Fluke 93 Service Manual page 154

7-28
CORRECTIVE MAINTENANCE
7.1.7
Analog A2
PCB
Troubleshooting.
7.
1.7.1
Test point
signals.
The
analog
A2
PCB
is
provided
with test points,
marked:
TP" See
figure 10.4:
A2
PCB
layout (wired
components
side).
These
can be used
to
check
correct functioning
of
the
PCB.
AH measurements
are
made
in
the
default
MASTER RESET
condition
(start
the
measurements
in
the
ScopeMeter
using
MASTER
RESET).
A MASTER RESET
is
performed as
follows:
1
,
Rem
0ve
al
I
signals
f
rom
th
e
Scope
Meter,
2.
Power
the
ScopeMeter
with the
Power
Adapts
r/Battery
charger
PM
8907.
3.
Turn
off
the
ScopeMeter
4, Hold
down
the
LCD
key
arvi
press the
ON/OFP
key simultaneously.
Two
beeps
are
audible,
and
all
volatile
memories
{RAM
with battery
backup) are
reset.
The ScopeMeter
is
automatically set
to
the
meter
mode.
NOTE:
For
the
measurements on
Test Points W1...529
and
901...
921 apptya
W
kHz
square
wave
sigr\al to
the
channel
A
BNC. Press
the
SCOPE
button
to
go
to
SCOPE
mode
and
press
AUTOSET
to
get a
stable picture
on
the LCD.
NOTE:
For
the
measurements on
Test Points
700...
906
first
switch on
the
ScopeMeter
using a
MASTER RESET
Then
press
the
SPEC/AL FUNCT/on
key
and
the
GENERATE
softkey.
Use
the
select/adjust
keys
to
select ^square 1.95
kHz'',
and
press
the
right
most
ENTER
softkey
to
aciiyete
the generator.
Use another
osti
I
loscope with high input
impedance and
10:1
probe
to
measure
the signals
on
the
lest
points.
See
table 7.7:
Table 7.7
Oyen/iew
signals
on
Test Points (TP)
on analog
A2
PCB.
Logic 0=0V, Logic
1=+5V
TP Name
Scope
Freq.
Data
Description
101 0
102
0
103
[
^
0
1
«6
104 0
r
•••0
106
0
I
133
107
ATTB-A [
0
108
0
i
-1B*w
109
POS-CHB
I
0
0
Base V2112
Output
D2101
Output
N2101
Collector
V21 05
Base V2104
Coliector
V2111
TP
for
OFFSET DAC
POS-CHB
201
0 Base V2212