Kenwood TS-950S Service Manual

Also see for TS-950S Digital: Instruction manual Instruction manual Instruction manual Instruction manual Service manual

CIRCUIT DESCRIPTIONThe FM AF signal passes through the de-emphasiscircuit, and is then amplified by the FM AGC amplifierIC3 (uPC1158H2). If the deviation of the ANT input is 3kHz or more, the circuit keeps the audio output con-stant and prevents large changes in volume. The FMAF signal and the AM AF signal detected by D21 andD22 {RLS73} are routed from the FAAF terminal.The AF signa! from the SCAF or FAAF terminal isapplied to the AF unit (X49-3020-00). The AF signalfrom the SCAF terminal is routed differently from thesignal from the FAAF terminal. The signal from theSCAF terminal is processed by the DSP and CW VBTcircuit, and is then applied to the AF amplifier IC7 (a/2).The signal from the FAAF terminal is applied directly tohe AF amplifier 1C7 (a/2).The sub receiver signal passes through buffer am-plifier Q7 (2SK520) and the low-pass filter of the RFunit. The signal is mixed with the sub VCO signal inhe first sub mixer Q8 to Q11 (2SK520), and the outputis converted into the first sub IF signal of 40.055 MHz.The unwanted signal components are eliminated fromthe signa! when it passes through the MCF XF1 with a15-kHz bandwidth. When the monitor is on, the RFransmit signal is applied to the first sub mixer.The signal applied to the IF unit from the SUB IFerminal (CN7) is amplified by Q1 (3SK131), mixed withhe HET signal (50.7 MHz) in mixer Q2 and O3 (2SK520),and converted to the second IF signal (10.695 MHz).This signal is separated into two channels; one is sup-plied to the noise blanker circuit, the other is amplifiedby the second IF amplifier Q5 (8SK131), which alsoacts as a noise blanking gate, and passes through the0.695-MHz crystal filter XF1. The signal is furtheramplified by the second IF amplifiers QQ and Q10(3SK131), product-detected by 1C1 (AN612), and routedfrom the SAF terminal (CN15) as an AF signal.This sub AF signal is applied to the AF unit, where itis separated into two channels; one for sub receptionand one for the monitor. For sub reception, the signalis applied to IC7 (b/2). For the monitor, the signal isrouted to the monitor VR.The main AF and sub AF signals are amplified sepa-rately by IC7, passed through the muting circuit Q8and Q9 (2SD1757K), and are applied to the main andsub AF VR. In the CW mode, the sub AF can also berouted through the AF VBT circuit.The AF signal that has passed through the AF VR ismixed with the signal that has passed through themonitor VR in 1C8 (a/2; NJM4558M). The resultingsignal is amplified and applied to the control unit (X53-3230-00) via the AF terminal (CN11), and amplified bythe AF power amplifier IC7 (uPC2002V) in order todrive the speaker.Filters ratings1$-9505/5DItem RatingNominal center frequency 8.830MHz3dB attenuation +50kHz or more at 8.830MHzGuaranteed attenuation 35dB or more at 9.285MHz (+455kH2}45dB or more at 9.74MHz {+910kHz}Insertion loss 6dB or less ElFormula = 20-log (HERipple 1.0dB or less (within 3dB band)Input and output impedance 3302Ceramic filter (L72-0351-05) (IF unit CF1)Item RatingNominal frequency 10.695MHzCenter frequency deviation Within +200Hz at 6d8Passband width andattenuation bandwidth(minimum loss standard}2.2kHz or more at 6dB+1.5kHz or less at 20dB+2.4kHz or less at 60dBRipple 2dB or lessinsertion loss 5dB or lessGuaranteed attenuation 60dB or more within +40kHzInput and output impedance 1.2kQ+ 5% / BpF + 5%MCF (L71-0249-05) (IF unit XF1)item T| RatingNominal center frequency | 73.05MHzPass bandwidth +7.5kHz or more at 3dBAttenuation bandwidth +30kHz or less at 40dBRipple 1.0dB or lessInsertion loss 3.0d8 or lessGuaranteed attenuation 70dB or more at fo + (500 to 1000) kHz}70dB or more at fo — (200 to 1000) kHzCenter frequency deviation Within £1.5kHz at 3dBInput and output impedance 2kQ+ 10%MCF (L71-0401-05} (IF unit XF2)Item RatingNominal center frequency 8830kHzCenter frequency deviation Within £150Hz at 6d8Passband width +1.3kHz or more at 6dBAttenuation bandwidth +#1,7kHz or less at 20dB+2.5kHz or less at 60dB+3.4kHz or less at 80dBRipple 2dB or lessInsertion loss 6dB or lessGuaranteed attenuation 80dB or more in the range+3.4kHz to +1MHzInput and output impedance 6002 / 15peMCF (L71-0222-05) (IF unit XF3)13