Kenwood TS-830S Service Manual page 3

b w
INTRODUCTION
The T S - 8 3 0 s 1 s a dual conversion transceiver using t w o in-
termediate frequencies, 8 . 8 3 M H z and 4 5 5 kHz. However.
this differs from transceivers of the 'so called Colllns type(such
as the TS-520) in that the bandwidth of both intermediate
frequencies
IS
narrowed for perforrr~ing VBT operation
Therefore, the T S - 8 3 0 s can basically be considered a single
conversion transcelver wlth an 8 . 8 3 M H z IF
Operation of the transmitter is opposite In process to the
receiver AN SSB signal generated at 4 5 5 kHz
IS
con-
. - - .
-
.
-
-. -.
verted to 8 . 8 3 MHz, and is then m ~ x e d with the PLL (local 0s-
Table 2 . Crystal filter (L71-0222-05)
YK88S1 (IF unit, X F I )
cillator output) to produce the final transrriission frequency
Item
Center frequency l o
Center frequency dev~ation
Pass bandw~dth
Attenuation bandwidth
Ripple
Loss
Guaranteed attenuation
( l o + l O k H z t o ! o + l MHz)
Input and output
impedance
The circuitry is hybrid with vacuum tubes used only in the
drlver
(
12 BY7A) and flnal-stage power amplifier ( 6 146B's)
The PLL c i r c u ~ t generaies a heterodyne frequency for each
band, a counter reference signal, and a 2 5 kHz marker, all
Ratlng
8831.5 kHz
W ~ t h ~ n r 2 5 0 H z at 6 dB
+ 3 0 kHz
or
more
a t 6
dB
f 6kHz or less at 6 0 dB
?
10kHz or less at 8 0 dB
2 dB or less
3 dB w ~ t h i n t 2 dB
.
8 0 dB or more
600!1//15PF
from a single crystal oscillator
The T S - 8 3 0 s Incorporates an IF SHIFT circuit, VBT, VOX
Table 3. Crystal filter (L71-0223-05)
YK-88A (IF unit. XF2)
(also used for CW seml break-in), slde tone circuit, RF speech
processor, -transmiss~on monitor clrcuit, nolse blanker, XTAL
calibrator, notch filter, and etc.
RECEIVER CIRCUIT
The signal comlng from the antenna is routed through step-
up antenna coil via an RF ATT switch and IF trap. M O S FET
(Q1 3 S K 7 3 ) amplifies this slgnal Approximately 9 dB of
negatlve feedback is applied to -the RF amplifier t o reduce
nolse and expand the amplifiers range of linear
operation
The signal passes through a buffer amplifier ( Q 2 2SK125)
and is m ~ x e d with the PLL VCO output by a balanced mixer
((23, Q 4 2SK125) The signal is n o w converted t o the first
lntermedlate frequency, 8 . 8 3 MHz. Entering the IF unit, this
signal is a m p l i f ~ e d by Q1 (2SK125), passes through ceramic
filter CF1 and the N B gatlng circult, and is applled to crystal
filter XF1 whose center frequency is 8 . 8 3 MHz. The signal
leaving the crystal filter is mixed wlth the VBT local oscillator
output at 8 . 3 7 5 M H z by a balanced mixer (Q2, 0 3 3SK73)
where it
IS
converted to the second Intermediate frequency,
4 5 5 kHz. The signal then passes through ceramic filter CF2
whose center frequency is 4 5 5 kHz, and is amplified by 0 4
(3SK73) It then
IS
fed to the notch circuit, Q 5 through Q7
(2SC18 1 5 ) After being amplified by Q 8 (3SK73), it is
demodulated t o an audio srgnal by the product detector
( D 2 0 - - D 2 3 , I N 6 0 X4)
In the AF unit, the audio s ~ g n a l is amplified by Q3
(2SC2240), passes through the AF GAIN control and after
belng arnpllf~ed by the power amplif~er Q 4 ( H A 1 3 6 8 R ) .
drives the speaker
Table 4 . Ceramic filter (L72-0314-15)
CFJ455K5 (IF unit, CF2)
L
Item
Center frequency fo
3 dB bandwidth
30 dB bandwidth
Input level (at 8 0 dBp output)
Ripple (within 3 dB handwidth)
Spurious response
Input and output impedance
TRANSMITTER CIRCUIT
Item
Center frequency
6 dB bandwidth
- -
6 0 dB bandw~dth
Rating
8.830 MHz
fo
f
5 kHz or more. total 25 kHz
or more
1 0 0 kHz or less
93.5 dB or less
1 dB or less
20
dB or more
within fo
+
1 . 5 MHz
330R
Audlo input picked u p by the m ~ c r o p h o n e comes to the IF
unit and
I S
a m p l i f ~ e d by Q 1 9 - 2 1 The input circuit adapts
t o any m ~ c r o p h o n e impedance of from 5 0 0 ohms to 50k
ohms. This a m p l ~ f ~ e d output
IS
converted t o a DSB signal by
the balanced modulator D 2 9 - 3 2 ( 1 N 6 0
X
4 ) , passes through
buffer amplifier Q 2 2 (2SK1 9), a 455kHz ceramic filter, and
the output appears as a SSB slgnal This signal passes either
buffer amplifier Q 2 3 ( 2 S C 1 8 1 5 ) , or the speech processor
consisting of Q 2 4 , 2 6 , and 2 7 Then the first transmit mixer
( Q 2 8 3SK73) converts thls t o an 8 . 8 3 M H z SSB signal
After passing the 8 . 8 3 M H z crystal filter and being amplified
by Q 2 9 (3SK73), the signal is applied t o the second transmit
mixer in the RF unit. This. double balanced mixer (Q6,
Q 7 3SK73), mlxes the slgnal w i t h the PLL VCO output to
convert to the final Transmlt frequency Output is a m p l i f ~ e d
by the driver tube (V1 12BY7A) and then by the final power
amplifier ( t w o 6 1 4 6 B ' s ) and is applied to the antenna via a
T-matching network.
Guaranteed attenuat~on
6
dB or less
Guaranteed attenuat~on 6 0 dB or more
( l o
+
100 kHz1
impedance
LOSS
6 d~
Table 5. Ceramic filter (L72-0322-05)
Input and output ~mpedance 2 k ! 2
CFW 456.5HT (IF unit, CF 3 )
Item
Center frequency l o
6
dB bandw~dth
50 dB bandw~dth
R~pple ( i o + 2 kHz)
Rat~ng
455 kHz
+
0 2 kHz
2 7 kHz or more
4 5 kHz or less
PLL CIRCUIT
The PLL s ~ g n a l is synthesized from the VFO, CAR, and VCO
outputs. The T S - 8 3 0 s .employs a programmable divider in
the PLL t o synthesize the heterodyne frequency from the
standard reference oscillator frequency This simplifies the
Rating
456.5 kHz
t
3 kHz or more
+9 kHz or less
2 dB or less
PLL circuitry by eliminatin'g the need for a separate HET
XTAL for each band
- - -
Table 1. Ceramic filter pair (L72-0310-05) 2 pcs.
SFA8.83MF combined (IF unit, C F 1 A & B)