Table of Contents
Advertisement
Table
6-2.
Power
Supplies
and
Generator
Loop
(Continued)
Indication:
Fuse
blown,
no
power
indication or
no
outputs.
7.
Check
If
Faulty,
Check
Check
U7
pin
1
4
for
+5
Vdc and
U7
pin
1
3
for
-
5 Vdc.
a.
Q4, Q3, U2.
b.
Excessive
loading;
use
board jumpers
to
isolate
cause.
8.
Check U4
pin
1
3
for
a
dc
shift
from approximately
+
1
0V
to
+
1
5V
as
the
frequency
dial
is
rotated
from
4.0
to
.004.
Check U6
pin
8
or
a
dc
shift
from
-
10V
to
-
15V
as
the
frequency
dial
is
rotated
from
4.0
to
.004.
Go
to
table
6-7.
9.
Check anode
CR6
for
approximately
+3.5
Vdc.
Go
to
table 6-10.
1
0.
If
emitter
Q1
1
has
a 4 kHz,
±
1
,25V
triangle,
go
to
table
6-3.
1
1
.
Check
for
the
same
voltage
at
the gate
of
Q9
as
at
the emitter
of
Q1
1
within saturation
limits of
the
amplifier.
Q9
-
Q1
1
and
associated
circuitry.
12.
If
the voltage
at
the emitter
of
Q1
1
is
> +
1
.25V,
check cathode CR1
for
approximately
-
2.5V.
If
the voltage
at
the emitter
of
Q1
1
is
< -
1
.25V,
check cathode
CR10
for
approximately
+
2.5V.
U7,
Q7
and
associated
circuitry.
13.
Check
U5.
Table
6-3.
Output
Circuits
Indication: Function outputs
missing
or
clipped
when
TTL sync output OK. Problem
with triangle
waveform.
Check
If
Faulty,
Check
1.
Set controls
to
initial
positions
(refer to
paragraph
6.4).
Check
for
normal
operation.
2.
Check
emitter
Q1
1
for
a
4
kHz,
±
1
,25V
triangle.
Go
to
table
6-2.
3.
Select
triangle function, rotate
AMPLITUDE
ccw, and
check
U13
pin
10
for
a
±1
,25V
triangle.
a.
Ri
1
4,
R1
1
2 adjustments.
b.
U13,
c.
SW13.
4.
Rotate
AMPLITUDE cw
(MAX),
DC
OFFSET
to
OFF, and check 50Q
OUT
(HI) for
a
20V
p-p
(open
circuit) triangle.
a.
Output
amplifier
circuit.
b.
E15,
E16
wiring.
5.
Check
for
excessive
discontinuities
at
the
triangle
peaks
near
the
bottom
of
a
frequency range
(other
than
x
1
to
x
1
00).
a.
U5.
b.
SQR
signal
at
cathode
CR10
not
±2.5V.
6.
Check
for
nonlinearities
in
the
triangle
slopes near
the
bottom
of
a
fre-
quency
range
(other
than
XI
to
X100).
a.
Associated
timing capaci-
tor
or
C36.
b.
U5,
CR6.
c.
Q9, Q10.
7.
Check
for
a
waveform symmetry
problem.
Go
to table
6-8.
6-3
Advertisement
Table of Contents
