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                             K E N W O O D
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                        Kenwood Service Centers

   Kenwood Service Corporation             Kenwood Service Center, East
   2201 East Dominguez Street              829 Lynnhaven Parkway, Suite 130
   Long Beach, California 90801            Virginia Beach, Virginia 23452
   Telephone 1-310-639-5300                Telephone 1-804-340-1702

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BULLETIN # 44
MODEL: TS-120S/TS-180S
SUBJECT: PHONE PATCH TERMINAL ADDITION
                                                            
   Kenwood recommends the PC-1 Phone Patch for all of our radios.
   Most other phone patches will work satisfactorily without any
   modification to the radio, requiring only an external speaker
   connection, and that the Mic line be run through the Patch.
   
   For those operators who desire a Patch input similar to the
   TS-520S or TS-820S, an input connection and terminal must be
   added at the Mic input preamp circuit.
   
   Fixed Divider
   
    Use a 100K in series, with a 10K ohm to ground on the input side
    of the 100K resistor. Use shielded line, and connect as follows:
    
                                        100 K
                                        
                  IN------------100 K ------>
                  GND        |
                             |
                           100 K
                             |
                             |
                            GND   
                                        
    TS-120S
    
    On the IF Gen unit X49-1110-01 install the fixed divider at the
    junction of R43 10K, C42 100pf, &C43 luF (input of Q18). Add
    an RCA jack, or use remote pins 7 and Gnd for input.
    
    TS-180S
    
    On the IF unit X48-1240-00 install the fixed divider at the
    junction of R167 10K, C128 .001uf & C129 luf (input of Q32).
    Add an RCA jack at the predrilled hole on the rear panel for input.