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Sweep Amplifier
The
sweep
amplifier
converts
the sawtooth
output
of
the
sweep
generator
into push-pull
Output
at low
impedance
at the level
required
to sweep
the
beam across the crt-tube screen.
The amplifier gain can be increased by a factor
of five for sweep magnification. The horizontal-
positioning
control
operates
on
this
stage.
Unblanking
The
multivibrator
generates
the
positive-
going unblanking pulse at the same time itturns
on the sweep
generator.
The
positive pulse is
transmitted
by means
of two cathode followers
through
a floating high-negative-voltage supply
to the control grid of the crt tube.
POWER
Plate and Heater
Power
The
60-cycle
117/234-volt transformer
has
five separate
high-voltage windings.
AC output
from each winding is rectified through separate
bridge-connected full-wave selenium rectifiers.
Rectified
dc output
is filtered
with
capacitors
and
regulated
by
means
of
series-regulator
tubes.
Four positive-voltage supplies giving 100
volts,
225 volts, 350 volts and 500 volts, are
all referred
to the negative 150-volt supply for
regulation.
The negative 150-volt supply is re-
ferred to a gas regulator tube.
Seven
heater
windings
on
the same
trans-
former furnish heater voltage to all tubes using
ac
in the main
unit and the plug-in units.
Two
of these windings are also used to supply a sel-
enium bridge rectifier which supplies dc voltage
for the delay-line driver tubes.
External Sweep Amplifier
The
external
sweep
amplifier
provides
a
means
of
using
external
sweep
voltage.
It
includes a fixed attenuator and an adjustable at-
tenuation control.
Choice of internalor external
sweep can be made by means of the HORIZONTAL
DISPLAY
switch.
The
sweep
magnifier
must
be used
with external
sweeps.
Calibrator
The
calibrator
has
no
internal connection to
the
vertical
amplifier
system.
It consists of a
symmetrical
multivibrator
with
a cathode-fol-
lower
output tube
whose
cathode
resistor
is a
calibrated voltage divider.
SUPPLY
Cathode-Ray Tube High-Voltage
A 60-ke
vacuum-tube
oscillator has the pri-
mary of a step-up transformer for its oscillator
inductance.
A sample of the rectified secondary
voltage
is compared
to a stable dc source, and
the difference
is kept constant by an electronic
circuit that
adjusts
the oscillator amplitude of
oscillation
in the direction to reduce any change.
A voltage
tripler vacuum-tube rectifier pro-
vides positive 8650 volts for the post-deflection
acceleration
electrode of the crttube.
Twonega-
tive supplies, insulated from each other, supply
the crt-tube
cathode
at -1350 volts and control
grid
at -1450 volts.
The control-grid supply is
free
to
assume
a
voltage
1550
volts
more
negative than its positive terminal. The positive
terminal is raised more positive by the positive
unblanking
pulse
and the negative terminal and
ert-tube
control
grid therefore
also follow the
same positive pulse 1550 volts below.
VERTICAL-DEFLECTION SYSTEM
GENERAL
In
the
Type
531, the de-coupled,
push-pull
main Vertical Amplifier provides the necessary
gain
to drive the Delay
Line
and the vertical
deflection
plates
of the crt.
The main units of
the Vertical
Amplifier
in Serial
Numbers
101
through
7600
are the Input Amplifier and Delay
Line
Driver stage, V508
and V509;
the Delay
Line
Output
Cathode
Followers,
V558A
and
PAGE
3-2
V558B,
the Output
Amplifiers, V570
and V580
and the Output Cathode
Followers, V606A and
B,
The
other
circuits are the Internal Trigger
Amplifier, V527, the Internal-Trigger Cathode
Follower,
V535A
and
the Vertical-Signal-Out
Cathode Follower, V535B.
In Serial
Numbers
7601
and up, the Vertical
Amplifier
Main
Units
are
the
Input
Ampli-
fier
stage V504
and V524,
the Driver Cathode
531/541—CI RCUI T DESCRIPTION
"S
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