Wavetek 132 Instruction Manual page 21

Table
4-2.
TROUBLESHOOTING CHART
(Continued)
Symptom
Probable Cause
Corrective Procedures
All
waveforms
low
in
amplitude
Power
Amplifier
a.
Check
front panel amplitude
control.
b.
Perform
balance adjustment
for
power am-
plifier.
Power
Supply
Check
for
correct
voltages.
All
waveforms
low
in
amplitude Power
Amplifier
a.
Check
front panel
amplitude
control.
b.
Perform
balance adjustment
for
power am-
plifier.
Power Supply
Check
for
correct
voltages.
Frequency out
of tolerance
Power
Supply Check
for correct
power
supply voltage
as stated
above.
Maladjustment Perform
calibration
procedure.
Sine
wave
not
in
spec Maladjustment Perform
sine distortion,
amplitude,
and
balance
adjustments.
Sine Converter Check
for
260
mV
p-p sine
wave
at
pin
4
of
IC8.
a. If
normal, check
sine
amplifier IC8.
b.
If
normal, check
A1
circuit.
Time symmetry
of
waveforms
not
correct
Maladjustment Perform time
symmetry
and frequency
adjust-
ments.
2.
Check
at coaxial-wire
lug
of function
selector
switch
for a 2.5
V
p-p square
wave.
If
normal,
check output
amplifier
(Q34
—
Q40).
3.
Unsolder and
lift
the
end
of
R51
(TP7). This
is
the output
of the integrator
and
input
to the
hysteresis switch.
The
generator loop has
now
been opened.
4.
Inject a 2.5
V
p-p triangle
waveform
into the
hysteresis
switch input
lead
(TP7).
5.
Check
at
the coaxial-wire
lug
of the function
selector
switch
for a 2.5
V
p-p
square
wave
at
the
injected
frequency.
a.
If
present, hysteresis
and output
switches
are functioning normally. Proceed
to
Step
6.
b.
If
abnormal, check
Q6
—
Q16
stages.
6.
Vary
frequency
dial
from ccw
to
cw
while
observing
TP11
with
a
scope.
Voltage
at this
point should remain
at
0
volts
throughout
dial
rotation.
If
a
voltage variation
is
observed,
check
IC1
stage.
7.
Vary
frequency
dial
from ccw
to
cw
while ob-
serving TP4. Voltage reading should vary from
0
to
approximately
—6
volts.
If
voltage
does
not
vary, check IC2
stage
and
IC1
stage.
8.
Vary
frequency
dial
from ccw
to
cw
while ob-
serving
TP9. Voltage
reading should remain
at
0
volts.
If
voltage
varies,
check IC3
stage.
9.
Vary
frequency
dial
from ccw
to
cw
while
observing
TP
10.
Voltage should vary from 0
V
to
approximately +6
V.
If
voltage
does
not
vary,
check IC2
stage
and IC3
stage.
10.
Vary
frequency
dial
from ccw
to
cw
while
observing TP8. Voltage
reading should remain
at
0
volts.
If
voltage
varies,
check IC4 and IC5
stages.
11.
Reinstall
R51.
DIGITAL
BOARD
If
a fault
in
the
logic circuit
of the
digital
filter
is
sus-
18