Fluke 93 Service Manual page 101

CALIBRATION
ADJUSTMENT PROCEDURE
5-5
WARNINGt
To prevent personal
injury,
do
not
perform any diaaseembly procedures before
reading chapter
6.
When
the
ScopeMeter
Is
disassembled,
it
is
not possible to
apply
the
+12V programming
voltage
in
the
normal way.
It
Is
possible to
apply the
-!'12V
programming vol^ge by means
of
two
test clips
(see
tlgure 5.2).
Remove
all
voltage
sources from
the
ScopnMeter
Turn the
digital
Al
PCB. mounted
in
the
top
cover
so
that the display
and
the keyboard are
facing
down. Connect
the
•••12V
programming
voltage
to
the
appropriate places
on
the
PCB.
It
can be
helpful to
first
install
two metal screws
again.
See
figure 5.2.
Be
sure
not
to
short
circuit
with
the metal shielding,
mounted
on
the
analog A1
PCB.
Turn
the top
cover
and
the
mounted PCB. Connect
the
ScopeMeter
to
the
power supply and
switch the Instrument
on.
Go
to
the
SERVICE menu
and
press the
CALIBRATE
ScopeMeter
sotb<ey.
You can make
the
adjustments necessary
with
six trim capacitors
(three for
the attenuator of
each
channel) and
two
adjustment potentiometers (for^e Analog
ASIC).
*12V
Figure 5.2 Connecting
the
12V programming
voltage
for
Hardware
SCOPE
Calibration
Adjustments.
NOTE:
You
only
have
to
do Hardware
SCOPE
Calibration Ar^ustments,
if
you have
repaired the
ScopeMeter
in the
Attenuator sections or
In
the
Analog
ASIC
circuitry.
After
you have done
a
Hardware
SCOPE
Calibration Ac^'ustment or
you have
ar^usted
one
of
the potentiometers,
you
always
need
to
do a
full
(software)
SCOPE
and
METER
calibration,
ft
you
decide not
to
do
the
Hardware
Ca//Praf/or?
Adjustment now, you can advance
to
calibra^on
S5
by pressing
the
upper
seiect/adjust
key 4
times.