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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 # 1056
MODEL: TM-732A
SUBJECT: APC Circuit Improvement

Symptom:

Failures of APC circuit transistor Q232 can occasionally be attributed to 
the gain dispersion characteristics of the VHF power module. Some of these 
devices allow normal transmit power output even with reduced "DB" terminal 
voltages. If the unit is then operated for extended transmit key down
periods Q232 can overheat and fail.

Corrective Action:

1. Measure the transmit power output and the "DB" terminal voltage at a 
dial frequency of 145.020 MHz.

2. Add the 1 dB circuit if the transmitter power is 60 W or greater and 
the "DB" terminal voltage is 10 vdc or less.

3. After adding the attenuator, re-adjust the transmitter output power for 
50 W and check the "DB" voltage. The "DB" voltage should now fall between 
10 and 11 vdc. lf it does not adjust the values for R98, R100, and R99 until 
this voltage range is obtained.

Parts Required:

Description             Part No.        Circuit Description
820 ohm chip resistor	RK73FB2A821J	R98, R100
470 ohm chip resistor	RK73FB2A471J	R98, R100
270 ohm chip resistor	RK73FB2A271J	R98, R 100
5.6 ohm chip resistor	RK73FB2A5R6J	R99
10 ohm chip resistor	RK73FB2A100J	R99
18 ohm chip resistor	RK73FB2A180J	R99

*Note: Quantities vary depending upon level of attenuation required to meet 
requirements of step 3.


Pad Attenuation    R98, R100     R99
1 dB               820 ohms     5.6 ohms
2 dB               470 ohms     10 ohms
3 dB	           270 ohms     18 ohms




        IC-10 <--------R99--------> VHF POWER MODULE INPUT   
                   |         |
                  R98       R100
                   |         |
                   |         |
                  GND       GND

               TX-RX UNIT (X57-4000-02 A/4)


Time required for this modification is 60 minutes or less. 
Service code A:84 B:X57-4000 C:R99 D:91