Circuit Discriptions; Introduction To; General - Fluke 93 Service Manual

CIRCLUT
DESCRIPTIONS
3
3
CIRCUIT
DESCRIPTIONS
3.1
INTRODUCTION TO
CIRCUIT DESCRIPTION
3.1.1
General
This chapter prasants
a
lay
a
rad description of the
ScopeMeter
circuitry. First
the
ScopaM
star's
overall
theory
of
operation
Is
described,
referring
to the
overall
block
diagram
(section
3.2).
Tho
next section gives
some
Information
conoeming
the
ScopeMeter's
data
acquisition.
Then
the
circuits
on both
digital
(A1)
and
analog (A2) pnntad
circuit
twards (FOB)
are described.
After
a
short introduction,
a
detailed
circuit
description
is
given
for
each
circuit
pan.
The
various circuit descriptions refer
to
the
circuit
diagrams
in
chapter
10.
NOTE:
The
large
digital
(A1)
and
analog
(A2) printed
circuit
board diagrams
are provided
as
separate drawings.
Whenever
a
signal line
continues
on
anofher drawing,
it
is
indicated
by
the following
comment:
"FROM
A
'
—
>
coming
from
the digital (A
1
)
drcuit (figure 10.2)
"TO
A2a
"
—
>
the signal continues
on
the
first
circuit
diagram
of the analog
A2 PCB
(figure 10.5)
3.1.2
Location
of electrical
parts
The
Item
numbers
of
C.,.,
R..„
V,..,
H.... D...
and
K...
have been
divided Into
groups. TTiese groups
relate to
the functional parts
on
the
PCBs:
Table
3. 1
Location of
electrical parts.
Item
number
Furtctional part
PCB
diagram
'
1200-1299
pP,
Oigitaf
ASIC
and
related circuitry
A1
1
A1
1300-1399
battery sense,
RAM
power,
backlight
A1
AT
I
1400-1499
1
LCD
aryj related
circuitry
A1
A1
1SOO-1599
ON/OFF
circuit
A1
A1
1600-1699 keypad
A1
A1
2100-2199
attenuator channel
B A2 A2a
2200-2299
attenuator channel
A
A2 A2a
2300-2399
Analog
ASiC and
ADC
A2
A2aZb
2500-2599
battery
charger and power
supply
A2 A2c
2700-2799 EXTemal
Input-Zoutpul
circuitry
A2
A2b
2800-2899
generator
A2 A2b
2900-2999
analog
control circuitry
A2 A2a