Circuit
Description—Type
575
be
connected
in
parallel
for
105-
to
125-volt
operation,
or
in
series
for
210-
to
250-volt
operation.
The
three
regulated
supplies
furnish
voltages of
—
150-
volts,
+100
volts
and
+300
volts. The +300-volt
supply
also
has
an
unregulated
output
of
about
+400
volts
for
the
oscillator
tube
in
the
high-voltage
supply for
the
crt.
Reference voltage for
the
—1
50-volt,
full-wave
power
sup
ply is
established
by
a
voltage-regulator
tube
V649.
This
tube,
which
has
a
constant voltage
drop
of
about
85
volts,
is
connected between
the
—1
50-volt
bus
and
the
grid
circuit
of
V644A,
one-half
of
a
difference
amplifier.
The
grid
po
tential for
the other
half
of
the
difference
amplifier,
V644B,
is
obtained
from
a
divider
consisting
of
R662,
R664
and
R666.
The
—150-V
ADJ,
R664,
determines
the
percentage
of
total
voltage
appearing
at
the
grid of
V644B
and
thus
determines
the
total
voltage
across
the
divider. When
this
control
is
pro
perly
set,
the
output
voltage
is
exactly
—
150-volts.
The
operation
of
the
circuit
can
be
explained
by assuming
the
output
voltage
tends
to
change.
For
example,
assume
the
loading on
the
supply
tends
to
make
the
output
voltage
go
more
negative.
The
voltage
at
the
grid
of
V644A
will
go
negative
the
same
amount as
the
output,
since
the
voltage
across
the
voltage-regulator
tube
is
always
constant.
The
voltage
at
the
grid
of
V644B
will
go
negative
only
a
pro
portionate
amount,
however,
since
this
grid
obtains
its
volt
age
from
the
divider, an
error
voltage
will
then
exist
between
the
two
grids
of
the difference
amplifier,
which
will
be
in
a
direction
to
make
less
current
go
through
the left
side
and
more
current
through
the right
side.
The
voltage
at
both
the
plate
of
V644B
and
the
grid
of
will
then
go
in
the
negative
direction,
which
will
cause
the
voltage at
the
plate
of
V657
to
go
in
the
positive
di
rection.
The
change
in
voltage
at
the
plate
of
V657,
which
will
be in
a
direction
to
compensate
for
the
change
in the
output
voltage, is
coupled
through
the
rectifier
to
the
output
and
forces
the output
voltage
back
to
its
established
value
of
—150
volts.
C644
and
C655
improve
the
ac
response
of
the
feedback
loop,
thereby
increasing
the
response of the
circuit
to sudden
changes
in
output
voltage.
The
+100-volt
supply
uses silicon
rectifiers
in
a
full-wave
bridge
circuit.
Reference
voltage
for
this
supply
is
obtained
from
the
regulated
—150-volt
supply.
The
voltage divider
R636-R638
establishes
a
voltage
of
essentially
zero
at
the
grid
of
V624.
(The
actual
voltage
at
this
grid
is
equal
to
the
bias
required
by
the
tube).
If
the
loading
should
tend
to
change
the
output voltage,
an
error signal
will
exist
at
the
grid
of
V624.
The
error signal
will
be
amplified
and
inverted
in
polarity,
and
will
appear
at
the grids
of
the
parallel
cath
ode-followers
V627A
and
V627B.
The
cathodes
will
follow
the
grids
and
will
force
the
output
voltage
back
to
its
estab
lished
value
of
+100
volts.
C630
improves
the
response
of
this
circuit
to
sudden
changes
in
output
voltage.
A
small
sample
of
the
unregulated
bus
ripple
will
appear
at
the
screen
grid
of
V624
through
R624. The
ripple
signal
appearing
at
the
screen
(which
acts
as
an
injector
grid)
will
produce
a ripple
component
at
the grids
of V627
which
will
be
opposite
in
polarity
to
the
ripple appearing
at
the
plates
of
V627.
This
tends
to
cancel
the
ripple
at
the
cathodes,
thereby
reducing
the
ripple
on
the
100-volt
bus.
The
same
circuit
also
improves
the
regulation
of
the supply
in
the
pre
sence
of
line-voltage
variations.
The
operation
of
the
regulator circuit
in the
+300-volt
supply
is the same
as
that
in
the
+100-volt
supply.
CRT
Circuit
A
30-kc
Hartley
oscillator
circuit furnishes
energy
for
the
two
half-wave power
supplies
that
provide
accelerating
po
tentials
for
the
crt.
The
main
components
of
the
oscillator
circuit
are
V810
and
the
primary
of
T801
tuned by
C809.
V812
supplies
about
+2400
volts
for
the
post-deflection
accelerating
helix.
V822
supplies
about
—
1850
volts
to
a
divider
to
provide
the
grid
and
cathode
potentials.
The
other
end
of
the
divider
is
connected
to
the
regulated
+300-
volt
bus.
The
—1700
V
ADJ control R816
determines
the
total
resistance
in
the
divider
and
hence
the
total
voltage
across
the
divider.
When
this
control
is
properly
set,
the
voltage
at
the
test
point
will
be
exactly
—
1700
volts.
The
accelerating
potentials
are
kept
constant
by
regulating
the
supplies
by
comparing
a
sample
of
the negative
high
voltage
to
the
regulated
—
150-volt
supply.
This
sample
of
the negative high
voltage
is
obtained
from a
tap
on
the
di
vider
(the
junction of R816 and
R818)
and
is
applied
to
the
grid
of
an amplifier
V804A.
The
cathode
of
this
tube is
con
nected
to
the
—150-volt
regulated
supply.
If
the
negative
supply
tends
to
drift,
an
error
signal
appears
at
the
grid
of
V804A.
The
error
signal
is
amplified
by
V804A
and
V804B,
and
produces
a
change
in
the screen
voltage
at
the
oscillator
tube.
This
varies
the
amplitude
of the oscillator
output
in a
direction
to
compensate
for
the
change
in
output
voltage.
The
positive
high-voltage
supply
is
regulated
indirectly,
as
the
output
of
both
supplies
is
proportional
to
the
oscillator
output.
3-12
®@2
Summary of Contents for 175
Page 4: ...VWTICM OINltAlO TRANSISTOR CUM TRACfR UB l COUlClO r hokizoniai VCKIJ O lUnK Hix M Type 575 z ...
Page 6: ...NOTES ...
Page 26: ...NOTES ...
Page 48: ...NOTES ...
Page 54: ...Recalibration Type 575 C706 Fig 5 3 Left Side View 5 6 ...
Page 56: ...NOTES ...
Page 100: ...INPUT AMPLIF1E ...
Page 104: ...TYPE 575 TRANSISTOR CURVE TRACER ...
Page 108: ...OSCILLATOR 4OOV UNREG TYPE 575 TRAN5I5TOR CURVE TRACER AB ...
Page 115: ... 300 ...
Page 119: ...Type 175 Tent S N 570 PARTS LIST CORRECTION Change to Q233 151 0137 00 2N21U8 MIO 298 1165 ...