Realistic TRC-410 Service Manual page 8

0
RF Power Meter Dummy Load
RF Power Meter
Spectrum Analyzer
63dB
00
RF ATT
b
(-40 dB)
SET
Antenna
Jack
DC
Power Supply 2nd Harmonic
Fundamental
Figure 9
SET
Antenna
Jack
DC
Power Supply
da
o
10
Figure 8
Coupler
Field Strength
Meter
000OO
2. General Alignment Conditions
1. Signal input must be kept as low as possible, to avoid overload and
clipping. (Use highest possible sensitivity of output indicator.)
2. Standard modulation is 1000 Hz at 30% amplitude.
3. A non-metallic alignment tool must be used for all adjustments.
4. Power supply adjusted for 13.8 V DC, 2A.
NOTE: Figure 1 provides alignment location information.
3. Alignment Procedure
STEP
SIGNAL SOURCE
CONNECTION
OUTPUT INDICATOR
CONNECTION
SET SIGNAL
ADJUST ADJUST FOR
1 Set Channel Selector to Channel 18.
2 Turn VR-2 (SQUELCH) fully counterclockwise.
3
Turn VR-4 (VOLUME) fully clockwise.
4
Connect RF Signal
Generator (455 kHz,
30%) to base
of Q4 through 0.01 p F
Capacitor.
Connect V.T.V.M.
across EXT. Speaker
Jack with 8 Q Dummy
load. (Figure 10)
455 kHz, 1 kHz 30%
Modulation. Adjust the
output of RF Signal
Generator to a minimum
level, so the IF circuit
is not saturated.
T4 Alignment of
2nd IF
Adjust for maximum
output.
T5
5
6 Connect RF
Signal
Generator to
Antenna
Connector.
Connect V.T.V.M. and
Distortion Meter across
Ext. Speaker Jack with
8 Q Dummy load.
(Figure 11)
27.175 MHz
1 kHz, 30%
Mod.
T1 Overall Adjustment
Adjust for maximum
indication on V.T.V.M.
Reduce output from
RF SG so that audio
output remains about
500 mW (2 V).
T2
7
T3
8
T4
9
10
Repeat steps 6 through 9 as necessary to obtain maximum output.
11
Same as
step 6
Same as
step 6.
27.175 MHz 1 kHz,
80% Mod. Set
Output of RF SG to
1 mV.
T5 Alignment of T5
Adjust for minimum
indication on Distortion
Meter.
12
Same as
step 6
Same as
step 6.
27.175 MHz 1 kHz, 30%
Mod. Set output of RF
SG to 0.316
pV.
R21 Adjustment of IF Gain
Confirm 2V indication
on V.T.V.M.
If not 2V, change value
of R21 (330-1K)
13
Same as
step 6
Same as
step 6.
27.175 MHz 1 kHz,
30% Mod. Set Output
of RF SG to 1 mV.
VR3
Adjustment of
SQUELCH
Turn VR-2 (SQUELCH)
fully clockwise. Adjust
output "on".
14
Same as
step 6
Same as
step 6.
27.175 MHz 1 kHz,
30% Mod. Set Output
of RF SG to 50
pV.
VR4 Adjustment of LED
S-Meter
Adjust so fourth LED
on S/RF Meter lights.
C. RECEIVER SECTION
1. Test Equipment Required
a. RF Signal Generator
b. V.T.V.M.
c. Distortion Meter