Power Supply - Yaesu FT-901DM Instruction Manual

is amplified by 0 2 8 0 5 and 02 8 0 6 (both
and 02 8 0 7 ( 2 SC372Y),
swi tch to the PLL UNIT (replacing the VFO
signal ) .
02 8 1 3 ( SN74 LS OO N )
generate timing pulses t o set or reset the counter.
The 200 Hz sign al delivered from 0 2 8 1 1 is ampli­
fied by 02 8 0 8
(MPSA 1 3 )
and D2 8 0 5 (b o th 1 S 1 88FM)
voltage to be used for operational amplifier 0 2 8 2 0 .

POWER SUPPLY

The p ower supply is desigped t o operate from
either 1 00/ 1 1 0/ 1 1 7 / 2 00/2 20/ 2 3 4 Volts AC 5 0/
6 0 Hz (all models) or 1 3 . 5 Volts DC with the
DC-DC converter unit (built-in on the FT-9 0 1 DM ,
optional on o ther models ) . Insertion o f the ap­
propriate power plug into the rear panel receptacle
makes the necessary c onnections for operation
from either AC or D C power sources.
When the transceiver is operated from a 1 3 . 5 Volt
DC power source, transistors 0 3 2 0 1 and 0 3 2 0 2
(b oth T20A6) function as a low frequency oscil­
lator to provide AC voltage at approximately 8 0
Hz t o the power transformer. All o f the tub e
heaters receive their power through the HEATER
switch on the fron t panel. With the HEATER
switch in the OFF p osition, voltage is still supplied
to the receiver section, thus allowing con tinu ou s
reception with reduced power consumption. The
heaters of the two 6 l 46B are c onnected in series t o
operate at 1 2 Volts DC.
Low voltage supply
( 1 )
AC 1 1 . 5 Volt power delivered from the second ary
winding of the transformer is rectified by D 1 0 0 1
and D 1 0 0 2 (V06B) in the RECTIFIER A UNIT
(PB- 1 708 ) to p rovide the transistor supply voltage .
The rectified DC voltage is supplied through pin
8
and pin 1 o f the AC p lu g to pin 1 of the power
receptacle which is connected to the DC power
DC
supply lin e . In the
the power cord is directly supplied to pin 1 o f
the power recep tacle . The D C voltage i s filtere d
through CH 1 0 0 1 , C 1 0 0 1 , and C 1 0 0 2 , and fed t o
the voltage stabilizer 0 2
Q 3 (µPC 1 43 1 2) (+ 1 2V) ; 1 3 . 5 Volt power is als o
JF-1 03 3 B )
and fed through a diod e
a n d 02 8 1 4 ( SN74LS04N )
and rec tified by D 2 8 0 4
t o produce a minus
mode, the DC voltage from
(uPC l 4308) ( 8 V) and
supplied t o the counter unit and accessory socket
on the re ar panel.
The stabilized 8 Volt supply from 02 is used for
the VCO , XTAL and I F UNITS ; and the stabilized
1 2 Volt supply is u sed for the FM , VOX, and AF
UNI TS , and other circuits as well. The 1 2 Volt
supply is further stabilized by 0 1
be supplied to the AF and I F UNITS .
p ortion o f the 8 Volt supply from 02 is stabilized
at 6 Volts by 0 1 8 0 1
to the VFO UNIT.
Independent vol tage stabilizers are located i n the
MEMORY , COUNTER , AF , FM , and PLL UNI T S .
voltage supply
( 2 ) High
The power amplifier plate voltage of +800 Volts
DC is supplied from the bridge-controlled doubler
RECTI FI ER UNIT B consisting of D 1 4 0 1 - D 1 4 1 4
( 1 00 1 0) and C 1 5 0 1 an d C 1 5 0 2 in PB- 1 7 1 2 .
AC 1 9 0 Volts is rectified by D 1 8 0 2
RECTI FIER UNI T C to ob tain 2 1 0 Volts for the
screen grid supply of the power amplifier tub e s .
The screen grid voltage is reduced to 1 8 0 V olts
for the FM , AM , and F S K modes.
The plate supply for the driver tube is ob tained
by rectifying 2 5 0 Volt AC by D 1 8 0 1
The D C vol tage ob taine d from the RECTI F I ER
C UNIT is dropped to 1 6 0 Volts by a resistor for
the d river screen grid.
1 20 Volt AC from the transformer second ary
winding is rectified by D 1 0 0 4
RECTI FIER A UNI T
Volts for the grid bias vol tage for the driver and
final amplifier tubes.
.
-3 6 -
(uPC 1 4308 )
A
further
(TA7089M ) to be sup p l ied
( 1 00 1 0 )
( 1 00 1 0 ) .
( 1 00 1 0 ) in the
(PB- 1 708 ) to ob tain - 1 4 0
to
in