Kenwood TS-950S Service Manual

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

TS-950S/SDCIRCUIT DESCRIPTION+ AT controlThe AT band data is decoded by LPF data, and theAT tap is always switched. When the main unit beginstransmission, the VSWR is calculated from the valuesof power and RWM (reverse power}, and the VSWRsignal is applied to the AT unit to display on the SWRmeter and judge whether the AT tuning has beencompleted.1) When AT auto switch is onThe AT unit controls the relay so that signals passthrough the matching circuit, and places the AT controlsystem in standby.The main CPU takes the variable capacitor positionset for the band from preset data, and drives it to thatposition. Even if the band changes, the CPU drives thecapacitors to the preset position stored in memory,and waits for the next operation.2) AT TUNE on by AT autoWhen both AT Auto and AT Tune are pressed at thesame time, the mode is changed to CW, the filter isset to 8.83 MHz 2.7 kHz, 455 kHz 2.7 kHz for trans-mission, and the AT tune mode is set.Since transmit is initiated by AT TUNE, the mainCPU outputs the VSWR signal and waits until the tunecompletion signal (OK signal) arrives from the AT unit.The AT unit enters the auto tune mode, and starttuning automatically.The rotation angle of the variable capacitor is limitedby the variable resistor connected to it. Therefore, ifthe variable capacitor approaches the mechanical limitpigitac unit |(X46-3050-XX) ||of the variable resistor, the motor rotation is reversedtowards the preset side from the detector side, in thesame way as for the preset setting position, and thevariable capacitor position is moved to the other end ofthe variable resistor range, and returned to the detec-tor side. The main CPU continues tuning, and waitsuntil a tuning completion signal arrives.When manual presetting is performed, the motorrotation is switched from the detector side to thepreset side, and the variable capacitor position is movedby potentiometers, R-tune and X-tune at the upperright of the set.3) When the tuning is completedWhen the AT unit outputs a tune completion signal(OK=Low)}, the main CPU updates preset data, makingthat variable capacitor position the new preset value.4) When AT tuning is offWhen AT Auto or AT Tune is released, the AT Tunemode is released. The mode and filter are returned totheir values before AT tuning was initiated.+ Receive bandpass filter selection (RF unit)The RF BPF signal (RBO to RB3) from the digital unitis buffered by Q6 and Q7 of the digital unit, and is thenforwarded to the RF unit. The RF unit obtains RF BPFdata divided into 15 from 4 bits using two sets ofBCD.-to-Decimal decoders. Band data is given in thelist. RF BPF data is 4-bit parallel data.RF UNIT(X44-3100-00)(MHz)bw 4.0~7.0t——* 3.0~ 4.0p— 7.5~10.0FOR SERVICE MANUALSCONTACT:MAURITRON TECHNICAL SERVICESwww. mauritron.co.ukTEL: 01844 - 351694FAX: 01844 - 352554Fig. 35 RF BPF divisionsi! | 225 a8. + ui -O.5~ 1.63. + = $$» 1.6~3.0t,l4 3 =ron. tT > 24.5~30.0loth 2h} apni} 2 21~21.5pm 14.0~14,5fp 10.0 ~ 10.5.j— 21.5~ 245¢S va 18,0~21.0ze ~14.5~18.0|» 10,5~ 14.0wuy oO +05- 70~7-5BANC INFODECODER 41