Realistic TRC-410 Service Manual
Service
CB 40-CHANNEL TRANSCEIVER
TRC-410
Catalog Number • 21-1504
CUSTOM MANUFACTURED FOR RADIO SHACK MA DIVISION OF TANDY CORPORATION
CONTENTS
1.
SPECIFICATIONS
3 - 4
2.
BLOCK DIAGRAM
5
3.
ALIGNMENT INSTRUCTIONS
6 - 9
4.
FREQUENCIES GENERATED AND MIXED TO OBTAIN EACH CHANNEL
9
5.
TRANSISTOR LEAD IDENTIFICATION AND IC INTERNAL CONNECTION .. 10 - 11
6.
TROUBLESHOOTING
12
7.
TRANSISTOR AND IC VOLTAGE CHART
13
8.
PRINTED CIRCUIT BOARD (TOP VIEW)
14 - 15
9.
PRINTED CIRCUIT BOARD (BOTTOM VIEW)
16 - 17
10.
ELECTRICAL PARTS LIST
18 - 21
11.
EXPLODED VIEW PARTS LIST
21
12.
SCHEMATIC DIAGRAM
22 - 23
13.
EXPLODED VIEW/DISASSEMBLY INSTRUCTIONS
24 - 25
1. SPECIFICATIONS
GENERAL SPECIFICATIONS
Description
Transmitter
Crystal controlled PLL synthesizer, amplitude modulation
Receiver
Crystal controlled double conversion, superheterodyne system
Communicating frequencies
All 40 CB channels (26.965 to 27.405 MHz)
Voltage operation
12 — 16 V DC
(positive or negative ground vehicles)
Temperature and Humidity range
—30
°
C to + 60
°
C and 10% to 90%
Electronic
STANDARD TEST CONDITIONS
Battery supply voltage
13.8 V DC
Modulation
1000 Hz, 30%
Receiver "outputpower
500 mW at external SP.
Receiver output impedance
8 ohms, non-inductive
Ant. load impedance of transmitter
50 ohms, non-inductive
Ambient conditions
temperature
17 to 23°C
humidity
40 to 70%
TRANSMITTER SPECIFICATIONS
Description
Nominal
Limit
RF power output
. 4.0 watts (max.) . . . .... 3.6-4.4 watts
Emission
8A3
Modulation capabilities
+90%, —95%
AMC Range at 1 kHz
40 dB
> 30dB
Frequency accuracy
0 002% . .... . . . . . ...
0.005%
Transmitter/Receiver switching
Spurious radiation & Harmonic
signal radiation ratio from fundamental
Current consumption
unmodulated
80% modulated
Envelope distortion
Hum and Noise level
Stability against variation of
antenna impedance
1050 mA
1400 mA
1600 mA
1950 mA
10% max. 1000 Hz, 50% mod.
40 dB min. below max. mod.
Satisfactory when dummy antenna
is varied from 40 ohms to 200 ohms.
—65 dB
—60 dB
RECEIVER SPECIFICATIONS
Description
Nominal
Limit
Intermediate frequency
1st IF
10.695 MHz
2nd IF
455 kHz
Sensitivity for 500 mW output
0.25 ,uV
0.5 ,uV
Sensitivity at 10 dB S + N/N
0.6 ,uV
1.2 AN
Adjacent channel rejection
60 dB
56 dB
Image rejection (1st IF/2nd IF)
45 dB
35 dB
IF rejection ratio (1st IF/2nd IF)
70 dB
60 dB
Signal-to-Noise ratio
at 1 mV input
40 dB
34 dB
Distortion at 1 mV input,
50% mod. (500 mW out)
3%
6%
AGC Figure of merit at 50 mV input
90 dB
70 dB
Power output at 500 ,uV Input
Undistorted (10% THD)
3.5 W
3.0 W
Maximum
6.0 W
4.0 W
Electrical fidelity compared to 1000 Hz
450 Hz
—5 dB
—6+3 dB
2500 Hz
—5 dB
—6+3 dB
Cross modulation
50 dB
45 dB
Squelch
Adjustable from 0.6 AN to 1 mV
Current consumption (no signal)
190 mA
280 mA
"S" meter sensitivity to light 4th LED
10 ,uV
5 — 20 pV
OTHER ITEMS
Fuse
2 Amp.
General power requirement
12 — 16 V DC
Dimensions
(H) 1-18/32"(40mm) x (W) 4-30/32"(125mm) x (D) 8-5/32"(207mm)
Weight
2 lb 2 oz. (1 kg)
NOTE: Nominal Specs represent the design specs; all units should be able to approximate these
— some will exceed and some may drop slightly below these specs. Limit specs represent the
absolute worst condition which still might be considered acceptable; in no case should a unit
perform to less than within any Limit spec.
4
2. BLOCK DIAGRAM
Q15
Base of
oo
Output of CF3
Base of 04 1
Frequency Counter
output of CF-3
Figure 2
R7I / R 72
DC VOLT METER
I
Figure 3
Base of QI5
RF V.T.V.M.
3. ALIGNMENT INSTRUCTIONS
Bose of 017
A. PLL SECTION
1. Test Equipment Required
a.
Frequency Counter
b.
DC Power Supply (13.8 Volt, 2.5 Amp.)
c.
DC Volt Meter (above 100 KQ/V)
T8
TI I
©I
=,3 fiR72
1-10
J
3R71
CF3
C75
T5
R2I
04
T3
T
T4
VR4
D VR5
017
5
015 L5
O
L4
ANT. JACK
EXT .SP. JACK
NOTE: Figure 1 provides test point and
alignment location information.
2. Alignment Procedure
CHANNEL
SQUELCH
VR 2
VOLUME
VR I
Figure 1
TI
al
STEP
OUTPUT INDICATOR
CONNECTION
ADJUST
ADJUST FOR
1
MIC: Receive, POWER: "on", VOLUME: Optional, SQUELCH: Optional, Channel Selector: Optional.
2
Connect Frequency Counter to output
of CF-3 (Figure 2).
C75
If the frequency is not 10.240 MHz ± 400 Hz,
change value of C75 (18-39 pF).
3
MIC: Transmit, Channel Selector: Channel 40.
4
Connect DC Volt Meter to R71/R72
(Figure 3).
T8
Alignment of VCO
Adjust for 6.0 Volt indication on DC
Volt Meter.
5
MIC: Receive, Channel Selector: Channel 1.
6
Same as step 5.
Check for indication on DC Volt Meter; must be 2.5-3.5 Volt.
If DC Volt Meter does not indicate 2.5-3.5 Volt, readjust T8
(return to step 4).
B. TRANSMITTER SECTION
1. Test Equipment Required
a.
RF Output Power Meter
b.
50 Ohm Load (non-inductive)
c.
RF Attenuator
d.
Oscilloscope
e.
Audio Generator
f.
DC Power Supply (13.8 Volt, 2.5 Amp.)
g.
Field Strength Meter (or Spectrum Analyzer)
h.
Frequency Counter
i.
Coupler
NOTE: Figure 1 provides test point and alignment location information.
2. Alignment Procedure
Figure 4
STEP
SIGNAL SOURCE
CONNECTION
OUTPUT INDICATOR
CONNECTION
ADJUST
ADJUST FOR
1
Set Channel Selector to Channel 18.
2
Disconnect R95 (or short base of Q17 to ground with 0.01 ,u F).
3
Connect RF V.T.V.M. to base
of Q15 (Figure 4).
T10
Alignment of
Pre-driver Stage
4
T11
Adjust for maximum
indication on RF V.T.V.M.
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