POWER SUPPLY
The power supply is designed to operate from
1 00/ 1 1 0 / 1 1 7 / 200/220/234 volts AC. A DC-DC
converter is an available option , providing opera
tion from 1 3 . 5 volts DC. Insertion of the appro
priate power plug into the rear panel re ceptacle
m akes the necessary connections for AC or DC
operation .
When the transceiver is operated from a DC 1 3 . 5
volt power source , using the optional DC-DC
converter, transistors Q320 1 and Q32o2
(T20A6 )
function as a low frequency oscillator, providing
AC voltage at approxim ately 80 Hz to the power
transformer. All of the tube heaters re ceive their
power through the HEATER swit ch on the front
p anel. When the HEATER swit ch is OFF , voltage
is still supplied to the re ceiver section , thus allow
ing continuous re ception with reduced power
consumption . The heaters of the two 6 1 46 B are
connected in series to operate at 1 2 volts DC.
The 1 4 volt AC power delivered from the second
ary winding of the power transform er is re ctified
by D9os and D
g
0
6
(V06 B ) .
Voltage regulators Q 1
( 2 SB6 1 6 ) ,
Q90 1
(78L1 2 ) ,
and Q903
( 2 SA4 9 5 )
st abilize the DC supply at 1 2 volts . The supply
voltage is further stabilized at 8 volts by Q3
(µ PC 1 4 3 0 8 )
for delivery to the counter, AF , and
other units. The 6 volt supply for the VFO is
p rovided through zener diode D908
(WZ06 1
), while
the 5 volt supply for the TTL integrated circuits
is provided by Q505
( 78L05 ) .
T h e power amplifier plate voltage o f +800 volts i s
supplied from the bridge-controlled doubler, locat
ed on the RECT . A UNIT, and consisting of D901 -
D9o4
( 1 00 1 0) .
A C 1 90 volts i s rectified b y D 1 002
( 1 00 1 0) ,
produc
ing 2 1 0 volts for the screen grid supply of the
p ower amplifier tubes. The screen grid voltage for
the driver tube is obtained by rectifying 2 5 0 volts
AC at D 1 001
( 1 00 1 0 ) ,
producing 300 volts. This
voltage is dropped to 1 80 volts by a resistor for
d elivery to the driver tube screen grid .
The 1 20 volt AC power from the transformer
se condary winding is rectified by D 1 003
( 1 00 1 0 )
i n order to obtain - 1 40 volts for the driver and
final amplifier tube grid bias .
-
3 2 -
,
- - -
-
-
-
1
0905
V068
I
GND
h
I
D906
V068
O V
�
1 2 0 V
?
H E ATER
B V
BV
190V
a;i
6V
��
900V
GND
P B - 1967 R E CT. A ( H I- LOW V O LTA G E I U N I T
01002
RIOOG
IODIO
,,.
470 2w
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+
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+
sus�
-
8� -
01003
100 1 0
R I O I O
5.6K
l w
! 6 0 V
IOOV
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QI':
,, .,
I
I
I
I
I
I
I
I
L - - - - - - - - - - - - - - - - - - �
PB - 1 9 6 8 R E C T. Bl
M.
B I AS VOLTAG E ) U N I T
B I A S
( 6 1 4 6 B )