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1 MODEL 4OO TRANSCEIVER
C,
Operation (Cont)
3 .
4 .
A d d a . 4 T o r . 5 M F . , 2 0 0 v o l t
caPacitor across the key.
This
capacitor rnay be added internally
i f d e s i r e d ,
Switch the PHONE -CW control owe!
t o C W p o s i t i o n . T h e n s w i t c h t h e
Function
Switch to TRANS.
to
t r a n s m i t ,
a n d R E C . t o r e c e i v e .
5.
In{ormation
on a sidetone modifi-
cation for the 400 iB available
on
r e q u e s t .
GENERAL
The following
proceduies
are given in
the order
performed
during the factory
alignrnent
fo! the transceiver,
For
home servicing
only partial
alignment
m a y b e n e c e s s a r y .
R e a d a l l p r o c e d u r e s
carefully
before commenc ing either
partial
or complete
aliSnment.
See
F i g u r e s 4 a n d 5 I o r
c o m p o n e n t p l a c e -
rnent.
Equiplnent
Requi!ed
L
Caliblated
audio freqqency
signal
g e n e r a t o r ,
r a n g e 2 0 0 t o 5 0 0 0 c p s .
2.
500 watt dummy load with output
3.
Vacuum tube voltmeter,
4,
Walsco 2543 coil adjustbent
tool.
5,
Field
str€ngth meter
6.
Calibrated
RF Signal Generator.
P!e -Alignment
Conditions
l .
N e u t r a l i z i n g c a p a c i t o r B C 4 l 3 a e t
t o r n i d - p o i n t a n d C 3 l 6 B e t t o
approxirnately
3/4 turn lrom
futl
cornpres 6ion.
2 .
P e a k l F t r a n s f o r m e r s
f o r m a x i -
rnurn background
noise with AF and
RF gain Iull clockwi8e
(eithe!
bottom or top core adjustrnent).
3,
Loosely,
couple field strength
r n € t e r t o C 3 l ? ( o f f p i n 9 o f V 4 )
with alligator
clip on cerahlc
capacitor
body.
T R O U B L E S H O O T I N G
4.
Transmit bias potentiometer full
counter-clockwise
(maximurn bias).
VFO AMPLIFIER
PLATE
CIRCUIT ALIGNMENT
W i t h V T V M f r o m p i n I o f V 7 , R e c e i v e r
M i x e r , t o g r o u n d , o n - 1 5 v o l t s c a l e ,
and using a Model 410 or 4068 Frequency
Control Unit, adjust Vr'O Amplifier
Plate coils {or peak VTVM heading as
followB:
D .
A L I G N M E N T
A N D
Band
V F O F l e -
VFO Dial
Reading
F r e q u e n c y ( k c )
C o i l
8 0
3 , 8 0 0
L t 0 4
4 0
1 2 , 3 0 0
7 , 1 2 5
L 1 0 3
l 5
r 6 , 0 5 0
L t 0 z
l o
2 8 , 5 0 0
L l 0 l
TRANSMITTER MIXER AND DRIVER
PLN,TE CIRCUIT ALIGNME NT
1,. Rernove screen voltage florn V4 and
V5 by disconnecting orange wire to
telrninal strip irnrnediately adjacent
t o V 5 b a B e . ( P t . A i n F i g . 5 . )
2 . C o n n e c t V T V M a c r o s s P . 4 1 2 , 4 . 7 K
resistor bet$/een pins I and 2 of
terminal strip irnmediately behind
bifilar coil in cry6tal filter,
!ange
- I 5 v o l t s c a l e , ( P o i n t s B a n d C i n
F i g . 5 ) .
t 7
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