Kenwood TS-990S Service Manual page 53

Ref. No. Use/Function
IC5 Shift register
IC7 Mixer
Exclusive OR
IC8
gate
IC9 Main RX FM IC
IC10 OP amplifi er
IC11 Multiplexer
IC12 OP amplifi er
IC13 OP amplifi er
Q1 Switching
Q2 Switching
Q3 Switching
Q4,5 Switching
Q6 Switching
Q7 Switching
Q8 Switching
Q9 Switching
Q10,11 Amplifi er
Q12 Switching
Q13 Switching
Q14,15 Switching
Q16 Buffer amplifi er
COMPONENTS DESCRIPTION
Operation/Condition/Compatibility
Q5: PSEL "H" when preselector
is selected (1.7975~29.8MHz)
Q6: PSAMP "H" when preselec-
tor amp is ON (1.7975~29.8MHz/
30~60MHz (only PREOFF))
Q7: LHF "H" when BPF of
30k~522kHz or 522k~1.705MHz
or 35-40MHz is selected
Q8: NRLY "H" when any one
of MBPF5, 7, 9, 11, 12, 13, 14 is
selected
1st receiving mixer (RF
8.248MHz)
Local signal drive circuit
RX FM demodulator
2nd IF amp
Receiver output, FM (AF) and
SSB/AM/CW (IF) changeover
A/2: RX FM noise squelch volt-
age amplifi er
B/2: RX FM AF signal amplifi er
A/2: No used
B/2: MAGC voltage amplifi er
6dB ATT changeover relay (K1)
control (OFF when main 6dB ATT
is selected)
12dB ATT changeover relay (K2)
control (OFF when main 12dB
ATT is selected)
LHF changeover relay (K3) con-
trol (ON when MBPF1 or MBPF2
is selected (LHF is "H"))
Power supply switch of RX14
(ON when main receiver is active
(MRXC is "H"))
LHF changeover relay (K4) con-
trol (ON when MBPF1 or MBPF2
is selected (LHF is "H"))
ON when BPF of
522kHz~1.705MHz is selected
(ON when MBPF2 is "H")
ON when BPF of 30~522kHz is
selected (ON when MBPF1 is "H")
Preselector amplifi er changeover
relay (K5) control (ON when
PSAMP is "H")
Preselector amplifi er
PREAMP1 changeover relay (K6)
control (ON when MPRE1 is "H")
PREAMP2 changeover relay (K7)
control (ON when MPRE2 is "H")
Power supply switch of RX14 for
PREAMP1 and postamp (ON
when MPRE1 or MPRE2 is "H")
Noise blanker input buffer
Ref. No. Use/Function
Q18 Amplifi er
Q19 Switching
Q20 Amplifi er
Q21 Amplifi er
Q22,23 Switching
Q24 Amplifi er
Q25,26 Amplifi er
Q27 Switching
Q28 Amplifi er
Q29 Switching
Q30 Amplifi er
Q31 Switching
Q32 Amplifi er
Q33 Amplifi er
Q34 Switching
Q35 Switching
Q36,37 Buffer amplifi er
Q38 Switching
Q39,40 Switching
Q42,43 Switching
Q44 Switching
Q45 Switching
Q46 Amplifi er
Q47,48 Switching
Q49 Amplifi er
Q50 Switching
Q51 Switching
Q52 Amplifi er
Q53,54 Switching
TS-990S
Operation/Condition/Compatibility
Noise blanker post amplifi er
Power supply switch of RX8
(ON when main receiver is active
(MRXC is "H"))
Pre-amplifi er 2
Noise blanker amplifi er 2
Power supply switch of RX14 for
PREAMP2 (ON when MPRE2 is
"H")
Noise blanker amplifi er 2
Pre-amplifi er 1
Power supply switch of RX8
(ON when main receiver is active
(MRXC is "H"))
Noise blanker amplifi er 3
PREAMP2 changeover relay (K8)
control (ON when MPRE2 is "H")
Noise blanker amplifi er 3
PREAMP1 changeover relay (K9)
control (ON when MPRE1 is "H")
Noise blanker AGC control ampli-
fi er
Noise blanker amplifi er 4
ATT switch (ON when MBPF14 is
"H", except MPRE1 or MPRE2 is
"H")
Audio mute signal is generated
Noise blanker buffer
Audio mute signal is generated
Power supply switch of RX5 (ON
when main receiver is active
(MRXC is "H"))
Power supply switch of FM5 (ON
when FM mode is active (MRXFM
is "H"))
6dB IF ATT switch (ON when
MHFRGC is "H")
10dB IF ATT switch (ON when
M50RGC is "H")
Post amplifi er
Power supply switch of NFM8 (ON
when except FM mode is active
(MRXFM is "L"))
IF amplifi er
Power supply switch of NFM8 (ON
when except FM mode is active
(MRXFM is "L"))
Post amp changeover relay (K10)
control (ON when MPRE1 or
MPRE2 is "H")
IF amplifi er
Blanking switch (OFF when
MBLNK is "H")
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