Kenwood TS-950S Service Manual

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

TS-9505/SD30CIRCUIT DESCRIPTION3) Timing for semi-break-in operationGeneration of the TXB signal when the key isdepressed —When the key is down, the SS line goes high insimilar to the manner described for full break-in.During semi-break-in operation, pin 5 of analog switch1C3 goes high, and pins 4 and 3 conduct. Q7 is turnedon via D26, pins 4 and 3 of IC3, and D10 from the SSline; and CSS is grounded to notify the microprocessorof the start of transmission. —TXB is generated from CTXB via D16 from SS.CKY and transmission hold circuitThe KYB signal produced by depressing the keytriggers the A input pin of one-shot multi-vibrator IC10,and the Q output is high for a period of time.Since pin 5 of analog switch IC3 is high, pins 4 and 3conduct. Q7 is turned on via D10, pins 4 and 3 of IC3,and D10 from the © output; and the CSS line isgrounded. CSS is held low for the time determined bya time constant of the one-shot multi-vibrator, or thetime constant for semi-break-in.The KYB signal, having passed through D11, enterspin 11 of IC1, passes through the time constant circuitcomposed of R51, C38, and R52, and is applied to pin1 of IC2’s NAND gate from the IC1 inverter D21.Pin 2 (SS) of IC6 goes high through D27 and pins4and 3 of |C3 while the O output of IC10 is high. The SSline is held high while IC10 is retriggered by the keyingsignal.Therefore, pin 2 of IC6’s NAND gate is high. The Ainput of the [C10 one-shot multi goes high unless SSchanges 10 ms after SS is triggered for the first time Qgoes high. Pin 1 of IC6 goes high, and pin 10 of IC5and pin 2 of {C2 go high.Therefore, the output of pin 3 of IC2, the signalkeyed by KYB is generated from pin 2 of analog switchIC4 with a 5 ms delay time and becomes the CKYsignal. When the hold time of the 1C10 one-shot multi-vibrator has elapsed after the key is released, the Q pingoes low, and SS goes low, returning the unit to re-ceive.4) VOX operationWhen one-shot multi-vibrator ICQ is triggered by theoutput of the VOX module (X59-1080-01) of the AF unit(X49-3020-00), the Q line output goes high and is con-nected to the control unit (X53-3230-00) by a harness.Q8 is turned on through pins 8 and 9 of analog switchIC3 from connector CN4 VOXQ pin of the control unit,and the SS line is grounded. Subsequent operationsare the same as for manual standby.FOR SERVICE MANUALSCONTACT:MAURITRON TECHNICAL SERVICESwww. mauritron.co.ukTEL: 01844 - 351694FAX: 01844 - 352554Fig. 20 Semi-break-in timing chart