Carrier Balance; Transmitter Coil - Kenwood TS-900 Operating Manual

Leave the MODE switch at FSK and slide the SG switch to
OFF. Flip the stand-by switch to SEND. Connect a key to
the RTTY jack and close the key. Adjust trimmer TC3 for a
frequency counter reading of 3.396725 MHz. Open the key
and adjust trimmer TC4 for a frequency counter reading of
3.397125. If a frequency shift other than 850 Hz is desired,
use the same procedure to adjust the trimmer for the
desired frequency shift. Be sure to put the stand-by switch
back in the REC position and to turn the SG switch back
on when you are finished.
6.4 OTHER RECEIVER CIRCUITS
To finish aligning the receiver section, make the following
adjustments along the received signal's path.
With the stand-by switch in the REC position, turn the
MODE sWitch to USB. Turn the CAL switch to 25K to turn
on the calibrator. Set the BAND switch to 14 and tune the
VFO to receive the calibrator's signal at 14.175 MHz.
On the IF board (See Figure 22) adjust T1 for a maximum
S-meter reading. Then tune T2 and then T3, each for a
maximum S-meter reading. Adjust the coils in the order
described.
On the NB board (see Figure 20) adjust T6, T7, and T8 as
described in the previous paragraph. Attach a DC voltmeter
to TP5 and tune T4 and then T5 for a minimum voltage
reading,
CAUTION
Never adjust T1, T2, or T3 on the NB board.
On the MIX board (see Figure 24) adjust coil T2 for a
maximum S-meter reading. Turn the calibrator off when
the adjustments are complete.
6.5 TRANSMITTER COIL PACK ALIGNMENT
CAUTION
During transmitter adjustments, connect a 50 ohm
dummy load to the ANT jack. Keep all trans-
mitting periods as short as possible to avoid
damaging the final tubes.
Slide the SG switch (on the rear panel) to the OFF
position, turn the MODE switch to TUN, and set the
METER switch to the ALC position. The DRIVE control
should be in the 12 o'clock position (white line pointed
towards the top of the transceiver).
Adjust the DRIVE coils (See Figure 43) in the same order,
36
and at the same frequencies, shown in Table 6. Set the
BAND switch and VFO to the desired frequency for each
coil. Adjust the coil for a maximum ALC deflection on the
meter. If the ALC reading is too minimal to peak, adjust
the DRIVE control slightly. If the ALC reading is still too
minimal, turn the METER switch to IP, slide the SG switch
to ON, and adjust the coil for maximum IP. Adjust each
coil as described and when finished return the stand-by
switch to REC.
CAUTION
If tuning for maximum plate current, keep the
transmit time as short as possible to prevent
damage to the final tubes.
6.6 CARRIER BALANCE
Use the following method to determine if the balanced
modulator is out of balance.
Tune up the transceiver at 14.175 MHz (in the TUN mode)
with a 50 ohm dummy load attached to the ANT jack. The
SG switch should be in the ON position, the METER switch
should be turned to RF, and the MODE switch should be
placed at USB. Set the stand-by switch to SEND and turn
the RF VOLT control fully clockwise for maximum
sensitivity. If the balanced modulator is out of balance the
RF meter reading will show output. The MIC GAIN control
should be at its minimum setting during this procedure with
no microphone connected.
Rebalance the modulator by adjusting TC1 and VR2 on the
GEN board (See Figure 16) for a minimum RF setting on
the meter.
6.7 TRANSMITTER NEUTRALIZATION
The TS-900 requires neutralization every time any of the
three tubes are changed.
Tune up the TS-900 into adummy load at 21.225 MHz for
CW operation as described in Section 4.9. Set the SG switch
to OFF and place a sensitive RF voltmeter across the
dummy load. Flip the stand-by switch to SEND and adjust
TC1 (see Figure 44) for a minimum reading on the
voltmeter. After the final section is neutralized flip the
stand-by switch to REC.
Slide the SG switch to ON and turn the driver's screen grid
switch off. The switch is in the RF section, on the same
board as the 6GK6 tube (See Figure 45). Switch the
stand-by switch to SEND and adjust TC2 (driver board) for