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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 # 1016
MODEL: TS-950S 
SUBJECT: Hum with Monitor ON

Symptom:

On early versions of the TS-950 series a hum might be heard when the MONI
function is active and headphones are connected to the PHONE jack.  No hum is
experienced when the MONI circuit is OFF.

Cause:

This noise can only be found in the monitor circuit itself and not on the
transmitted signal.  We have found that the VCO shield cover for the PLL unit
might be contacting the shield plate for the filter unit.  This physical
contact can allow a slight amount of vibration to be felt in the sub-receiver
section.  This vibration, combined with too much gain in the sub-receiver
section contributes to the hum.
 
Parts Required:

Qty     Description                                    Kenwood Part No. 
4       Low profile PLL Unit cover screws              N35-2640-05     

Procedure:

1. On the IF Unit (X48-3060-00)  adjust VR-1 to the point the audio output 
   just decreases when the MONI circuit is activated.
2. Replace the screws on the VCO Unit shield case with the new low profile 
   screws.

Time required for this modification is 15 minutes or less.
Service code A:09 B:X48-3060 C:VR1 D:91