VFO UNIT
The VFO UNIT is very critical in its adjustment.
As well , this is not an area which should ever
require alignment . Questions regarding drift , et c . ,
usually can be traced to other areas o f the trans
ceiver (instability in the supply voltage, etc. ). For
this reason, all cases regarding VFO rep air should
be referred to an experienced service technician .
The following components are of interest from a
service standpoint :
TC80 1 i s the band set trimmer.
TC802 is the VFO level set trimmer.
To confirm proper VFO injection , conne ct the
VTVM to the VFO output . Adjust TC802 for a
reading of 1 00 m V .
B A N D C RYS T A L
1 60m
x
6 0 1
8 0 m
x
6 0 2
40m
x
6 0 3
20m
x
6 0 4
1 5m
x
6 0 5
l O m A
x
6 0 6
l O m B
x
6 0 7
l O m C
x
6 0 8
l O m D
x
6 0 9
JJY/WWY
X 6 1 0
SELECT
SWITCTH
BOARD
V C so 1
T C so 1
FREQUENCY
TRAN S F O R M E R
1 5 . 9875MHz
T60 1
17 . 9875
T602
2 1 . 4875
T603
28 . 4875
T604
35 . 4875
T605
42 . 4875
T606
42 . 9875
T607
43 . 4875
T608
43 . 9875
T609
1 9 . 4875
T6 1 0
Table 6
NB-FIX UNIT
Fixed Channel Frequency Alignment
When the optional fixed channel crystals are b eing
used, they may be placed exactly on the corre ct
frequency by adjusting TC201 (for channel 1 ) and
TC202 (for channel
2).
Confirmation of the correct
frequency m ay be m ade with an external receiver
or by loosely coupling a probe from the frequen cy
counter to the transmit ter output . A I -turn loop
is usually sufficient to provide indication on the
counter.
PREMIX LOCAL UNIT
Premix Local Alignment
1 .
Conne ct the RF prob e of the VTVM to pin 1
of MJ3 .
2 .
Refer to Table 6 , and adjust the appropriate
transformer for a level of 3 00 m V for each
band and crystal , as shown in the table .
PREMIX UNIT
For this alignment , a wideband (not peak) sweep
generator, as well as an oscilloscope , should be
used.
1 .
Press the EXT sele ct swit ch. Apply 5 .0 - 5 . 5
MHz sweep output t o the VFO output
terminal at the rear apron external VFO jack.
Connect a high-impedan ce probe o f an oscillo
scope to J 3 0 1 .
2 .
Adjust the transform ers shown i n Table 7
for a flat response across the entire p assban d .
If you have never adjusted a bandpass filter
previously , this may take some practice .
Perform the adjustments on each band , ac
cording to the chart .
B A N D
T RANS-
PA S S BAND
FORMER
160m
T 3 0 1 , T J 0 2
1 0 . 4 - 1 1 . 0
(
M H z
)
80m
T 3 o 3 , T3o4
1 2 . 4 - 1 3 . 0
40m
T 3 o 5 , T3o6
1 5 . 9 - 1 6 . 5
20m
T 3 0 1 , T J o s
22 . 9 - 23 . 5
1 5 m
T 3 o 9 , T 3 1 0
29 . 9 - 3 0 . 5
l O mA
T3 1 1 , TJ32
36 . 9 - 39 . 0
JJY/WWV
TJ 1 3 , T3 1 4
1 3 . 9 - 1 4 . 5
Table 7
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