Realistic trc-448 Service Manual Download Page 1 | Manualshive

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Realistic trc-448 Service Manual Download Page 1

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Summary of Contents for trc-448

Page 1: ...40 CHANNEL MOBILE TRANSCEIVER Catalog Number 21 1561 0 00 CUSTOM MANUFACTURED FOR RADIO SHACK A DIVISION OF TANDY CORPORATION REALISTIC...

Page 2: ...BOARD BOTTOM VIEW 19 MAIN P C BOARD TOP VIEW 20 MAIN P C BOARD BOTTOM VIEW 21 WIRING DIAGRAM 1 22 WIRING DIAGRAM 2 23 LED P C BOARD TOP VIEW 24 LED P C BOARD BOTTOM VIEW 24 LED P C BOARD CHANNEL SWITC...

Page 3: ...mA 1000 mA 2000 mA 2500 mA AM SSB 6 dB AM SSB 6 dB AM 0 3 W SSB 2 dB 30 dB 1 dB 0 7 mV 0 7 mV 50 dB 20 dB 0 005 0 005 3 5 4 0 W 10 12 W 10 60 dB 60 dB 40 dB 40 dB 2000 mA 1500 mA 2600 mA 3000 mA AM 1...

Page 4: ...70 dB 50 200 V 50 200 V 65 dB 65 dB 80 dB 80 dB 75 dB 75 dB 10 V 1 0 V 1000 mA 1000 mA 1500 mA 1500 mA 0 6 2 5 kHz 0 6 2 5 kHz 56 dB 56 dB 50 dB 50 dB PUBLIC ADDRESS Microphone Sensitivity Output Powe...

Page 5: ......

Page 6: ...ency is higher than the reference frequency This error voltage appears at Pin 1 The error voltage which appears at Pin 7 and 1 are the result of the phase difference plus effects of harmonics and extr...

Page 7: ...ing it on or off Thus the Transmitter can not operate in an unlocked condition of the PLL The channel selector switch also has an inhibit function when the selector switch is set in between two channe...

Page 8: ...o set a modulation level in the SSB mode IC 3 is a silicon integrated circuit which func tions as a audio amplifier with built in automatic voice operated gain adjustment It is designed to provide an...

Page 9: ...MIX Q225 RF AMP Q223 Q224 IF VV V BLANKER Q228 nn N T213 NOISE AMP IC 201 T214 NOISE DET D236 D237 AMP Q226 Q227 DISASSEMBLY Refer to Figure 1 Step 1 Remove two bracket screwsAO and the Bracket Step 2...

Page 10: ...ALIGNMENT POSITIONS AND POINTS...

Page 11: ...or max output 7 MODE RX USB CH 1 DC VTVM See NOTE 2 below TP 7 TC 3 for 2 5 V DC 0 1 V 8 MODE RX LSB CH 19 Freq Counter with Level Meter TP 3 T3 T4 34 9875 MHz for max output 9 MODE RX LSB CH 1 DC VTV...

Page 12: ...9 3725 34 9775 1 49 149 1 0 0 1 0 1 0 1 19 27 185 34 985 19 3825 34 9875 1 50 150 1 0 0 1 0 1 1 0 20 27 205 35 005 19 4025 35 0075 1 52 152 1 0 0 1 1 0 0 0 21 27 215 35 015 19 4135 35 0175 1 53 153 1...

Page 13: ...or USB CH 19 RF Power Meter 5052 dummy load AF Genarators Monitor Scope 2 AF Generators Freq 500 2400 Hz Output approx 30 mV Set VR 204 to 0 ohm fully counterclockwise VR 4 for 11 W PEP output Fig 5 7...

Page 14: ...r Fig 3 RECEIVER SECTION ALIGNMENT CHART CONTROL SETTING STEP EQUIPMENT TEST EQUIPMENT TEST SETTING ADJUST REFER TO 1 SQ Minimum MODE LSB or USB Sweep Generator Oscilloscope Frequency 7 8 MHz T209 for...

Page 15: ...IGURE 2 Mode Switch Input Test Point Output Test Point Sweep Generator hot ground hot ground AM TP 201 TP 202 TP 205 TP 203 27 MHz USB or LSB TP 206 or TP 214 TP 207 or TP 215 TP 212 TP 213 7 8 MHz TR...

Page 16: ...he carrier level at 10W output power 2 SSB TX VR 3 T 9 Remove AF Generator Minimum carrier level 3 SSB TX TC 7 Minimum carrier level 4 SSB TX Repeat steps 2 and 3 TRANSMITTING SECTION ALIGNMENT SSB Co...

Page 17: ...40MHz Output 10 V T213 T214 Tune T213 and T214 for maximum reading on the DC VTVM Connect Oscilloscope With pulse generator OSCILLOSCOPE T PAD SIGNAL GENERATOR UNIT UNDER TEST PULSE GENERATOR Ant Jac...

Page 18: ...PLL P C BOARD TOP VIEW 11 11111111111111 1 TP 2 TP 3 TP 7 I I TP 4 18...

Page 19: ...PLL P C BOARD BOTTOM VIEW...

Page 20: ...1TP 205 1TP 2031 el k ITP 2061 ITP 2071 TP 215 TP 2111 TP 209 ITP 2011 1TP 214 r 023 1TP 2081 1TP 2161 TP 204 TP 2021 MAIN P C BOARD TOP VIEW...

Page 21: ...P 206 ITP 210I P 213 I FFR T1 3 ITP 2161 TTP 202 1TP 2051 ITP 2031 MAIN P C BOARD BOTTOM VIEW 21...

Page 22: ...WIRING DIAGRAM 1 RFGAINVOL IPASPKRJ EXTSPKR 22...

Page 23: ...WIRING DIAGRAM 2 ORG RED GI 0 L1J CC CI NOISE BLANKER SW I BLU 1 DC 13 8V 23 C237...

Page 24: ...USB LED P C BOARD TOP VIEW BOTTOM VIEW USB BLK LED P C BOARD CHANNEL SWITCH P C BOARD WIRING DIAGRAM ORG RED BRN YEL BLK BRN RED ORG YEL GRN BLU VIO WHT 24...

Page 25: ...t components 3 Wrong frequency in both steps 1 and 2 above Defective IC 2 X4 Q3 Q4 Q6 Q7 Q8 Q13 and or channel selector switch OTHER SECTIONS Symptom Possible Cause 1 Meter lamp does not light and or...

Page 26: ...icrophone PTT switch C Defective MODE Switch 10 Does not transmit AM TX SSB OK A Defective Q236 D228 MODE switch and or associated circuit components 11 Does not transmit SSB TX AM OK RX AM SSB OK A D...

Page 27: ...efective Q214 and or associated circuit components 20 Noise blanker and ANL does not work A Defective IC 201 Q226 Q228 D236 D237 D238 D239 and or associated circuit components B Defective D216 and or...

Page 28: ...nals of 1 28 through 1 72 MHz should read 1 33 through 1 54 MHz 4th line N 128 through 172 should read N 133 through 154 7th paragraph 2nd line Q5 VCO frequency 54 765 to 35 205 should read 34 815 to...

Page 29: ...No 11 12 13 14 15 16 RX AM TX LSB RX LSB I TX AM USB RX USB 1 27 015 34 815 19 2125 34 8175 I 1 33 133 1 0 0 0 0 1 0 1 2 27 025 34 825 19 2225 34 8275 1 34 134 1 0 0 0 0 1 1 0 3 27 035 34 835 I 19 23...

Page 30: ...ol Setting CH 19 should be CH9 Page 17 NOISE BLANKER ALIGNMENT CHART Control Setting CH19 should be CH9 27 115 MHz Page 22 WIRING DIAGRAM Cat a PLL P C Board pattern open at pin 11 of C 2 OPEN Page 24...

Page 31: ...ting trouble shooting first check the PLL section with the channel selector set at CH 15 Page 50 CHASSIS ASSEMBLY PARTS LIST 7 Channel SW MFR s Part Number should be SRH2O2J TAN DY CORPORATION 280 316...

Page 32: ...C HA N N EL SW EXPLODED VIEW NO...

Page 33: ...SCHEMATIC DIAGRAM...

Page 34: ...C2098 D 2SC1634 2SC1364 SC1815 2SC1923 E 3S K45 3S K35 A B A 1 Base 2 Collector 3 Emitter B 1 Gate 2 Source 3 Drain C T 4 1 2 3 C 1 Emitter 2 Collector Heat Sink 3 Base D D 1 Base 2 Collector 3 Emitte...

Page 35: ...SL1626C SCHEMATIC DIAGRAM SL1626C LEAD IDENTIFICATION 55...

Page 36: ...I U S A FORT WORTH TEXAS 76102 CANADA BARRIE ONTARIO L4M 4W5 TANDY CORPORATION AUSTRALIA BELGIUM U K 280 316 VICTORIA ROAD PARC INDUSTRIEL DE NANINNE BILSTON ROAD RYDALMERE N S W 2116 5140 NANINNE WED...

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