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World of Ham Radio 1997
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asb0815.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 # 815
MODEL: TR-2400
SUBJECT: PULSE NOISE
For elimination of pulse type noise, either in receive, induced by the
LCD oscillator, or in transmit, induced by stray RF in the H.T., install
additional chokes and a capacitor as detailed.
DISASSEMBLY:
1. Disconnect the battery pack and remove from the unit.
2. Remove the 4 case screws, plus two battery pack compartment screws.
3. Seperate the front and rear halves of the radio. DO NOT TEAR WIRES!
4. Unscrew two screws and two threaded retainers holding the PLL unit
X50-1640-10. Slide the unit down to clear the three push switches
from the top panel.
5. Seperate the PLL and RX TX unit. Remove the fish paper insulation from
between the two boards
TX RF NOISE:
1. On the RX TX unit, locate the battery ground (BLACK) lead soldered to
the right edge of the PCB. Desolder this line and install a choke with
ferrite bead L33-0632-05 Resolder along the bottom edge of the board,
as shown.
2. Also on the RX TX unit, locate the YELLOW lead attached to the foil side
of the charge jack J1. Install a .001uF capacitor across J1 to ground
as shown
TX OR RX LCD PULSE NOISE:
1. On the display unit X54-1480-10 locate the YELLOW lead marked B+. Desolder
this lead and install a lJuH choke L40-1021-03 in series. Lead dress MUST
be as shown for physical clearance.
2. Also on the Display unit, adjacent to the B+ lead, desolder the GREEN
E (earth) lead and the BLACK E lead, and wire as shown to another luH
choke, L40-1021-03. Again, observe physical parts placement for clearance.
3. For reassembly, reverse steps 5 through 1. If components were installed
as specified, there will be no clearance problems.