DRAKE TR-4CW - Page 35

DRAKE
5-15. FILTER MATCHING TRANSFORMER.
. Adjust the S meter ZERO pot for zero S meter
deflection (S-1).
_ With the SIDEBAND switch in USB, tune in the
calibrator
signal
at
3.8
MHz
for
maximum
S
meter
reading.
.
Adjust
the
RF
TUNE
control
until
the
S
meter
reads S-9.
Turn the VFO control clockwise to increase the
audio frequency until the S meter drops to S-5.
. Adjust T6 and T13 for maximum S meter reading.
r. Repeat Steps b. through e.
. Center the 9.0 MHz oscillator as described in
paragraph 5-9.
5-16. MIXER AND RF ALIGNMENT.
3
. Tune up the TR—4C at 3.8 MHz for maximum
power output into a dummy load. Set the RF
TUNE control on 5. Adjust the XMTR GAIN
control for 0.2 Amperes plate current as indica-
ted by the plate meter. Adjust T7 bottom and
T9 bottom for maximum plate current.
. Tune up the TR—4C at 7.3 MHz and repeat a.
above, with the RF TUNE control on 6, by
adjusting T8 top and T10 top.
. Set RF TUNE control on 5. Tune up the TR—4C
at 14.3 MHz and repeat a. above by adjusting
T7 top and T9 top.
. Tune up the TR—4C at 29.7 MHz (crystal not
supplied). With the RF TUNE control at 9%
repeat a. above by adjusting T8 bottom and T10
bottom.
. Set RF TUNE control on 5. Tune up the TR—4C
at 21.3 MHz and repeat a. above by adjusting
L6 and L7.
5-17. PANEUTRALIZATION.
. Attach an RF output indicator between the
TR—4C and the dummy load. If no external
output indicator is available. the TR—4C’s own
RF output indicator may be used.
. Tune up the TR—4C on 29.0 MHz for maximum
power output into a dummy load.
. Reduce plate current to 0.2 Amperes with the
XMTR GAIN control.
. While tuning the PLATE control back and forth
through resonance, adjust C76, using an insulated
screwdriver, until the plate current dip and maxi-
mum RF output occur simultaneously. An insula-
ted screwdriver is required because the rotor of
C76 is connected to + 250 Volts DC.
5-18. TRANSMITTER IF NEUTRALIZATION.
a
. With microphone plugged into TR—4C, turn the
VOX gain fully counterclockwise and turn XMTR
GAIN fully clockwise. Place the Mode switch in
the SSB position.
. While talking into the microphone, increase the
RCVR GAIN control setting until speech can be
heard from the speaker.
. Adjust C168 for minimum output from speaker.
. If over one turn of adjustment is required, it will
be necessary to realign T14, C127 and the Carrier
Balance control.
5-19. SMETER ADJUSTMENT.
With the RF GAIN control fully counterclockwise
adjust R187 for an S meter reading of 60 dB over
S-9.
Table 5—3. Tube and Semiconductor Complement
REF Component FUNCTION
DES Type Transmitter Receiver
Vi | 6EA8 Pre-Mixer/Xtal Oscillator | Pre-Mixer/Xtal Oscillator
V2 12AV6 Sidetone Oscillator Diode Det/1st AF Amplifier
V3 6EA8& Cathode Fol. Mixer/Cathode Fol.
v4 6EJ7 Mixer ee
V5 6BZ6 = Crystal Calibrator
V6 12BY7 Driver ——
V7 12BA6 a RF Amplifier