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Table
4-2.
TROUBLE-SHOOTING GUIDE
(continued)
Symptom
No
Output
Signal
but
SYNC
output normal
No
SYNC
Output
but
Output
normal
No
SINE
Output
TRIANGLE
and
SQUARE
are
OK
Badly
Distorted
SINE
Output
.
.
TRIANGLE
is
OK
No
SYNC
and
50n OUTput
.
.
.
SQUARE WAVE
Output
has
Abnormally Slow
Rise or
Fall
Times
TRIANGLE
Output
has Constant.
.
.
.
Positive
Slope with change
of
Frequency
TR
I
ANGE
Output
has
Constant
^
.
.
.
Negative slope
with
Change
of
Frequency
Checks
VCG
Amplifiers
IC3-IC6
Continue
Signal
Output
at
TRIG
& GATED
MODE
Corrective
Action
connected between
the
anode
of
CR5
and
Sweep
Board.
If
output
is
back
to normal, trouble
is
on
the
Sweep
Board.
Check
for defective
Q35,
Q39
and
other
circuitry
on
tiie
Sweep
Board. Otherwise, trouble
is
on
the
Main
Board.
The
output
amplifier
is
malfunctioning;
see
Output
Amplifier
Check
outlined below.
The
Sync
Amplifier
is
malfunctioning;
Check
Q19
and
Q20
for
proper
operation.
Sine Amplifier
is
malfunctioning;
See
Sine Amplifier
Check
outlined
below.
Sine
Module
is
malfunctioning
and
should be
replaced.
First
Check
Q34
or
Q35
for possible trouble.
The
Triangle
Generator
is
not
functioning properly.
Check
Triangle Amplifier, Hysteresis Switch,
Diode
Gate, and
VCG
circuits.
Check
all
bypass
capacitors
(C103,
C104, C93,
C94
and C97)
in
the
Output
Amplifier.
Check Output
Amplifier
as
outlined
below.
Check
Q23
and
Q25
for possible trouble;
then
check
IC4and
IC6 and
their
associated
circuitry.
Check
Q22
and
Q24
for possible trouble;
then
check ICS and
IC5 and
their
associated
circuitry.
With
SYMMETRY
control
set
to
NORM,
slowly turn
FREQ
DIAL
from
0.1
to
10 and
observe the
following:
a)
Voltage
at
emitter of
Q21
should
move
from 0
to
—5
volts.
b)
Source
of
Q22
remains
at
0 and
drain
moves from +15
V
to
+10
V.
c)
Source
of
Q23
moves from
0
to
—5
V
and
drain
moves
from
-15
V
to
-10
V.
d)
Source
of
Q24
moves
from
+15
V
to
+10
V.
e)
Source
of
Q25
moves from
—15 V
to
—10
V,
f)
Voltage
at
drain
of
Q27
follows voltage
at
gate of
Q26.
g)
Voltage
at
drain of
Q29
follows voltage
at
gate of
Q28.
a)
Check
the proper operation of IC4,
IC5,
Q32
and
the
associated circuitry
on
the
Sweep
Board.
b)
Check
for the correct
logic
level
according
to the
proper
table
below.
4-6
12/70
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