Kenwood TS-990S Service Manual

Also see for SP-990: Instruction manual

Contents

TS-990S45COMPONENTS DESCRIPTIONRef. No. Use/Function Operation/Condition/CompatibilityQ20 Switching Control detect of 10MHz REFinputQ21,22 Switching Power supply SW of 10MHz REFinput circuitQ23 Switching ON when VCO1 operateQ24 Switching ON when VCO2 operateQ25 Oscillate VCO VCO1Q26 Oscillate VCO VCO2Q27 Buffer DDS (IC13) output bufferQ28 Switching Power supply SW of DDS (IC13)output bufferQ29 Switching ON when 1/10 divide of VCOoperateQ30 Ripple fi lter For MLO1 PLL loop fi lterQ31 Switching Power supply SW of DDS (IC13)output bufferQ32,33 Switching Power supply SW of 10MHz REFinput circuitQ34 Amplifi er Operate when internal REF isselectedQ35 Amplifi er Fin AMP of PLL (IC17)Q36 Switching ON when VCO3 operateQ37 Switching ON when VCO4 operateQ38 Oscillate VCO VCO3Q39 Oscillate VCO VCO4Q40,41 Switching Power supply SW of D45, D53Q42,43 Switching Power supply SW of D44, D52Q44 Amplifi er MLO1 VCOQ45 Amplifi er MLO1 VCO outputQ46 Amplifi er PLL (IC18) reference inputQ47,48 Switching Power supply SW of D43, D51Q49,50 Switching Power supply SW of D42, D50Q51 Amplifi er Amplifi er of 10MHz REF outputQ52,53 Switching Power supply SW of D29Q54,55 Switching Power supply SW of D46, D54Q56,57 Switching Power supply SW of D47, D55Q60 Switching Power supply SW of 10MHz REFoutput circuitQ61,62 Switching Power supply SW of D48, D56Q63 Switching Power supply SW of 10MHz REFoutput circuitQ64 Switching ON when 1/4 divide of VCO oper-ate.Q65 Switching ON when 1/8 divide of VCO oper-ateQ66 Switching ON when 1/10 divide of VCOoperateQ68,69 Switching Power supply SW of D39Q70,71 Switching Power supply SW of D40Ref. No. Use/Function Operation/Condition/CompatibilityQ72,73 Switching Power supply SW of D38Q74,75 Switching Power supply SW of D41Q76,77 Switching Power supply SW of D33, D37Q78 Buffer 20MHz VCXO outputQ79 Amplifi er Amplifi es 20MHz signalQ80 Amplifi er DDS (IC26) inputQ81 Amplifi er Amplifi es 40MHz signal for10MHz REF output circuitQ82 Amplifi er Fin AMP of PLL (IC18)Q84 Amplifi er Amplifi es 40MHz signal for DDS(IC26) and PLL (IC2)Q85 Amplifi er Amplifi es 40MHz signal as SUBLO unit referenceQ86 Amplifi er Amplifi es 40MHz signal asSCOPE unit referenceQ88 Switching ON when source of MLO1 is DDSQ90 Switching Power supply SW of IC23Q91 Switching ON when FIL4 of MLO1 operateQ92 Switching ON when FIL3 of MLO1 operateQ93 Switching ON when FIL2 of MLO1 operateQ94 Switching ON when FIL1 of MLO1 operateQ95 Switching ON when FIL5 of MLO1 operateQ96 Switching ON when FIL6 of MLO1 operateQ97 Switching ON when FIL7 of MLO1 operateQ98 Switching ON when source of MLO1 is DDSQ99 Amplifi er MLO1 outputD3,4 Surge protection Protect surge from external10MHz REF input connectorD5,6 VCO frequencycontrol DDS REF VCOD7 Switching ON when external 10MHz REF isselectedD8 Protection ofreverse current PLL (IC2) lock detectD9 Switching ON when external 10MHz REF isselectedD10 Voltage shift Dorop input voltage of IC27D11 Switching ON when external 10MHz REF isselectedD12 Switching ON when source of MLO1 is VCOD13 Detect of signal Detect external 10MHz REFD14 VCO frequencycontrol MLO1 VCO1D15 VCO frequencycontrol MLO1 VCO2D16 Detect of signal Control AGC AMPD17 Switching ON when VCO1 is operateD18 Switching ON when VCO2 is operateD19,20 Switching ON when external 10MHz REF isselected