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World of Ham Radio 1997
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1997-02-01
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==============================================================================
K E N W O O D
>>> A M A T E U R R A D I O S E R V I C E B U L L E T I N <<<
==============================================================================
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
==============================================================================
BULLETIN # 1009
MODEL: TS-950SDX
SUBJECT: 3rd Order IMD Standardization
Symptom:
3rd Order IMD figures have been noted that do not meet our standard value
of -32 to -35 dB.
Cause:
We have found that this symptom can be caused by either improper bias to the
final transistors and/or because of distortion introduced by the 73.05 MHz IF
mixer circuit.
Parts Required:
Qty Description Kenwood Part No. Circuit Designator
3 150 ohm chip resistor RK73FB2A151J R195, R197, R198
1 4.7 Kohm chip resistor RK73FB2A472J R204
2 22 ohm carbon resistor RC05GF2H220J R19, R20
Procedure:
1. On the Final Unit (X45-3450-00) change R19 and R20 from 10 ohms to 22
ohms. (Fig. 1)
2. On the IF Unit (X48-3100-00): (Fig. 2)
a. Change R195 from 56 ohms to 150 ohms
b. Change R197 from 220 ohms to 150 ohms
c. Change R198 from 220 ohms to 150 ohms
d. Change R204 from 10K ohms to 4.7K ohms
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.