Display Removal; Cleaning; Special Test Devices - Fluke 8010A Instruction Manual

MAINTENANCE
GENERAL INFORMATION
4-17.
DISPLAY
REMOVAL
4-18.
Use
the following procedure
to
remove
the
LCD:
1.
Preform
the
Main
PCB
Access procedure.
2.
Turn
the instrument
right side
up.
3.
Remove
the
two
screws
that
connect
the
Main
PCB
Assembly and
the
Front Panel Assembly.
The
screws are located at the right front of
the
instrument.
4.
Carefully
slide the front
panel forward
until
it is
clear
of the
switches
and
the
LCD.
Let
the
Front Panel Assembly drop
clear
of
the
LCD.
5.
Remove
the
two
screws connecting
the
LCD
to
the
Main
PCB
Assembly.
6.
Place your
fingernail
under the grey tabs on
the
display
frame and
lift
them
free
of the
screwposts on
the display
mounting
bracket.
7.
Rotate
the display
frame forward and
down
until
the
two hooks on
the
bottom
of the
display
frame
release the
display mounting
bracket.
8.
The
LCD
may now
be
lifted free
from
the
display
mounting
bracket.
9
.
A
small length of
flat,
flexible material
may
fall
out.
This
is
the "zebra
strip"
an
elastomeric
strip
of
alternate areas
of conductive and
non-
conductive
material.
When
the screws are
tightened to
hold
down
the display assembly,
the zebra
strip
provides
electrical contact
between
the pins
on
the
LCD
and
the land
pattern
on
the
Main PCB. The
zebra
strip
is
located in
a channel
on
the display
mounting
bracket.
10.
To
reassemble, reverse the previous procedures
in
a
logical order.
4-19. Cleaning
CAUTION
Do
not use aromatic hydrocarbons
or
chlorinated solvents
for
cleaning.
These
solutions
will
react with the
plastic materials
used
in
the instrument.
CAUTION
Do
not get the
liquid crystal
display wet.
Remove
the display
assembly
before
washing
the
pcb and do
not
install
it
until the
pcb has
completely
dried.
4-20.
Clean
the front panel
and
case with a mild
solution
of detergent and
water.
Clean
dust
from
the
circuit
board
with
clean, dry,
low
pressure
air
(<20
psi).
Contaminates
can be removed from
the
pcb with
demineralized water
and
a
soft
brush (remove
the
LCD
before washing
the
Main
PCB
Assembly and
avoid
getting excessive
amounts of water on
the
switches).
Dry
with
clean, dry,
low
pressure
air,
and
then bake
at
50°
C
to
60°
C
(124°
F
to
140°F)
for
24
hours.
4-21. Special Test Devices
4-22.
There
are
two
devices
which you
can
make
that
will
improve
the efficiency
and accuracy of
the
Calibration Procedure.
The
two
devices are the
190
Test
Set
and
the
1.90 Test
Set.
They
insure
good
electrical
contact
and
consistent
results.
The
following
paragraphs
describes the construction of the Special Test Devices.
4-23.
1
90 TEST
SET
4-24.
The
components needed
are:
one
190 ±0.05%
precision
resistor
and one
single
banana
connector with
two
isolated terminals.
The Pomona,
Two
Terminal
Isolation
connector
(Model number
1390-2)
and
the
Dale
Electronics,
Inc.
190
Precision Resistor (RS-1/4)
are
recommended
for constructing the
190
Test
Set.
Refer
to
Figure
4-2 for assembly
instructions.
4-25.
1
.90
TEST SET
4-26.
The components needed
are:
one 1.90 ±0.05%
precision resistor
and one
single
banana
connector
with
two
isolated terminals.
The Pomona,
Two
Terminal
Isolation
connector
(Model number
1390-2)
and
the
Dale
Electronics,
Inc.
1.90 Precision (RS-1/4)
are
recommended
for constructing the 1.90
Test
Set.
Refer
to
Figure 4-2
for
assembly
instructions.
Figure
4-2.
190
and 1.90
Test Sets