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World of Ham Radio 1997
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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 # 849
MODEL: TR-9000
SUBJECT: Transmitter Sideband Carrier Balance
Distorted sideband transmission may have one of two causes.
If normal alignment does not cure the problem, distortion
or poor carrier suppression may be improved by rerouting two
leads in the wire harness
PERFORM THESE INITIAL CHECKS FIRST:
1. On early units, ascertain that R74, 47 ohm is present on the
TX unit X56-1370-10 between connector 33, the LT line,
and R27, 2.2K (vicinity of Q5, Q6), and that R27 is 2.2K.
(Service Bulletin #824).
2. Verify TR-9000 Service Manual alignments, General section
steps 4 (PLL), and 5 (HET frequency alignment).
3. TX section, steps #4 (power adjustment), 9 (SSB mic gain),
10 (carrier point) & 11 (carrier suppression).
PROCEDURE:
1. Remove the bottom cover and unplug the speaker.
2. With the radio upside down and facing forward, locate
connectors 8 and 10 at the front of the RX unit X55-1260-00.
Connector # 8, pin 3 (violet) is the -6V DC line from the
TX unit, connector # 31, pin 1. Connector # 10, pins 7
(signal) and 8 (ground) (green coaxial cable) is the MS
pins 5 (sig) and 4 (gnd).
3. Carefully cut the cable ties (without cutting any leads)
securing these two lines in the wire harness which runs
to the left, around the upright Control unit, and then
right behind the front panel as far as the Mode switch.
4. Carefully unplug each of these connectors by gripping
the connector housing with a long-nosed plier.
5. Extract the terminal from the housing by depressing the
locking tab and simultaneously withdrawing the lead with
terminal. (see illustration on page 2).
6. Reroute these two lines from the behind the Mode switch,
between the chassis and control unit, then left to their
original connectors. Reinstall the terminals in their
original positions in the connector housing.
7. Coil the excess of each lead and secure with cable ties.
Retie the harness behind the front panel, along the left
of the chassis, and back behind the control unit.
8. Readjust carrier suppression. Mod SW:USB, Mic terminal
terminated with 470 ohm. On the RX unit, alternately adjust
TC1 & VR6 for minimum output at 145MHz. Carrier should
be at least -4OdB down.
9. Work is complete. Replace the bottom cover.