Heathkit SB-401 Assembly Manual page 148

Page 124
8;>
AUDIO
~RF
[9>
CONTROL LINES
[:>
REGULATED B+
DSB - DOUBLE SIDEBAND
SSB - SINGLE SIDEBAND
~B
I / ~
TORL2
V
RF OUTPUT
V96CL6
DRIVER
~~
sse
Vl0
6146
FINAL
AMPLIFIER
Vl1 6146
FINAL
AMPLIFIER
®
,I
RCVR '\
I
HET OSC ,
\ INPUT
I
~
"
RCVR'~ TRCV
LMO -
\ INPUT ..
\
/
TRANS
r-{9>
ALC CIRCUIT
BLOCK DIAGRAM
- -
KEY TONE
OSCILLATOR
ANTI-VOX
AMPLIFIER
T
~ ......... _HIGH
IMPEDANCE
'" RCVR OUTPUT
V13A 1/26J11 V13B 1/26J11
I
-
RELAY RL2
ANT
Vl2C V12A V12B
1/3 6010
r"-~
1/3 6010
r"-;>
1/3 6010
J";-
iJ
TONE ~ ~
AMPLIFIER VOX AMP RELAY AMP
~I
c
-
-
TRANS ~ V8B 1/26AW8
V
HET OSC
rscv
r-~
RELAY RLI
sse
W
~
VS 6EW6
(P'
~
HETEROOYNE
MIXER
/0\
BANDPASS
COUPLER
8.395-8.895 MHz
V6
~i-R7~
LINEAR
MASTER
OSCILLATOR
5 - 5.5 MHz
sse
LMO MIXER
V4 6EW6
sse ~
'(P'
XTAL
FIL TER
3.395 MHz
/ RCVR \,
I BFO
\, INPUT /1
SPKR
A
V8A 1/26AW8
"'_-..JI)
~-----I>
HET OSC
AMPLIFIER
~
_0
TRCV
1---C<JY~
0
TRANS
V1 OA2
VOLTAGE
REGULATOR
V2B V2C
13/ 6AV11 ~ 1/36AV11
USB OR CW
SIDEBAND ~ CATHODE ~
GEN FOLLOWER
V2A
1/3 6AV11
LSB
SIDEBAND
GEN
DSB ~
~
DSB ~ BALANCED DSB
~ MODULATOR ~
TRANSFORMER
1P
(4l CRYSTAL
DIODES
r--... BALANCED
Vl B 1/2 6EA8 ._ ....... - Il:;.' . .J MODULATOR
CATHODE ~
FOLLOWER
Sj, ~
AMPLIFIER
ISOLATION
SPEECH
AMPLIFIER
'\'f'-;-"L_--tI
~r-----------------------------~
V3 6AU6
M'C-~
PHONE ___,~. V1 A
t
/2 6EA8
PATCH v