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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 # 52
MODEL: TS-520 / BS-5
SUBJECT: BS-5 SWEEP INTERFERENCE
                                                        
   BS-5 users may report ignition-like interference on 80 &40M
   from their SM-220 with BS-5. Noise will be heard between 3850-3870
   Khz, and 7245- 7260 Khz any time the scope is on.
   
   The sweep signal mixes with the IF (carrier) frequency. This
   derived signal, or its second harmonic will usually be less than an
   S1 signal, unless the coax ground to the scope is opened, in which
   case S9 may be indicated.
   
   On the SM-220 PCB X65-1240-00, change the BS-5 +llV DC supply point:
   
         1. Cut the foil path between connector P110 pin 6 &
            Connector P103 pin 2.
             
         2. Install a lS1555 diode between Connector P110 pin 6
            and Connector P103 pin 1.
     
            NEW Part  151555  Vll-0O76-05
      
   Please notate your Service Manuals: SM220, TS-520 & TS-520S