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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 # 957
MODEL: TH-75A
SUBJECT: NO TX ON VHF USING A VEHICLE BATTERY SUPPLY

When the TH-75A is connected to a vehicle battery, ignition or alternator 
noise can be induced on the DC line. When the transceiver is in the 
automatic battery saver mode, the noise pulses overcharge C348 on the RF 
board causing it to short. The supply current opens L218 and the foil 
trace at this coil. To protect the transceiver, a Zener diode will be 
used to clamp the SBR line.

The Zener should be soldered between the SBR side of L218 and the shielding 
case of L221 on the component side of the RF board (X53-3370-11) (A/3). 
The Service Manual disassembly instructions will be required to perform 
this modification.

NOTE: This modification has already been performed on models starting 
      with serial number 007XXXX.

REQUIRED PART: 22V ZENER DIODE - KENWOOD PART # UZP-22B

This is an optional change that is not covered under warranty.
Time to perform this modification is 1 hour or less.