BC-603A_DM_serv_TM11-4033_1945.pdf

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1、l/F A R J) PAR T J E iV T T l1J ll-J-033 RADIO RECEIVERS BC-603-A -C -D , , , -AM -CM AND-DM , , TT.lRNING: The material forming the subject matter of this 111(IIUal (document) is the /roperty of the United States Govctnment alid it is printed and distributed sole!y fe,! the use of the militar:y, na

2、val and civilian personnel of the War and Navy Departments, and may not be published or reProduced in whole or in i)(lrt in allY maniler or form (exeept by lawful copright hoMers who Iilay reproduce the:r copyrighted lrltlterial in its urigill!l fo!n) except tt/O! sj,ecific 0/,/,107:01 by uuthori :J

3、ed lIlilitary public relations a,enrieo. 1fT A R D EPA R T .L1J E lT T J U L 1 9 4 5 Cnitfd States Governmfllt Printill!/ OjJiu TV ashillf/tOll : 194j ii V-R DEP-RTiIElT VASHIGTOK 25, D. C, 31 July 19tS TiI 114033, Radio Rcceinrs BC()03-, C, JJ, ,r. CIJ, and DI, Repair Illstructiulls, is puhlishul f

4、(ll the informatiun and guidance of all (oncernecl. OrFTCLL: EDYV,-RD F. ITS ELL 1 afor General lctin! The Adjutant GLJlcral DrSTRlBCTLO.: : G, C. IARSILLL Chief of Staff AAF (5); LGF (5): LSF (2): T of Opn (5); Dept (5): Base Comd (5); Island Comd (5) : Dei Comcl (2) ; ,-r111 S Di L-SF (1); Tech S

5、(2) ; PC PE (2); Dep 11 (2); Gen OYersea SOS DCI (2); Pro Dist 11 (2): (ell DGS Lib (5); Lab 11 (2): Rep Shop 11 (2): (5) : CHQ (2). Three (3) copies to each of the following: T/O 111.:;: 1l-I-7: 1l107; 11-127; 11147S; 11587: 11592: 11597. Refer to Fl1 216 for explanation of distribution formula. CO

6、NTENTS Paragraj)h SECTION I. DESCRIPTION OF RADIO RECEIVERS BC-603-A, -C, -D, -AM, -CM, AND -DM. General . . Performance characteristics . . Condensed circit analysis . . II. DIFFERENCES BETWEEN MODELS. 2 3 Operational differences . 4 Design differences . 5 III. INITIAL REPAIR PROCEDURES. General .

7、. Removal of tubes . . Removal of chassis parts . . Cleaning, inspecting, and lubricating Ch;lssis assembly . . Cleaning, inspecting, and testing removed parts . . IV. PRELIMINARY TROUBLE-SHOOTING PROCEDURES. General . , . , . . Dynamotor continuity tests . . Receiver input resistance tests . . Repl

8、acement o removed parts . . Operational test . . Voltage and resistance check V. ALIGNMENT PROCEDURE. General . , . , . . Alignment procedures . . Alignment using an f-m signal generator . Alignment using an a-m signal generator Alignment usil1g a good receiver . , Alignment using a good transmitter

9、 VI. DETAILED TROUBLE-SHOOTING PROCEDURES. Signal source . . Signal tracing nsing an f-111 signalgcnerat()r . . Sign:d tracillg using a good receier . . Signal !racii;g u:;iclg a gooc1 transmitter Signal tracing using an a-111 signal generator VII. FINAL TESTING. Over-an test requirements lIoistllre

10、llroofing, fungiproofing, ;md refini11illg Operatiunal check . . VIII. INDIVIDUAL STAGE AND CIRCUIT REPAIR DATA. 6 7 8 9 10 II 12 13 1-+ 15 16 17 18 19 20 21 22 23 2-+ 25 26 27 General. . . . . . . . . . . ., . . . . . 31 Parts list for r-f amplifier stage, VI . ., . . . . . . . . . . 3.2 Parts list

11、 ior modulator stage, V2 . . Parts list for r-f oscillator :-;tage, -3 . . Parts list for first i-I amplifier, V.J. . . Parts list for second i-I amplifier stage, V . , Parts list for limiter stage, :6 . . . . Parts list for detector (discriminator) stage, V7 . . Parts list f(r firt audio-amplifier

12、stage, V1O . . Parts list for second audio-amplifier (:l;.;e, VB Parts list for delayed a-c circult, V9 . . Part:; li:-;t for sCjl1elch circuit, V9 . Parts list for i-f osci11ator stage, VI0 . ,. IX. SUPPLEMENTARY DATA. Parts identification . . 33 3-+ 35 3) 37 3:- 30 -to 41 42 .+3 44 Fagc 3 3 4 J J

13、6 8 13 13 13 1.J. 1.+ 5 17 17 Ix 20 21 23 20 2() 2() 30 30 3() .J.O 40 41 41 42 43 4-t 45 -16 47 -If -If) 50 51 -) J_ 53 iii WARNING HIGH VOLTAGE is used in the operaHon of this equipment. DEATH ON CONTACT may result if safety precautions are not observed. v Figure 1. Radio Receiver BC-603-(* )-frol

14、lt view. vi SECTION I DESCRIPTION OF RADIO RECEIVERS BC-603-A. -C. -D. -AM. -CM. AND -DM* 1. General Radio Receiver BC-603-(*) (figs. 1 and 2) is a component of Radio Sets SCR-508-(*), SCR- 528-(*), SCR-538- (*), AN /VRC-5 and AN /TRR-3. The receiver provides frequency-mod ulated radiotelephone rece

15、ption facilities for car, platoon, company battalion, and regimental com manders, and for staff officer and commanders in higher echelon. The receiver may be installed and operated in combat vehicles such as tanks, scout cars, half-tracks and command cars, or any other author ized vehicle. Official

16、nomenclature followed by (*) is used to indicate all models of the item of equip ment included in this Technical lVlanual. Thus Radio Receiver BC-603-(*) represents BC-603-A, -C, -D, -A lVi , -CM, and -DlV1. FigLtre 2. Radio Receiver BC-603-(* )-oblique rear view. 2. Performance Characteristics Freq

17、uency range . . . . . . . . 20.0 to 27. 9 mc. N umber of preset channels . 10 Power supply . . . . . . . . . . . 12- or 24-volt ve- hicular battery. Control of channeL . . . . . hcal only. Sensitivity . . . . . . . . . . . . 1,uv. Intermediate frequenc: (nominal) . . . . 2.65 mc. Band width . . . .

18、. . . . . . . . 80 kc. Power output, speaker . :2 watts. Power output, headset . . . 0.2 watt. Call signal . . . . . . . . . . . . . . lamp. Noise suppression . . . . . . . squelch. Battery drain, 12-volt supply . . .+ amperes. Battery drain, 24-volt . supply . , . :2 amperes. 3. Condensed Circuit A

19、nalysis A block diagram of Radio Receiver BC-603-(*) lS shown in figure 3. The receiver uses the superhetero dyne principle of operation. The high-frequency cir cuits include one stage of tuned radio-frequency amplification (VI ) , and modulator (V2), ar:d a radio-frequency oscillator (V3) . The int

20、ermediatc frequency amplifier comprises two stages (V 4 and VS) , the second of which (VS) provides some limit ing action on strong signals. The limiter stage (V6) not only functions as a limiter onmoderate signals, but it also reduces amplitude modulation. The de tector, or discriminator (V7) is fo

21、llowed by two *See TM 11-600 for installation, operation, and other maintenance data on this equipment. stages of audio-frequency amplification (VIO and V8). An intermediate-frequency oscillator (VIO) permits checking the receiver tuning. A single dual purpose vacuum tube (VIO) functions as the firs

22、t audio stage (VIO) and the intermediate-frequency oscillator (VIO) . A second dual-purpose tube (V9) provides delayed automatic volume control (V9) and squelch (V9), which suppresses noise by dis abling the receiver output when no signal is being received. A tube chart follows. TUNING CONTROL r-l /

23、 .-.:-1-. DC OELAYED AVC VOLT.lGE Circuit designation VI V2 V3 V4 VS V6 V7 VB JAN designation VTNo. Function 6AC7 . VT-112 . R- amplifier. 6AC7 . VT-112 . Modulator. 6J5 . VT -94 . R- oscillator. 12SG7 . VT-209 1- amplifier. 12SG7 . VT-209 . 1- amplifier. 6AC7 . VT -112 . Limiter. 6H6 . VT -90 . Det

24、ector (di- criminator) . 6V6GT . VT-107-A Second a- amplifier. V9 6SL7GT VlO . 6SL7GT VT-229 VT-229 Avc and squelch. First a- amplifier and i- oscillator. LOUD SPEAKER TLI8221 Figure 3. Radiu Recci7.1?r jC -603-(* )-bioc/, diaural11. 2 SECTION II DIFFERENCES BETWEEN MODELS 4. Operational Differences

25、 There are no operational differences between the various models of Radio Receiver BC-603-(*) . 5. Design Differences a. In some models of Radio Receiver BC-603- .(*), resistors R94, R95, and R96, have been changed III order to increase the sensitivity of the receiver at the minimum setting of the S

26、EN SITIVITY con trol and to insure that the SQUELCH control is operative over the entire sensitivity range. See dia gram of squelch circuit, figure 35. b. Some models of Radio Receiver BC-603-(*) have a pivoted latch to hold down the PUSH TO TUNE button when needed. Caution: The latch must be diseng

27、aged and left free when the push-button selector is used; other- Wise, the added friction may prevent accurate re setting of the tuning capacitor, and an abnormal strain will be put on the mechanism when the se lector push button is pressed. c. In Radio Receiver BC-603-Dl1 the TUNE OPERATE switch is

28、 a two-circuit switch. This switch when set to TUNE causes the receiver beat oscillator to operate and open the circuits from trans mitter relay S 103 to prevent disabling of the receiver during tuning adjustment. d. The TUNE-OPERA TE witch D5 mounted on the front panels of Radio Receivers BC-603A -

29、C, and -D has been changed. It is (in modified receivers only) a two-circuit type switch (Cutler Hammer No. 8284) or equal. After this modification is made on Radio Receivers BC-603-A -C and -D they become Radio Receivers BC-603-AM, -CM: and -DM. 3 SECTION III INITIAL REPAIR PROCEDURES 6. General No

30、te. Before making any repairs or adjustments, all authorized Modification Work Orders should be applied. See FM 21-6 for list of applicable Modification .Fork Orders. A step-by-step procedure is presented in this and the following sections for the repair and maintenance of Radio Receiver BC-603-(*).

31、 The succeeding sec tions go into detail on shop procedures for align ment, trouble shooting, signal tracing, etc., and also provide all the necessary charts, diagrams, and in formation. The initial repair procedure describes the method of removal of tubes and other easily removable parts; the clean

32、ing, inspection, and test ing of the chassis assembly; the cleaning, inspecting, testing, and lubrication of removed parts; and the repair or replacement of parts found to be faulty. The tool, test, and cleaning equipment required for the repair of Radio Receiver BC-603-(*) are shown in table I. Tab

33、le 1. Itm Adapter FT-384-( ). Output meter. V oltohmmeter. Tool, test, and cleaning equipment Description Switch box for connecting various parts of receiver circuit to facilitate alignment procedure. (See figs. 20, 21, and 22.) Input impedance of 5,000 ohms or more, O-to 60-volt range, as well as s

34、everal lover ranges; such as the output meter (fig. 21) from Test Set 1-56-(*), or equivalent Resistance ranges up to 5 megohms (meg) ; voltage ranges up to 300 volts in several scales, alternating current and direct current; input resistance, direct current, at least 10 meg. Use volt-ohmmeter 1-107

35、-(*), or equiva lent. If volt-ohmmeter 1-107-(*) is not available, make voltage measure ments with a voltmeter having a sen sitivity of at least 1,000 ohms per volt, and ranges up to 300 volts direct current, such as the voltmeter from Test Set 1-56-(*), or equivalent. It is still essential to have

36、an ohmmeter having ranges up to 5 meg. Itm Mounting FT-237-(*) . Capacitor. Resistor. Tube checker. Cord, CD-786. Assorted hand tools. Description Connects Radio Receiver BC-603-(*) to a battery power supply and insures proper interconnection of the units when used in the complete radio sets. See fi

37、gures 18 and 19 for view, and schematic diagram of Mounting FT -237-(*). 0.006 microfarad (mO, 300 volts direct current with suitable clip con nectors. 1,000 ohms, 2 watt, equipped with insulated clip connectors. Unit of Test Set 1-56-(*), or equiva lent. Connects 12-or 24-volt battery to receiver.

38、Brush. I eamels-hair, V-t-inch round. Solvent, dry-cleanint Bellows. Small, hand-operated. Signal generator. Frequency-modulated (f-m), capable of operating in the 2-to 3-mc band, and in the 20.0-to 28.0-mc band. The audio frequencies available for modu lation should be 150, 400, 1,000, 2,500, and 5

39、,000 cycles per second. The sig nal generator should be capable of supplying the above audio frequencies directly. If an f-m signal generator is not available, one of the following, substitutes which is listed in the order of preference may be used: Radio Receiver BC-603-(*) in good condition, or an

40、other f-m receiver in good condition, capable of operating in the frequency range from 20.0- to 28.0-mc and capable of supplying an intermediate fre quency of 2.6S-mc. Radio Transmitter BC-604-(*) in good condition, or another f-m transmitter in good condition, capable of operating in the fre quency

41、 range from 20.0- to 28.0- mc and capable of a frequency division of at least 75 kc. An amplitude-modulated (a-m) sig nal generator capable of operat ing in the 2- to 3-mc band, and in the 20.0-to 28.0-mc band. 7. Removal of Tubes a. Remove the dust cover as directed in para graph 8. b. The space ar

42、ound a vacuum tube is often limi ted. (See figs. 5 and 11.) Therefore, use a tube extractor or with the fingers rock the tube gently while pulling up. Note. Immediately upon removal, label each tube clearly so that it can later be replaced in the socket from which it vas taken. 8. Removal of Chassis

43、 Parts The removal of the cover, dynamotor, fuses, and CALL SIGNAL lamp is described below. a. COVER REMOVAL. Place the receiver, panel downward, on a smooth surface. Turn the Dzus fastener at the rear of the cover one-quarter revolu tion counterclockwise and then slide the cover off. b. DYNAMOTOR R

44、EMOVAL. Release the four mount ing bolts in the corners of the dynamotor mounting plate (fig. 8) and lift the dynamotor (figs. 6 and 7) fro111 the receiver. c. FFSE RE2IQVAL. Tvo fuses, labeled FCSE and SPARE, are located within the panel guard, below the speaker. (See figs. 1 and 7.) Remove the fus

45、es by inserting a screw driver in the slotted fuse hold ers and turning counterclockwise. The fuses can easily be extracted from their holding sleeves. FiiJure 4. Radio Receizer BC-603-* )-left-side interior view. 5 Figure 5. Radio Receiver BC-603-(* -right-side interior view. d. CALL SIGNAL. LAMP REIOVAL. Unscrew the jewel guard of the CALL SIGNAL lamp on the front panel (fig. 9), and remove the bayonet-base lamp by pushing it in and turning it