dr620_SM.pdf

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1、DR-620 Service Manual CONTENTS SPECIFICATIONS 1) GENERAL . 2 2) TRANSMITTER . 2 3) RECEIVER . 3 CIRCUIT DESCRIPTION 1) VHF Reception . 4 2) UHF Reception . 5 3) FM Reception . 5 4) V/V (VHF-VHF) Dual Reception. 6 5) U/U (UHF-UHF) Dual Reception . 6 6) VHF Squelch Control . 6 7) UHF Squelch Control.

2、6 8) Transmit Signal Path . 7 9) VHF Transmit Signal Path . 7 10) UHF Transmit Signal Path . 7 11) VHF Tx APC Circuit . 7 12) UHF Tx APC Circuit . 8 13) VHF PTT Circuit. 8 14) UHF PTT Circuit . 8 15) VHF PLL. 8 16) UHF PLL. 9 17) Power-on Circuit . 9 SEMICONDUCTOR DATA 1) M5218FP (XA0068) . 10 2) NJ

3、M78L05UA (XA0098) . 10 3) NJM7808FA (XA0102) . 10 4) TC4S66F (XA0115) . 11 5) AN8010M (XA0119). 11 6) BU4052BF (XA0236) . 11 7) TA75S01F (XA0332) . 12 8) TC4W53FU (XA0348). 12 9) TA31136FN (XA0404). 12 10) LA4425A (XA0410). 13 11) NJM2904V (XA0573). 13 12) NJM2902V-TE1 (XA0596) . 13 13) S-80845ALMP-

4、EA9-T2 (XA0620) . 14 14) TK10931V (XA0666). 14 15) BR24C64F-E2 (XA0669) . 15 16) LC75884W (XA0899) . 16 17) M51132FP (XA0900) . 17 18) M30620FCAGP (XA0913/XA0949) . 1719 19) M38503M2H667FP (XA0914). 2021 20) M64076AGP (XA0915) . 22 21) S-816A50AMC (XA0925). 23 22) NJM78M05DL1A (XA0947) . 23 23) Tran

5、sistor, Diode, and LED Outline Drawings. 2425 24) LCD Connection . 2627 EXPLODED VIEW 1) Front View. 28 2) Bottom View. 29 PARTS LIST Front Unit . 3031 LED Unit . 31 Main Unit . 3142 Mechanical Parts . 42 Packing Parts. 42 Accessories (Screw Set). 42 ADJUSTMENT 1) Adjustment Spot . 43 2) Adjustment

6、Mode. 44 3) VHF Adjustment Specification. 45 4) UHF Adjustment Specification . 46 5) VHF Test Specification . 47 6) UHF Test Specification. 48 PC BOARD VIEW 1) Front Side A. 49 2) Front Side B. 49 3) Main Side A . 50 4) Main Side B . 51 FRONT SCHEMATIC DIAGRAM. 52 MAIN SCHEMATIC DIAGRAM. 53 FRONT BL

7、OCK DIAGRAM. 54 MAIN BLOCK DIAGRAM. 55 ALINCO,INC. 2 SPECIFICATIONS 1) GENERAL Frequency coverage87.500 - 107.995MHz (WFM RX) DR-620T (U.S amateur)108.000 - 135.995MHz (AM RX) 136.000 - 173.995MHz (RX) 144.000 - 147.995MHz (TX) 335.000 - 479.995MHz (RX) 430.000 - 449.995MHz (TX) DR-620E (European am

8、ateur)87.500 - 107.995MHz (WFM) 144.000 - 145.995MHz (RX, TX) 430.000 - 439.995MHz (RX, TX) Operating mode16K0F3E (Wide mode) 8K50F3E (Narrow mode) Frequency resolution5, 8.33, 10, 12.5, 15, 20, 25, 30, 50, 100kHz Number of memory channels200 Antenna impedance50 unbalanced Power requirement13.8V DC1

9、5% (11.7 to 15.8V) Ground methodNegative ground Current drainReceive0.6A (Max.)0.4A (Squelched) Transmit11.0A Operating temperature- 10 to 60 C Frequency stability2.5ppm Dimensions142 (w) 40 (h) 174 (d) mm (w/o knobs) WeightApprox. 1.0kg 2) TRANSMITTER Output powerHigh : 50W (VHF) 35 W(UHF) Mid : 10

10、W Low : 5W Modulation systemVariable reactance frequency modulation Maximum frequency deviation5kHz (Wide mode) 2.5kHz (Narrow mode) Spurious emission-60dB Adjacent channel power-60dB Modulation DistortionLass than 3% Microphone impedance2k 3 3) RECEIVER Sensitivity-16dBu for 12dB SINAD Receiver cir

11、cuitryDouble conversion superheterodyne Intermediate frequency1st 21.7MHz 2nd 450kHz (VHF) 1st 45.1MHz 2nd 455kHz (UHF) Squelch sensitivity-18dBu Selectivity (-6dB / -60dB)12kHz / 24kHz Spurious and image rejection ratio70dB Audio output power2.0W (8, 10% THD) ! Note : All specifications are subject

12、 to change without notice or obligation. 4 CIRCUIT DESCRIPTION 1) VHF Reception Incoming VHF signals are passed through a low-pass filter network, antenna switching diodes D20 (1SV268), D19 (1SS355) and D26 (DAN235E), and a high-pass filer network, and on to the RF amplifier Q19 (3SK131). The amplif

13、ied RF signal is passed through another RF amplifier Q18 (2SC5226) and band-pass filtered again by varactor-turned resonators L46, L49, L51 and D28, D29, D30 (all HVU359), then applied to the 1st mixer Q21 (3SK240) along with the first local signal from the PLL circuit. The first local signal is gen

14、erated between 122.3 MHz and 126.3 MHz by the VHF VCO, which consists of Q9 (2SK508) and varactor diodes D10, and D11 (both 1SV282) according to the receiving frequency. The 21.7 MHz first IF signal is applied to monolithic crystal filters XF and XF2 (both Q2175AD20) which strip away unwanted mixer

15、products, and the IF signal is applied to the first IF amplifier Q20 (2SC4618). The amplified first IF signal is then delivered to the FM IF subsystem IC IC3 (TK10931V), which contains the second mixer, limiter amplifier, noise amplifier, and FM detector. The second local signal is generated by 21.2

16、5MHz TCXO, producing the 450 kHz second IF signal when mixed with the first IF signal within IC3. The 450 kHz second IF signal is applied to the ceramic filter FL1 (ALFYM450E) which strips away all but the desired signal, and then passes through the limiter amplifier within IC3 to the discriminator

17、coil L101, which removes any amplitude variations in the 450 kHz IF signal before detection of speech. The detected audio then signal is amplified by IC9 (NJM2902V-B) passes through the de-emphasis network, a high-pass filter consisting of IC9 (NJM2902V-A) and associated circuitry, and low-pass filt

18、er consisting and associated circuitry. The filtered audio signal is switched by IC12 (BU4052), then passes through the audio volume control IC IC13 (M511312FP) which adjusts the audio sensitivity to compensate for audio level variations. The audio signal is amplified by IC8 (LA4425A), then applied

19、to the internal loudspeaker. 5 2) UHF Reception Incoming UHF signals are passed through a low-pass filter network, high-pass filter network, antenna switching diodes D16 (1SS355) and D18 (1SV268), and on to the band-pass filter network consisting of varctor diode D49 (HVU359) and L79. The filtered U

20、HF signal is amplified by RF amplifier Q41 (3SK240) and fed to another band-pass filter consisting of varactor diode D50 (HVU359) and L80, and then is passed through another RF amplifier Q43 (2SC5226) to another band-pass filter consisting of varactor diodes D51 and D52 (both HVU359) and L81/L82. Th

21、e amplified and filtered UHF signal is applied to the 1st mixer Q42 (3SK240) along with the first local signal from the PLL circuit. The first local signal is generated between 384.9 MHz and 404.9 (*2) MHz by the UHF VCO, which consists of Q29 (2SK508) and varactor diodes D38 and D40 (both ISV278),

22、according to the receiving frequency. The 45.1MHz first IF signal is applied to monolithic crystal filters XF3A and XF3B (Q4511BD10) which strip away unwanted mixer products, and the IF signal is applied to the first IF amplifier Q44 (2SC4618). The amplified first IF signal is then delivered to the

23、FM IF subsystem IC IC5 (TA31136FN), which 2) The amplified first IF signal is then delivered to the FM IF subsystem IC IC5 (TA31136FN), which contains the second mixer, limiter amplifier, noise amplifier, and FM detector. The second local signal is generated by 45.555 MHz crystal X4, producing the 4

24、55 kHz second IF signal within IC5. The 455kHz second IF signal is applied to the ceramic filter FL4 (CFW455E) which strips away all but the desired signal, and then passes through the limiter amplifier within IC5 to the discriminator coil L102 , which removes any amplitude variations in the 455 kHz

25、 IF signal before detection of speech. The detected audio then signal is amplified by IC9 (NJM2902V-C) passes through the de-emphasis network, a high-pass filter consisting of IC9 (NJM2902V-D) and associated circuitry, and a low-pass filter consisting and associated circuitry. The filtered audio sig

26、nal is switched by IC12 (BU4052), then passes through the audio volume control IC IC13 (M511312FP), which adjusts the audio sensitivity to compensate for audio level variations. The audio signal is amplified by IC8 (LA4425A) then applied to the internal loudspeaker. 3) FM Reception Incoming FM signa

27、ls are passed through a low-pass filter network, antenna switching diodes D19 (1SS355), D20 (1SV2685) and D26 (DAN235E), and a high-pass filter network, and on the RF amplifier Q36 (2SC5066). The amplified RF signal is passed through band-pass filtered L, C, then applied to the 1st mixer Q33 (2SC506

28、6) along with the first local signal from the circuit. The first local signal is generated between 86.7 MH and 118.7 MHz by the FM VCO, which consists of Q14 (2SC4808) and varactor diodes D23, and D25, (both 1SV282) according to the receiving frequency. The 10.7 MHz first IF signal is applied to cer

29、amic filters FL3 (SFT10.7MAS) which strip away unwanted mixer products, and the IF signal is applied to the first IF amplifier Q37 (2SC4618). The amplified first IF signal is then delivered to the FM IF subsystem IC IC3 (TK10931V), limiter amplifier, noise amplifier, and FM detector. The 10.7 MHz fi

30、rst IF signal is applied to the discriminator coil L53, which removes any amplitude variations in the 10.7 MHz IF signal before detection of speech. 6 4) V/V (VHF-VHF) Dual Reception During V & V operation, the incoming VHF “sub” band signal is passed through a low-pass filter network, antenna switc

31、hing diode D19 (1SS355), D20 (1SV268) and a high-pass filter network to the RF amplifier Q19 (3SK131). The amplified RF signal is passed through a high-pass filter network, VHF “sub” RF amplifier Q31 (2SC5066), and a low-pass filter network, then is applied to the VHF “sub” first mixer Q32 (2SC5066)

32、 along with the 45.1 MHz VHF “sub” first local signal from the VHF “sub” VCO circuit. The VHF “sub” first local signal is generated between 189.1 MHz and 193.1 MHz by the VHF “sub” VCO Q38. The 45.1 MHz VHF “sub” second IF signal is applied to the UHF receiving circuit. The VHF “sub” signal is ampli

33、fied, filtered, and demodulated, etc., by the UHF “main” receiving circuit, described previously. 5) U/U (UHF-UHF) Dual Reception During U/U operation, the incoming UHF “sub” band signal is passed through high-pass and low-pass filter networks, antenna switching diodes D16 (1SS355) and D18 (ISV268),

34、 and another high-pass filter network to the RF amplifier Q51 (2SC5066). The amplified RF signal is passed through a low- pass filter network, UHF “sub ”RF amplifier Q49 (2SC5066), and low-pass filter network, then is applied to the UHF “sub” first mixer Q52 (2SC5066) along with the 21.7 MHz UHF “su

35、b” first local signal from the UHF “sub” VCO. The UHF “sub” first local signal is generated between 408.3 MHz and 428.3MHz by the UHF “sub” VCO Q13. The 21.7 MHz UHF “sub” second IF signal applied to VHF receiving circuit. The UHF “sub” signal is amplified, filtered, and demodulated, etc., by the VH

36、F receiving circuit, described previously. 6) VHF Squelch Control When no VHF carrier is being received, noise at the output of the detector stage in IC3 is amplified and band-pass filtered by the noise amp section of IC3, then passes through the noise adjust VR (VR8) to CPU. The resulting DC voltag

37、e is applied to pin 88 of main CPU IC19 (M30624FGAGP), which compares the squelch threshold level to that which set by the font panel VHF SQL knob. While no carrier is received, pin 55 of IC19 remains “high,” turning on the squelch switch Q108 (DTC363EK) to disable audio output from the speaker. 7)

38、UHF Squelch Control When no UHF carrier is being received, noise at the output of the detector stage in IC5 is amplified and band-pass filtered by the noise amp section of IC5, then passes through the noise adjust VR8 to cpu. The resulting DC voltage is applied to pin 90 of main CPU IC19, which comp

39、ares the squelch threshold level to that which set by the front panel UHF SQL knob. While no carrier is received, pin 56 of IC19 remains “high” turning the squelch switch Q109 (DTC363EK) to disable audio output from the speaker. 7 8) Transmit Signal Path The speech signal from the microphone passes through the MIC jack CN601 to AF amplifier IC601 (M5218FP) on the FRONT UNT. The amplified speech signal is subjected to amplitude limiting by IC601 (M5218FP), then passes through the Front interface jacks CN602 and CN2 to MAIN Unit. On the MA