Wavetek 182A Instruction Manual page 23

Table
6-7.
VCG
Circuit
Indication:
Generator does
not
respond
correctly to dial
and
VCG
input.
Check
If
Faulty,
Check
1
.
Set controls
to
initial
positions
(refer to
paragraph
6.4).
Check
for
normal
operation.
2.
Check
for
approximately
+
15V
at
E1
1
a.
E10, E11
and E12
wiring.
b.
+15V
supply.
c.
Dial potentiometer.
3.
Check
for
±10 mV
at
U1
pin 13.
U1.
4.
Check
U1
pin
14
for
approximately
-5V.
U1.
5.
Check
that
as the
dial
is
rotated
from
4.0 to .004,
the voltage
at
U1
pin
14 varies
from approximately
-5
to 0V.
U1.
6.
Ensure
that
U1
pin
5 remains
at
a constant
0V
±40
mV
as the
dial
is
varied.
U1, U4,
and U6
circuits.
7.
Check
that,
as the
dial
is
rotated from .004
to 4.0,
the voltage
at
U1
pin
1
does not saturate near
-
15V
or
+
15V
(typical
range
is
between
-
10V and
+
10V)
and
stops varing with the
dial.
Q6, U1,
and U6
circuits.
8.
Check
that
as the
dial
is
rotated
from .004
to 4.0,
U6
pin
8 varies from
approximately
-15V
to
-10V.
U6, U1,
and Q6
circuits.
9
Check
that,
as
the
dial is
rotated
from
.004 to 4.0, the voltage at
U1 pin 7
does not saturate near
+15Vor -15V
(typical
range
is
between
+
10V and
-
10V) and stops varying with the
dial.
U4
and U1
circuits.
10 Check
that,
as
the
dial
is
rotated
from .004
to 4.0,
U4
pin
13
varies
from
approximately
+
15V
to
+10V.
U4
and U1
circuits.
11.
Check
for nonlinearity
in
the
±
1.25V
triangle at
the emitter
of
Q1
1
near
the
bottom
of the
x
1
K through
x
1
M
ranges.
a.
Associated timing
capacitors
or
C36.
b.
U5, CR6.
c.
Q9, Q10.
12.
Check
frequencies
of
X1K,
X10K
and
100K
ranges.
a.
Adjust R19.
b.
C30, 31
and 32
(trimmed by
C33).
13.
Check frequency and
linearity of
x
1
M
range.
a.
C34.
b.
C36.
c.
C18,
19,
20 and
21.
14.
Check
frequencies
of
x
1,
x
10 and
x
100 ranges.
R86
and
table 6-9.
6-5