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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 # 866
MODEL: TS-930S
SUBJECT: Hetrodyne Tone

Some users of the TS-930S have reported that a heterodyne is heard when 
the VBT control is tuned in the CW mode. The tone may be more noticeable 
with no signal presentt (e.g. no antenna connected.), or when the AF 
tune or CW PITCH controls are tuned. This may be reduced or eliminated 
by the following procedures. 

PARTS REQUIRED

	QTY	DESCRIPTION	KENWOOD PART NUMBER

          1     Shield Kit                   Z930CARSHIELD
          1     Cover CAR                    F11-0813-04
          1     Shield CAP                   F10-1380-04 
          1     8.2K 1/4 watt Resistor
          1     22K  1/4 Watt Resistor
          1     3pf disc capacitor
          1     0.5pf disc capacitor
          1     1.0pf disc capacitor

PROCEDURE

1. Remove the top and bottom covers from the TS-930S. 
2. Turn the radio bottom up to allow access to the Signal Unit (X57-1000-11). 
3. Remove the twenty-two (22) screws that secure the Signal Unit/Heat 
   sink to the chassis. Unplug the RAT, DRV, XVT, FRO, and the VCOF 
   coaxial cables from the Signal Unit. These are located along the rear 
   and the left side of the Signal Unit. Unplug connectors number (16) 
   and (20) located along the right of the Signal Unit. 
4. Gently lift up on the rear of the Signal Unit and fold the board over 
   towards the front panel to allow access to the bottom of the board. 
5. Install the shield plate on the botton of the board. Cut the circuit 
   foil and add the jumper wire as shown. 
6. Change the following components:

Change R635 to 8.2K 
Change R501 to 22K 
Change C469 to 3pf 
Change C473 to .5pf 
Change C476 to 1pf 

7. Reinstall the signal unit. Pay carefull attention to the coaxial 
   connectors when reinstalling to ensure they are in the correct locations. 

8. Install the top cover to CAR 1 enclosure to complete the Signal Unit 
   modification.

9. Turn the set over so top is up. Remove the four (4) screws that secure 
   the speaker assembly to the chassis and lift up gently (unplug the 
   battery backup connector). The assembly may then be folded over to 
   the right with cables attached. Remove the four (4) screws that secure 
   the Digital assembly to the chassis and fold the assembly up and 
   towards the front panel, to allow access to the PLL Unit. 

10. Remove resistor R73 and capacitor C99 from the PLL Unit. 

11. Reverse the procedure in step 9 to reinstall the Digital and Speaker Units.

ADJUSTMENTS

1. Connect an oscilloscope probe to the CAR 1 terminal (24) of the Signal Unit.
   Adjust L161 for 300mv p-p signal amplitude. 

2. Connect the oscilloscope probe to the emitter of Q79. Adjust L142, L144, 
   and L145 for maximum signal amplitude, then adjust L139 for lv p-p 
   amplitude. 

          *NOTE: NOTE THE USB FREQUENCY BEFORE ADJUSTING L139. 

3. Adjust TC4, TC5, and TC6. (Refer to Service Manual) 

4. Adjust TC3 so the frequency is again the same as measured in Step 2. 

4. Replace top and bottom covers to complete the modification.

	Time required for this modification is 1 hour.