Realistic trc-449 Service Manual page 15

ALIGNMENT OF TRANSMITTER SECTION
1. Equipment Required:
a.
AF Oscillator (two required)
f. Oscilloscope
b.
AF VTVM (Full scale: 1V DC with RF probe) g. RF VTVM
c.
DC VOM
h. Tunable Field Strength Meter (Wave meter)
d.
RF Power Meter
(or Spectrum Analyzer)
e. 50 ohm load and Attenuator
I. DC Power Supply (13.8 V/3 amp.)
2. PROCEDURE (See page 8)
Connect Test Equipment as shown below.
STEP
PRESET TO ADJUSTMENTS
REMARKS
1
51, S2: off
USB, TX mode
VR15
Break circuit at TP4, place DC mA Meter in series. Adjust for
approximately 40 mA reading. Restore circuit.
t
Same as step 1 VR16
Break circuit at TP2, place mA Meter in series. Adjust for ap-
proximately 15 mA reading. Restore circuit.
3
Same as step 2
VR4
Adjust for minimum carrier leakage for both USB and LSB
on Oscilloscope (or Spectrum Analyzer, if available).
4
VR6: fully CW
CT7: Max. Cap.
AF OSC1:
500 Hz
AF OSC2: 2400 Hz
S1 and S2: ON
L30, L32
L37,L39
Adjust level of OSC1 and OSC2 for 500 mV reading on AF
VTVM and then adjust coils for max. reading on RF VTVM.
5 Same as step 4
CT7
Adjust for 24 volt reading on RF VTVM.
6
Si and S2: OFF
AM, TX mode
VR8
Adjust for 3.8 to 4.0 watt reading on RF Power Meter.
7
51: ON
AF OSC: 10000 Hz
VR6
Adjust output of OSC1 for 0.5 mV reading on AF VTVM
then adjust VR6 for 50% modulation on Scope.
8
Same as step 7 VR7
Adjust output of OSC1 for 200 mV reading on AF VTVM
then adjust VR7 for 95 to 98% modulation on Scope.
9 Same as step 8
L27
Adjust L27 to show min. 2nd harmonic (54 MHz) on Tunable
Field Strength Meter (or Spectrum Analyzer, if available).
10
51 and S2:OFF
AM, TX mode
VR12
Adjust VR12 so the TRC-449's power meter reads between
red and white area.
TRANSMITTER TEST EQUIPMENTS SETUP