SAIT_Siemens_745E310A_serv.pdf

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1、 ELECTRONICS 745EaI c 0 N T E N T S 1. GENERAL . 2. TECHNICAL DATA .*.*. 2.1 - FREQUENCY RANGE .*. 2 p 2 . 2 - TUBE COMPLEMENT .* * * *. 2.3 - SCALE GRADUATION.V 3 2.4 - RF INPUT .*.*.* *.* J 2.5 - INTERMODULATION . 2.6 - AUDIO OUTPUTS . b 2.7 - POWER SUPPLY .*. 6 2.8 - DIMENSIONS AND WEIGHT .*.* 6

2、. 7 3. BASIC FUNCTION.*. 3.1 -BANDS 1 AM) 2 .*. 7 3.2 -BAUDS 3 AND 5 .*.*. T . 8 3.3 - BAM) 4 . n 3.4 BANDS 6 TO 12 .*.*.*. g 3 * 5 - BLOC DIAGRAM . . 3.6 - FREQUENCY SCHEDULE .*. 9 . 4, FUNCTIONS OF THE SUBASSEMBLIES . 10 . 11 4.1 - RF SECTION . 4 . 2 - CALIBRATING OSCILLATOR .“* 11 4.3 - FIRST MIX

3、ER STAGE AND FIRST OSCILLATOR . 12 4.4 - DOUBLER * .*.* 13 4.5 - INTERMEDIATE FREQUENCY 1, 2nd MIXER STAGE AMD 2nd OSCILLATOR .*. 4.6 - INTERMEDIATE FREQUENCY 2, DEMODULATION, GENERATION OF THE AUTOMATIC CONTROL VOLTAGE . 4.7 AUDIO STAGE, NOISE LIMITEH . . 15 4.8 - AUDIO STAGE AND FINAL STAGE . 15 4

4、.9 - TUNING INDICATION .*.*. 4,10- POWER SUPPLY UNIT . . . SAIT j f e f r f l * 0 g A . | ELECTRONICS 5, .la yout .*. 16 6. OPERATION . 18 6.1 - PROCEDURES PI LOR TO PLACING INTO OPERATION. 18 6.2 - PLACING THE RECEIVER INTO OPERATION . 20 7 MAINTENANCE . 21 7.1 - CLEANING, SERVICING, SUPERVISING. 2

5、1 7-2 - CHECKING THE CRYSTAL OSCILLATOR . 22 7.3 - REMOVING THE FRONT P A N E L. 23 74 - REPLACING PARTS . 24 7.5 - ALIGNMENT . 25 7.6 - ALIGNMENT OF FREQUENCIES FOR. TRACKING. 30 7.7 - GUIDING VALUES FOR THE CORE POSITIONS,.- 31 7.8 - TROUBLE SHOOTING . *. 32 8. COMPONENTS L I S T. 36 8 .1 - INPUT

6、SECTION (STAGE 1 TO 4) . 36 8.2 - FREQUENCY CONVERTER SECTION (STAGES 5, 6 and 7)* 43 8.3 - AMPLIFIER SECTION (STAGES 8 TO 1 4) . 46 8 .4 - POWER SUPPLY SECTION (STAGE 15) . 51 31 ELECTRONICS 745 Ea .1 1 in its shortwa ve ba na s it opera tes with double frequency conversion. .The frequency ba nds a

7、 re se lected with pushbuttons. For incrementa l control of receiving frequen cies a bove 15 Mc/s the second oscilla tor ca n be detuned by up to 100 Kc/s in ga nged tuning with the circuits of the first intermedia te fre quency. Ea ch 100 Kc/s sca le division on the ma in sca le ca n be checked a g

8、a inst a built-in crysta l spectrum genera tor. Tempera ture-compensa ted la yout of the frequency-deter mining sta ges, tempera ture-resista nt ma teria ls a nd components a nd impregna tion of moisture-sensitive components ma kes the receiver wide ly immune to clima tic conditions a nd suita ble e

9、ven for deep-sea na viga tion. The receiver ma y be opera ted from AC or DC ship s ma in or from 24 volts stora ge ba ttery. It ma y be supplied either a s a sepa ra te unit conta ined in a robust meta l ca binet for bench mounting or be incorpora ted in the SAIT console a s Ma in or Emergency recei

10、ver. 2 - TECHNICAL DATA Types of reception : A1 Unmodula ted telegra phy in a ll frequency ba nds _ _ . _ A2 Modula ted telegra phy in the frequency ba nds between 170 a nd 30.300 Kc/s A3- Telephony in the frequency ba nds between 170 a nd 30.300 Kc/s ELECTRONICS freq uency RANGE Ba nd 114 to 21 Kc/

11、s (xx) 2 85 to175 Kc/s 3 170 to350 Kc/s 4 340 to 730 Kc/s 5 720 to,1540 Kc/s 6 1500 to3100 Kc/s (x) 7 3100 to6300 Kc/s (x) 86000 to 0,200 Kc/s (x) 9 9700 to 15,200 Kc/s (x) 10 14,700 to 20,200 Kc/s (x) 11 19 ,7 0 0 to 25,200 Kc/s (x) 12 24,700 to 30,200 Kc/s (x) The up to 100 Kc/s tha t ca n he set

12、on the frequency interpola tor sca le ha ve to he a dded to the frequency va lues rea d on the ma in sca le. 14 to 25 Kc/s optiona l, TUBE COmMENT Europea n typeU.S.A.type 4 tubes EF 93 6BA6 3 tubes EK 90 6BE6 4 tubes ECC 821 2AU7 . . 2 tubes EAA 91 or EB 91 6 AL5 1 tube EL 90. 6AQ5 I a i I a 1 * EL

13、ECTRONICS 745Ea3 1 tubeEM 34 6 CD 7 1 sta bilizer tube (input protection) 108 C10B 2 2.3- SCALE GRADUATION in ba nd 1 with 1-kc/s divisions 2 with 5-kc/s divisions 3 with 10-kc/s divisions 4 with 10-kc/s divisions 5 with 20-kc/s divisions in ba nds 6 to 1 2 with 100-kc/s divisions with incrementa l

14、control 100 kc/s per mra 1 kc/s per ra m 1 . 5 kc/s per mm 3 kc/s per mm 5 kc/s per mm (a t a udio output) Ba nd Cla ss-of- emission signa l-t o-noi se ra tio (db) Input M F ( ) 1A1 10 3.0 2 to 4A1 10 2 .0 6 to 12A1 10 0 ,6 4 a nd 5A3 20 40 6 to 12A3 20 10 Ra nge of control for the pitch of the hea

15、t note = + 3000 c/s Audio ga in control ma nua l RF iin control a utoma tic (AVC)or ma nua l Va ria tion of the a udio output volta ge With a cha nge in RF input volta ge from 10 to 50 mv , 4 dh Cha rging time consta nt of the AVC system With cla sses-of-emission A1 a nd A2/A3 0.1 sec Discha rge tim

16、e consta nt of the AVC 0 .5 to 1 sec 0. 1 sec With cla ss-of-emission A1 With cla ss-of-emission A2/A3 Noise limiting a ction continuously a djusta ble a nd disconnecta ble Ba ndwidth of the a udio a mplifier At the 3-db-down points With respect to the 1 kc/s response Distortion fa ctor with 1.5 a u

17、dio output Unweighted noise a t the loudspea ker With full a udio ga in a nd minimum RF ga in Corresponding to a signa l-to-noise ra tio 300 to 5000 c/s 1C% 90 mv . Ma ins ! Via built-in power sypply unit, ma y be a djusted. for 11 0 12 5 220 250 volts opera tion a t 40 60 c/s Input power : a bout 1

18、00 VA. DC Ma ins ; Receiver fitted a s independent unit opera tion from DC Ma ins 110 220 volts or 24 volts stora ge ba ttery via vibra tor, inverter or rota ry converter. Receiver included in SAIT Console ! When the ships ma ins is DC, the receiver is powered by the Console s Ma in Converter 110 vo

19、lts single pha se output. Permissible volta ge va ria tion of the power supply + 10 % 2.8.- DIMENSIONS_AND_WEIGHT Front pa nel (When the receiver is included in SAIT Console) Width :52 cm Height :30,4 cm. In meta l ca binet with shock a bsorbers (When fitted a s independent Unit) Width :55 cm Height

20、 : 350 cm Depth :38 cm Weight : a pprox. 35 Kgs. SAIT ga ctWtig4 ELECTRONICS 3- BASIC FUNCTION The receiver performs in different wa ys in the twelve ba nds. Four different f u n c t i o n al pa tterns ca n be distinguished; they a re a sso cia ted with the va rious ba nds a s follows : Functiona l

21、pa ttern A with ba nds 1 a nd 2 B with ba nds 3 a nd 5 C with ba nd 4 D with ba nds 6 to 12 The differences by reference to functiona l circuit dia gra ms showing merely the suba ssemblies a ctiva ted a t the time, not however switches a nd rela ys, a re described herea fter. i ;31 .- BANDS 1 _ AND

22、2 (See DWG 4-92 Fig. 2) In the ba nds 1 a nd 2 only signa ls of cla ss A1 a re to be received. The set opera tes with single frequency conversion. The fre quency of the tuna ble first oscilla tor is 50 kc/s a bove the receiving frequency. The intermedia te frequency of 50 kc/s so genera ted in the m

23、ixer sta ge is doubled in the following sta ge to give 100 kc/s, i.e. ra ised to the frequency position of the following.IF a mplifier. This IF signa l pa sses trough the second ha lf of a qua dru ple-tuned ba nd filter. Subsequently the IF cha nnel splits into a na rrowba nd a nd a wide-ba nd bra n

24、ch. In the wi de-ba nd bra nch the AVC volta ge is produced; in the na rrow-ba nd bra nch the A1 signa l is a mpli fied once more a nd fina lly tra nsla ted to the a udio position with a ca rrier differing but slighty from 100 kc/s. Audio sta ges with noise limiter a nd a fina l sta ge a mplify the

25、a udio signa l (difference of intermedia te frequency a nd va ria ble heterodyning frequency) to be output level desired. 3.2- BifflDS 3 AND 5 ( See DWG 4-62 Fig. 3) Also in these ba nds the receiver opera tes with single fre quency, conversion, but the first oscilla tor frequency is now 100 kc/s a

26、bove the receiving frequency so tha t the 100-kc/s IF signa l comes a bout a lrea dy in the first mixer sta ge. It tra vels trough both ha lves of the qua druple-tuned filter. Subsequently the signa l pa sses the sa me suba ssemblies a s with ba nds 1 a nd 2. The na rrow-ba nd IF a mplifier bra nch

27、(Dwg.4.9.1) heterodynes a nd demodula tes the signa l (a node bend detection) in receiving signa ls of cla ss A1, the upper wideba nd IF a m plifier bra nch supplying the AVC . volta ge. In the reception of signa ls SAITELECTRONICS 745Ea : 8 i of cla ss A2/A3 the upper IF a mplifier pa th effects th

28、e demodula tion (diode detection); in the lower IF a mplifier pa th the AVC volta ge is ga ined. 3.3.- BAKD_4 (See DWG 4-6.2 Fig. 4) -In this ha nd the receiver opera tes with double frequency conversion with the second oscilla tor set a t a fixed frequency. The first oscilla tor is of va ria ble fr

29、equency a nd opera tes 118 0 kc/s a bo ve the receiving frequency. The IF1signa l of 1180 kc/s so genera ted in the first mixer sta ge is a pplied to the second mixer sta ge via a double-tuned filter. The fixed-tuned second oscilla tor opera tes a t 1280 kc/s tha t a n IF signa l of 100 kc/s comes a

30、 bout in the second mixer sta ge. The qua druple-tuned filter a nd the sta ges followingin the signa l pa th equa l those for ba nds 3 a nd 5* 3.4- BANDS 6 TO 12 (See DWG 4-6.2.Fig. 5) The receiver opera tes with double frequency conversion a lso in these ba nds. If it is tuned with the ma in sca le

31、 a lone, the electrica l conditions a re the sa me a s described for ba nd 4, With the incrementa l tuning sca le, however, (frequency interpola tor) the IF1 filter a nd the second oscilla tor ca n be ga nged- tuned trough up to 100 kc/s, their frequency difference a lwa ys equa l ling the consta nt

32、 second intermedia te frequency (see .a lso pa ra gra ph 4-3.6). Since the incrementa l tuning control does not a ffect the fre-* quency of the first oscilla tor, the receiving frequency cha nges to the sa me extent (but in opposite direction) a s the first intermedia te frequency. The RF circuits n

33、eed not be returned, for they a re suffi- ciently wideba nd. The cla ss-of-emission switch va ries the couplings in the qua druple-tuned filter of the IF2 a mplifier a nd thus the ba nd width a ccording to the three positions A1 , A2/A3 Na rrow a nd 2/3 Wide” . The following circuitry a ga in equa l

34、s tha t for the other groups of ba nds. 3*5 BLOCK DIAGRAM _ # The functiona l circuit dia gra m (Dwg.4.9.1) shows the. ba sic interconnection of the individua l receiver sta ges a nd control elements. . At the a ntenna input the protective mea sures a ga inst overloa d of the input circuits a re sym

35、bolized (neon la mp, protective la mps, cut-off rela y A)* The input signa lrea ches the RF preselector SAIT | f o e t t 0 R i c 4 ) ELECTRONICS sta ge which is switched to the ba nd desired a t the time with twelve pushbuttons. By pressing,.the ca llibra ting key a signa l of 100 kc/s or a multiple

36、 thereof ca n be a pplied from the ca libra ting oscilla tor to the control grid of the first tube. In this procedure the a ntenna , the BFO a nd the incrementa l frequency control a re a utoma tica lly disconnec ted. Conta cts of the rela ys B a nd C lea d the signa l from the first mixer sta ge vi

37、a the doubler to the second ha lf of the qua druple- tuned filter (lP2),.or directly to the input of the qua druple-tuned filter, or via IF1-filter a nd the second mixer sta ge with second os cilla tor to the input of the qua druple-tuned filter. The opera ting con dition of the rela ys B a nd C dep

38、ends on the ba nd selected with the pushbuttons. The qua druple-tuned filter feeds into a na rrow-ba nd a nd a wide-ba nd IF sta ge. In cla ss-of-emission A1 the na rrow-ba nd (lower)IF pa th supplies the signa l Volta ge which is heterodyned with a frequen cy of a bout 100 kc/s in the A1 -demodula

39、tor, while the AVC volta ge comes a bout a t a diode behind the wide-ba nd (upper) IF pa th. In cla ss A2/A3 this diode supplies the demodula ted signa l, a nd the other diode which is fed by the lower IF sta ge, derives the AVC volta ge. The AVC volta ge controls the preselector sta ge, first mixer

40、 sta ge, second mixer sta ge a nd la st IF sta ge. The ga in ca n a lso be a djusted by ha nd with the control RF Ga in” . A common switch for cla ss-of-emission a nd ba ndwith con nects the demodula tor a ctiva ted a t the time to the volume control which is followed by the a udio section with nois

41、e limiter a nd fina l sta ge. 3.6.- FREQUENCY SCHEDULE Ba nd Receiving frequency in kc/s Frequency of 1st oscilla tor in kc/s 1st inter media te frequency in kc/s Frequency of 2nd oscilla tor in kc/s 114 to 2164 to 71 (5 0)- 285 to 175 135 to 225 (50)- 3 170 to 350270 to 450(10 0)- 4 34 0.to 7301520

42、. to 191.0118 01280 5 - 720 to 154 0820 to 1640(10 0)- ELECTRONICS 745Ea10 6 150 0 to 310 0 + (0 to 10 0) 2680 to 4280 118 0 (0 to 10 0) 1280 -( 0 to 10 0) 7 310 0 to 6300 + (0 to 10 0) 4280 to 7480 118 0 - ( 0 to 10 0) 1280 -(0-to 10 0) 8 6000 to 10 ,2 0 0 + (O to 10 0) 718 0 to 11 ,3 8 0 118 0 - (

43、 0 to 10 0) 1280 - ( 0 to 10 0) 9 9700 to 15 ,2 0 0 + (0 to 10 0) 10 ,8 8 0 to 16 ,3 8 0 118 0 - ( 0 to 10 0) 1280 -( 0 to 10 0) 1014 ,7 0 0 to 20 ,20 0 + (0 to 10 0) 15 ,8 8 0 to 2 1,3 8 0 118 0 - ( 0 to 10 0) 1 0 -* ro c l CO 0 O 0 3 11 19 ,7 0 0 to 25 ,2 0 0 + (0 to 10 0) 20 ,8 8 0 to 26,380 1180

44、 (0 to 10 0) 1280 - ( 0 to 100. ) 12 24 ,7 0 0 to 30 ,20 0 + (0 to. 10 0) 25,880 to 31,380 118 0 - ( 0 to 10 0) 1280 - ( 0 to 10 0) / 2nd intermedia te frequency : 10 0 kc/s for ea ch ba nd Frequency doubling : for ba nds 1 a nd 2 only A . - FUNCTIONS OF THE SUBASSEMBLIES j 4.1 - RESECTION ( See DWG

45、.4.9.4, (sta ges 1 a nd. 3) A neon sta bilizer tube T101 (1 Ro?) is connected a cross the a ntenna termina l of the device to prevent overvolta ge a cross the a ntenna coils. The a ntenna lea d pa sses via conta ct a ll.2 of rela y K-101. This rela y is controlled via de keying line of the tra nsmitter of the sa me sta tion for the t