supplied · to the c ounter unit and accessory socket
on
the rear p anel .
The stabilized 8 Volt supply from Q2 is used for
the VCO , XTAL and IF UNITS ; and the stabilized
1 2 Volt supply is used for the FM , VOX, and AF
UNITS , and other circuits as well . The 1 2 Volt
supply is further stabilized by Q 1
( uPC 1 4308 )
to
b.e
supplied to the AF and I F UNITS . A further
portion of the 8 Volt supply from Q2 is stabilized
at 6 Volts by
.
Q 1 8 0 1
(TA7089 M )
to be supplied
to the VFO UNIT .
.
Independent vol tage stabilizers are located in the
MEMORY , COUNTER , AF , FM , and PLL UNITS.
( 2 )
High voltage supply
The power amplifier plate voltage of + 8 00 Volts
DC is supplied from the bridge-con trolled doubler
RECTI FIE R UNIT B consisting of D 1 4 0 1 - D 1 4 1 4
( l OD l O)
and C 1 5 0 1 and C 1 5 0 2 i n PB- 1 7 1 2A.
AC 1 9 0 Volts is rectified by D 1 8 0 2
( 1 00 1 0 )
m
RECTI FIER UNIT C to ob tain 2 1 0 Volts for the
screen grid supply of the power amplifier tubes.
The screen grid voltage is reduced to 1 8 0 · vol ts
for the FM , AM , and FSK m odes.
The plate supply for the driver tube is ob tained
by rectifying 2 5 0 Volt AC by D 1 8 0 1
( 1 0 0 1 0 ) .
The D C vol tage ob tained from the RECTI FIER
C UNIT is dropped to
I
60 Volts by a resistor for
the driver screen grid.
1 2 0 Volt AC from the transformer secondary
winding is rectified by D 1 004
( 1 OD 1 0 )
in the
RECTI FI E R A UNIT
( PB- 1 708 )
to ob tain - 1 40
Volts for the grid bias voltage for the d river and
final amplifier tubes.
r - - - - - - - - - - - - - - - - - - - - - - - �
CW
GND
FSK
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F M
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PB-1708(No. IO·
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)
REC T A
U N I T
17
GND
-37-
NC N C
13.5V(Q2,3 l J4(1 l J4(8)
13
14
16
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Summary of Contents for FT-902DM
Page 1: ...INSTRUCTION MANUAL FT 902DM YAESU MUSEN CO LTD TOKYO JAPAN ...
Page 54: ...YA E SU v 8103 A ...
Page 55: ......
