Alignment Of Transmitter Section; Transmitter Test Equipments Setup - Realistic TRC-449 Service Manual

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
d. R F Power Meter
e. 50 ohm load and Attenuator
2. PROCEDURE (See page 8)
Connect Test Equipment as shown below.
STEP
PRESET TO ADJUSTMENTS
1
S1, S2 : off
VRf5
USB, TX mode
2
Same as step 1 VR16
3
Same as step 2 VR4
VR6: fully CW
CT7: Max. Cap.
L30,L32
4 AF OSC1:
500 Hz
AF OSC2: 2400 Hz
L37,L39
S1 and S2: ON
5 Same as step 4 CT7
6
S1 and S2: OF F
VR8
AM, TX mode
7
S1: ON
VR6
AF
osc:
10000 Hz
8 Same as step 7 VR7
9 Same as step 8 L27
10
S1 and S2 :0FF
VR12
AM, TX mode
h. Tunable Field Strength Meter (Wave meter)
(or Spectrum Analyzer)
I. DC Power Supply (13.8 V/3 amp.)
REMARKS
Break circuit at TP4, place DC mA Meter in series. Adjust for
approximately 40 mA reading. Restore circuit.
Break circuit at TP2, place mA Meter in series. Adjust for ap·
proximate~y
15 mA reading. Restore circuit.
Adjust for minimum carrier leakage for both USB and LSB
on Oscilloscope (or Spectrum Analyzer, if available).
Adjust level of OSC1 and OSC2 for 500 mV reading on AF
VTVM and then adjust coils for max. reading on R F VTVM.
Adjust for 24 volt reading on R F VTVM.
Adjust for 3.8 to 4.0 watt reading on R F Power Meter.
Adjust output of OSC1 for 0.5 mV reading on AF VTVM
then adjust VR6 for 50% modulation on Scope.
Adjust output of OSC1 for 200 mV reading on AF VTVM
then adjust VR7 for 95 to 98% modulation on Scope.
Adjust L27 to show min. 2nd harmonic (54 MHz) on Tunable
Field Strength Meter (or Spectrum Analyzer, if available).
Adjust VR12 so the TRC-449's power meter reads between
red and white area.
TRANSMITTER TEST EQUIPMENTS SETUP
AF
Oscillator
DC
Voltmeter
AF VTVM
1 RC·449
T ranscei ver AN T
-15-
R F Po wer me ter
son
Load
& Attenuator
o
0
000