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World of Ham Radio 1997
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WOHR97_AmSoft_(1997-02-01).iso
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asb1026.txt
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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 # 1026
MODEL: TS-950SDX
SUBJECT: "Click Noise" with NOTCH ON
Symptom:
A click noise might be generated when receiving a strong signal (S-9 or above)
when the NOTCH is ON and the Notch Control is turned away from the notch point.
Corrective Action:
Lengthening the AGC release time of the IF Amp just before the NOTCH circuit
will correct this symptom. The enclosed modification has been designed to
change the time constant only when the NOTCH circuit is activated. Do not
install this modification on sets that do not exhibit this symptom as the AGC
FAST time constant is affected by this change.
1. Cut the printed circuit foil pattern between the test point (TP) and
gate 2 of Q2 as shown.
2. Install the 47 K ohm chip resistor from TP to gate 2 of Q2.
3. Add a 0.047 uF ceramic capacitor as shown in the accompanying
illustration.
4. Add the DTC124ES transistor as shown.
Note: The .047 uF capacitor and the digital transistor must be connected
together as shown and installed so that they do not touch the
surrounding circuit board patterns.
5. Install a jumper wire from the base of the digital transistor to pin
number 6 of CN14.
Parts Required:
Qty Description Kenwood Part No. Circuit Description
1 0.047 uF capacitor CK45B1H473Z NA
1 Digital Transistor DTC124ES NA
1 47K Chip resistor RK73FB2A473J NA
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 1 hour or less.
Service code A:09 B:X57-4130-00 C:ADDTR D:91