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6.4
GENERAL
INSTRUCTIONS
When
encountering a problem,
it
is
advisable
to
return
as
many
of
the
front
panel
controls
as
possible
to their
initial
settings
and
still
retain
the problem.
The
trouble-
shooting tables
in
this
section generally begin
at
these
initial
settings
and
specify
all
subsequent
setups.
Preset the
front
panel
controls
as
follows.
which
best describes the malfunction
and proceed
to
the referenced troubleshooting
table.
Follow through
the
checks
in
the troubleshooting
table,
using
schematics
and
assemblies as a
guide.
When
positive
results
are not obtained,
perform
the
in-
dicated corrective procedure.
Table
6-1.
Fault Isolation
Control
Position
Frequency
Dial
4.0
POWER
ON
FREQMULT(Hz)
..
1K
FUNCTION
Is
DCOFFSET
OFF
AMPLITUDE
MAX
CAUTION
To
prevent
damage
to
components,
turn
unit
off
while
removing
or replacing
components, connectors
or
pc
boards.
The
Suspected
malfunctioning condition should
be
double
checked
to
eliminate the
possibility of
improper
settings or
connections. Before attempting
fault isola-
tion,
the
unit
should
be checked
for
proper
line
voltage selection
(refer
to
Section
2).
A
good
visual
in-
spection
of
the
boards
and
chassis wires
for
damage
or
overheating
often
saves
much
time.
Once
the
malfunction
is
defined,
begin the
isolation
procedure by
selecting
an
indication
in
table
6-1
Indication
Table
1.
Fuse
blown,
no power
indication or
no
outputs.
6-2
2.
Function
outputs
missing
or clipped
when
TTL
sync OK.
Triangle
problem.
6-3
3.
Sine
waveform
problem.
6-4
4.
Square waveform
problem.
6-5
5.
TTL
sync
output problem.
6-6
6.
Generator frequency
does
not
respond
correctly
to
dial
and
VCG
input
6-7
7.
Waveform symmetry
problem.
6-8
8.
Problem on bottom
three
ranges
only.
6-9
9.
Generator
trigger
and
gate
mode
prob-
lem.
6-10
Table
6-2.
Power
Supplies
and
Generator
Loop
Indication:
Fuse
blown,
no power
indication
or
no
outputs.
Check
If
Faulty,
Check
1
Set
all
controls
in
their
initial
positions
(refer to
paragraph
6.4).
2.
Ensure
line
voltage
matches
instrument configuration
(refer to
Section
2).
Check
fuse.
3.
Check
C1
(
+
)
and
C2
(-)
for
±20
to
26V
unregulated
dc.
4.
Check
indicator
lamp.
5.
Check
C4(
+
)
for
+15
Vdc.
6.
Check
C5(-)
for
-15
Vdc.
Replace
fuse;
check
for
nor-
mal
operation.
a.
CR1
-
CR4.
b.
C1.C2.
c.
SW1.
d.
T1
,
RV1
,
F1 (bracket
as-
sembly).
DS1
and VR2,
wiring
E34
and
E33.
a.
VR1.
b.
Excessive
loading;
use
board jumpers
to isolate
cause.
a.
Q2.
b.
U2.Q1.
c.
Excessive
loading;
use
board jumpers
to isolate
cause.
6-2
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