Fluke 8506A Instruction Manual page 119

8506A
1.
First
ensure
that the rear
panel Calibration
Switch
is
off,
then
push
the
POWER
button to
OFF
and remove
the line
power
cord.
2.
Remove
the top cover, then
remove and
disassemble
the
Controller module.
3.
Install
(or replace) the Calibration
Memory
chip
(U20 on
the Controller
PCB).
4.
Reassembly and
install
the Controller
module,
then replace the top
cover.
5.
Verify
again that the Calibration Switch
is
off,
then reconnect the
line
power
cord
and push
the
POWER
button
to
ON.
6.
Refer
to
Appendix 7B
for
Calibration
Memory
programming
instructions.
4-21. Front Panel
PCB
Removal
4-22.
Use
the following procedure
to
remove
the
Front
Panel
PCB:
1.
Note
the position
of
any
LEDs
needing
replacement.
Push
the
POWER
control to
OFF
and remove
the line cord.
2,
Remove
the multimeter top cover
(six
screws).
3.
Remove
the front panel
bezel.
Press
down
on
the bezel center top
and
pull out.
4.
Remove
the
five
screws securing the
Front
Panel
PCB. Unplug
this
pcb by
alternately pulling
up
gently
on
its
upper
corners.
Once
disconnected,
work
the
pcb forward
to clear the
power push
button, then
retract
it
through
the front opening.
5.
If
necessary, replace
any
defective
LEDs.
6.
Replace
the
Front Panel
PCB
and
the bezel
in
the reverse order.
4-23.
Power
Supply
PCB
Assembly Removal
4-24.
Remove
the
Power Supply
PCB
Assembly
using
the following procedure:
1.
Push
the
POWER
button
to
OFF
and remove
the
line
power
cord
from
the
multimeter.
2.
Remove
the three buttonhead screws attaching
the
Power Supply
to the rear panel.
As
seen
from
the rear,
one of
these
screws
is
found along
the
Power
Supply
left
edge; the other
two
secure
both
the
feet
and
the
Power
Supply
right
edge.
3.
Pulling
from
the
rear, retract the
Power Supply
PCB
with
a
gentle
rocking motion. Once
disconnected
from
the
card edge connector
at the
front, the
pcb
slides
straight back.
4.
Replace
the
Power
Supply
PCB
by
reversing
the
steps
above.
The
left
center
buttonhead screw
also serves as a
ground connection between
the
Power
Supply and
the multimeter
chassis.
Tighten
this
screw
securely.
4-25.
Power
Supply Interconnect
Assembly
Removal
4-26.
Remove
the
Power
Supply
Interconnect
Assembly
using
the
following procedure:
1.
Remove
the
Front Panel and Power
Supply.
2.
Remove
the three
screws securing
the
Power
Supply
Interconnect
Assembly
to the
framework.
3.
Disconnect the card edge connector of the
pcb
from
the
Motherboard
connector.
Lift the
pcb
out
through
the front
framework.
4.
Reassemble
in
the reverse order.
4-27. Front/Rear Switch
Assembly
4-28.
REMOVAL
4-29.
Use
the
following procedure
to
remove
the
Front/ Rear Switch Assembly:
1
.
Push
the
POWER
control
to
OFF
and
remove
the
line
cord
from
the
multimeter.
2.
Remove
the
multimeter top
cover.
NOTE
As
seen
from
the front, the Front
/
Rear
Switch
Assembly
is
housed
in
the
right side
chassis.
Although
the
Front
j
Rear Switch
Assembly
is
mechanically secured
to the
vertically aligned rear panel,
it
is
electrically
connected
to
the horizontally aligned
Motherboard PCB. Removal and
replacement of
the
Front
j
Rear
Switch
Assembly
each
require
unique procedures.
3.
At
the front panel right
side, pull
on
the three
selector buttons
until
they disconnect from
the
Front/
Rear Switch Assembly.
4.
Remove
the three
buttonhead
screws securing
the
Front/'
Rear Switch Assembly
to the rear panel.
Identify
two
of these screws
as
also attaching
two
of
the rear
panel
feet.
5.
Next, remove
the three
screws securing
the
assembly
front-to-back
along
the
right side.
4-5