Integrator Amplifier Board; Digital-To-Analog Board - Wavetek 150 Instruction Manual

4.
R28
and
R30
will be adjusted
later
in
the calibration procedure.
INTEGRATOR AMPLIFIER BOARD
(Board No. 017-105-62)
1.
There
are no adjustments on
this
board
unless
the input
transistors Ql,
Q2, Q3, and
Q4
are replaced. Ql,
Q4
and Q2,
Q3
are
matched
pairs
and
should be
matched
to
less
than
1%
for
source current and
V
be
2.
If
these transistors are replaced,
the
zero
offset
is
set
with
trim
resistor
R17
for less than
5
mv. To
set
zero
offset,
(1)
remove Boards
017-104-63
and 017-106-62;
(2)
place
a
3,
3K, 10%
resistor
from
pin 18
to
pin
7
and
a
0.1 pf capacitor
from
pin 18 to
ground
(pin
11, 12,
13
or
14);
(3)
observe
pin
7
with
a
DVM
or equivalent and select
a
trim
resistor
R17
for
an
out-
put
of
less than
5
mv.
DIGITAL-TO-ANALOG BOARD
(Board No. 017-102-63)
1.
Turn
the
three
frequency switches
to the
remote
position.
(In
the
Model
150,
program
a 000,
equivalent
to
opening
the
8-4-2-
1
frequency
contol
lines
.
)
2.
With
a
voltmeter connected
to
the
summing
node
of the
minus
amplifier
(bussed terminals base
of
Ql), adjust lower
right
potentiometer
for zero
volts
3.
With
a
voltmeter connected
to
the top
end
of
R21,
adjust
R1
to
obtain a
zero reading
less
than
1
mv.
4.
Connect
the
voltmeter
to
the
bottom
of
R21
and
adjust lower
left
potenti-
ometer
for
zero
volts.
5.
Connect
the
voltmeter
to the
bottom
of
R38
and adjust
R25
for
zero reading
less than
1
mv.
6.
Program
a
frequency
of
900
Hz
and
adjust
R37
so that
the
positive half
cycle length equals
the negative
half cycle length
to
within
0.
1%.
This
measurement
is
made
with
the
counter connected
to
the
0. 5
volt
square
wave
output.
7.
Without changing
the
range,
program
090
Hz
by
turning
the
most
signifi-
cant decade
to the
remote
(R) position
and
the
other two decade switches
to 90.
Adjust
R25
so that the positive half
cycle length equals
the
nega-
tive
ha
If
c
VC
le
.
Ad
iust
R15
for a total
ne
r
i
nd
of 11.
11
mqpr.
^
^
—
-
»
8.
Program
a
frequency
of
100
Hz
and adjust
R46
to
obtain
a total
cycle
length
of 10.
00
msec.
5-2