCE TEST
4 - 22.
The performance test is used to compare the
K020A performance with the list of specifications given
In Section I of this manual. It is recommended for
incoming inspection, periodic maintenance, and to
verilj/ specifications. If the instrument fails any part of
the test, calibration
and/or repair is indicated.
4 - 23. Initial Procedure
4 - 24.
Each of the individual procedures that comprise
the perfo;mance test assume that the following
conditions exist.
a. The unit has been allowed to stabilize and will
be tested at an ambient temperature of 23
f
5O C(73f go F).
b. 'l'he fuse and battery have been checked and, if
necessary. replaced.
c.
The power switch has been set to ON.
CAUTION
4 - 25. Display Test
Do not use aromatlc hydrocarbons or
chlorinated solvents for cleaning. These
4 - 26. The following procedure is used to test the
solutlons wlll react wlth the plastlc materials
used In the Instrument.
operation of all display digits and segments.
'\
a.
Select the 20
hi1 range. -1 he d~splay should be
CAUTION
blanked with the exception of the overrange
D O not get the liquid crystal dlsplay wet.
indicator (I) in the left hand column and a
e
Remove the display Assembly before washing
decimal point in the center of the display.
the pcb and do not Install it until the pcb has
been fully drled.
4 - 18.
Clean the front panel and case with a mild
solution
of detergent and water. Clean dust from the
circuit board with low pressure (<20 psi) dry air.
Contaminates can be removed from the circuit board
with demineralized water and a soft brush (remove the
Display assembly before washing, and avoid getting
excessive amounts of water on the switches). Dry with
clean dry air at low pressure, and then bake at 50 to
60° C
for 24 hours.
b. Connect
a decade resistor between the C' K11
and COMMON input terminals.
c.
Set the decade resistor to 10 kll and verify a
display of 10.00
f 3 digits.
d.
Sequentially increase the resistance in
1. I I kn
steps and verify the operation of each digit and
~ts segments.
e. Disconnect the decade resistor at the input
terminals. and select the 2000
kn range. A
decimal point should not be displayed.