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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 # 1025
MODEL: AT-50
SUBJECT: Blows ACCY Fuse in TS-50S 

(Supercedes ASB-1010)

Symptom:

Attempting to tune the AT-50 when it is connected to an antenna with a
relatively high SWR value, especially on the 3.5 MHz band might cause the 
ACCY fuse to open in the TS-50S.     

Parts Required:
Qty     Description             Kenwood Part No.         Circuit Designation 

2       Toroidal coil           L33-0699-05               None
                
Procedure:

1. Remove the top and bottom covers from the antenna tuner.
2. Locate X53-3470-00 D/4 (It is attached to the top left side of the
   chassis with the foil side up.)
3. Remove the two .047 uF capacitors shown in figure 1 if they are present.
4. Cut the foil and add one of the toroidal inductors as shown in figure 2.
5. Turn the tuner over and locate capacitor C123 and C124, as shown in
   figure 3.
6. Move the capacitors (or add new capacitors) to the locations shown in
   figure 3.
7. Cut the foil path and add the remaining toroidal inductor as shown in
   figure 3.
8. Remove Jumper W106 as shown in figure 3. (Note remove the jumper from
   the component side of the board.)
9. Add a jumper from the ATG foil to W104 as shown in figure 3. 
10.Replace the top and bottom covers.

No additional adjustments or modifications will be required.

Caution:   This modification requires soldering equipment rated for CMOS type
circuits.  It also requires familiarity with surface mount soldering
techniques.  If you do not have the proper equipment or knowledge do not
attempt this modification yourself.  Seek qualified assistance.

Time required for this modification is 30 minutes or less.
Service code A:48 B:X53-3470-00 C:ADDL D:91