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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
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