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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 # 1042
MODEL: TM-642A/TM-742A/TM-942A
SUBJECT: Microprocessor Change 

This bulletin supercedes ASB-1033.

Symptom:

Reports of problems with microprocessor lock-up when using S-meter squelch, 
problems with storage/recall of PL tone frequencies of 203.5 Hz. and/or 
114.8 Hz., or problems with a lack of transmit on the UHF band modules during
Remote operation can be corrected using the changes noted in this bulletin.

Notes:

1. All TM-642A transceivers work fine and do not require any changes.

2. TM-742/942's that exhibit any of these symptoms with serial numbers between
   412XXXX and 509XXXX need only change IC1 on X53-3460-21 B/2.

3. TM-742/942's that exhibit any of these symptoms with serial numbers of 
   412XXXX and below must also change IC1 on X54-3130-11.

4. TM-742's with serial numbers of 509XXXX and greater have had these changes
   incorporated in production.

5. Some TM-742's and TM-942's below serial number 509XXXX were returned 
   to Japan for modification. If the unit that you have has a black dot on 
   the box near the serial number it has already been modified and requires 
   no further action

Parts Required:

Qty    Description    Old Part No.     New Part No.       Circuit Description

1      Microprocessor HD6433388A07F    HD6433388A22F      IC-1
                           or
                      HD6433388A14F                         

1      Microprocessor HD404719A26H     HD404719A32H       IC-1

Caution: This modification requires advanced surface mount soldering 
equipment that is rated for CMOS circuits. It also requires familiarity 
with advanced surface mount soldering techniques. If you do not have the 
proper equipment or knowledge do not attempt this modification yourself. 
Attemping to remove and replace either IC without the proper equipment and
techniques can easiy damage the circuit boards and void your warranty. 
Seek qualified assistance from your closest Kenwood Service Center 
(Long Beach, CA, or Virginia Beach, VA).

Time required for this moditication is 90 minutes or less. 
Service code A:98 B:X53-346 B/2 C:IC1 D:91