Kenwood TS-990S Service Manual

Also see for SP-990: Instruction manual

Contents

TS-990S30CIRCUIT DESCRIPTIONFig. 32 13.8 V power supply and 5 V backup power supplyAC/DC50V output(Rating 12A)AC/DC power supplyAC/DC13.8V output(Rating 13A)AC/DC5V output(Rating 0.5A)SW14SW8V DCDC5V DCDC3.3V DCDCPSC33PSCACDC SW50V SW3.3V RegReset IC14V14STo Final PCB (EH 4pin)14S5VTo Link PCB (FFC 40pin)33S14V5VTo Control PCB (PH 8pin)5B33STo Digital PCB (PH 9pin)5V33V14S8VTo Local PCB (PH 10pin)14S8VTo Scope PCB (PH 3pin)14S8VTo RX PCB (PH 7pin)RS-232C14STo Display PCB (EH 2pin)Analog MPX/BKCSWDC-DC PCB14V14S-12V-12V6-8. Interface CircuitThe interface circuit is connected to the control unit viathe CN35 connector on the scope unit. The scope unit hasa level shift circuit to shift voltage because it uses a 3.3 Vpower supply.7. DC/DC Converter Circuit7-1. 13.8 V Power Supply and 5 V Backup PowerSupply1. The AC/DC power supply inputs 13.8 V (13 A) along witha backup of 5 V (0.1 A) into the DC-DC PCB (X43-322A/3). The power supply input from the 13.8 V input ter-minal is distributed to each PCB through the followingpaths.1) 14 V system: 13.8 V input is supplied to the FINAL PCB(X45-388 A/2), CONTROL PCB (X53-452), and CAT-ION DC-DC (APPLI) PCB (X43-322 C/3).2) 14S system: 13.8 V input is supplied through the FETswitch to the FINAL PCB, LINK PCB (X43-322 B/3),DSP PCB(X53-453), DISPLAY PCB (X54-385 A/6),PLL (MAIN LO) PCB (X50-322), PLL (SUB LO) PCB(X50-323), SCOPE PCB (X42-343 A/10), and RX PCB(X55-313 A/2).3) 8 V system: 8 V generated from the 13.8 V input intothe DC/DC converter is supplied to the PLL (MAIN LO)PCB, PLL (SUB LO) PCB, SCOPE PCB, RX PCB, andTX-RX PCB (X57-827 A/2).4) 5 V system: 5 V generated from the 13.8 V input into theDC/DC converter is supplied to the LINK PCB, CON-TROL PCB, and DIGITAL PCB (X46-339).5) 3.3 V system: 13.8 V input into the DC/DC converter issupplied to the DIGITAL PCB, the RS-232C driver inthe DC-DC PCB, and the analog multiplexer circuit. Fur-thermore, 13.8 V input is supplied via the FET switchfrom the 13.8 V input, to the LINK PCB and CONTROLPCB.2. The power supply input from the backup 5 V input terminalis supplied through the CONTROL PCB and the reset ICand 3.3 V series regulator on the DC-DC PCB to the BKCdetection circuit on the DC-DC PCB.3. The DC-DC PCB supplies a variety of control signals tothe BKC circuit on the CONTROL PCB, RS-232C driver,external AT, KEY PAD, and LINK PCB.