Operating instructions

CHAPTER
4
THEORY
Section
l.
POWER
SUPPLY
PP-30S/URR
44. Block
Diogrom
(fig.
16)
a.
Operating voltage for the
receiver is
ob-
tained
from
Power
Supply PP-308/URR.
This
unit operates from
a standard 115-volt
60-cycle
line; a 6-, \2-,
or
24-vo1t,
d-c vehicular
storage
battery
i
or
a 90-volt and 1.5-volt dry-battery
source.
Output
voltages are 90
volts
dc
-+3
volts, 1.4
volts dc, and-4.2
volts dc.
b. For 115-volt
a-c operation,
the
line
volt-
age
is
stepped down
by a transformer
and the
lower
voltage is
supplied
to rectifler
CR101
(fig.
18). The
rectified
voltage
energizes relay
K101.
When relay K101 is
energized,
the 115-volt
a-c
line is completed
to the rectifier circuit
associ-
ated with V102,
and
the output
of
rectifier
CR101
is
supplied
to fllament
voltage vibrator
E102. Bias
and hv
(high
voltage)
are developed
by the circuit
associated with
V102.
Filament
voltage is developed
by V104, 8102,
and CR102.
Regulator
tubes V101,
V103, and
V104
main-
tain substantially
constant
output voltages.
c.
For
6-volt, L2-volt,
or Z4-volt
operation,
the input
voltage energizes
vibrator E101,
which develops an alternating
voltage to drive
the
rectifler
circuit
associated with
V102. Rec-
tiflcation, filtering,
and
regulation
are
the same
as
for 115-volt
a-c operation.
E102 also is
energized
by the
input
voltage
(K101
is in-
operative)
and,
in
conjunction with
V104 and
('R102,
develops filament
voltage.
d.
For dry-battery operation,
the
voltages
are
upplied from the batteries to the receiver
through the
power
supply.
28
+5.
H-v
Rectifier, Filoment
Voltoge,
qnd
Voltoge
R.egulotion
Circuits
(fig.
17)
a.
In all
modes
of opera"tion,
except dry-bat-
tery, the
h-v rectifier
develops
the Bf,
bias,
and filament
voltages
for
the receiver. Voltage
regulation
is
usecl to deliver
a constant
output
despite
changes
in input
voltage.
In
the
fol-
lou'ing
analysis,
the circuits
connected
to the
secondary
of transformer T102
(common
to all
modes
of operation)
are discussed in
detail.
Primary
voltage
of
T102 is
cliscussed
in detail
in
the
analysis of
the
different mocles
of opera-
tion
(pars.
46
through 50).
b.
High
voltages
from
the transformer sec-
ondary
are connected to the
plates
of rectifier
tube V102
(type
CK1007)
through hash filters
L111
ancl
L112.
Capacitor C113
is
a buffer
for
the vibrator circuit
associated with the
primary
of
T102
during 6-, l2-, and 24-r'olt
operation
(pars.
47
through 49).
Since each
plate
is
con-
nected
to opposite ends of the transformer sec-
ondary and the center
tap
is returned to
ground
through resistor
R109
(or
resistors R108 and
R109),
tube V102 operates as a conventional
full-rvave rectifier. The
pulsating
dc
is filtered
by capacitor
C114
and
bleecier
resistor R110.
c.
Resistor R108 in the
B-
circuit is shorted
to
ground
through
section 6, rear, of POWER
SELECTOR switch 5101
for
all
mocies
of oper-
ation except
DRY BATTERY,
and resistor
R109 is used to develop bias
for
tubes V7
and
V8 in
the receiver.
For DRY BATTERY
oper-
ation, resistor R10B is adclecì in series with
R109. The
bias
voltage is supplied
to the re-
ceiver
through
pin
8 of
J101.
AGO
3ì34