BC-669A_B_C_D_serv_TM11-4058_1945.pdf

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1、 ,. , . , . . _, . ,-: 7.:. MANUAL ElVER ANDT MITIERS BC-669-A,-B,-C,D, I , ., . -BM,and . CM REPAIR IN WAR DEPAJTMENT DECEMBER 1945 , : i I I i CONTENTS SECTION I. DESCRIPTION OF RADIO RECEIVER AND TRANSMITTERS BC-669-I*l. General Ov r-ail system funct ion II. DIFFERENCES BETWEEN MODELS. Difference

2、s between models of Radio Receiver and Transmit tcr DC- 669-(*) . . . . . . . . . . . . . E lect.,ical and mechanical eli ff renccs . . . . . . Ill. INITIAL REPAIR PROCEDURES. General . . . . . Method of starling repairs . . . . . . . Tools, lest and cleaning quipment . Removal of lubes and other pl

3、ug-in parts . . . . . . . . Chassis cleaning, inspecting, and lubricating . . . . . . . Cleaning operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T nspection procedure . . . . . . . . . . . . . . . . . . . . IV. PRELIMINARY TROUBLE-SHOOTING PROCEDURES. General . . . . . . . . . .

4、 . . . . . . . . . . . . . . . . . . . . . . . . . . Resistance test of I ower Supply Unit I)E-110-(*) . . Turning on Receiver and Transmitter l3C- 669- (*) . . . Volta e tests . . . Operating test . . V. ALIGNMENT PROCEDURE. General . . . . . . Alignment o( receiver . . . . . . . . . . . . . . . 1-

5、f alignment . . R-f alignment . , . . B- -o alignment . . . . . Transmitter preset ting . . . . . . . . Final adjustment . . . . . . VI. DETAILED TROUBLE-SHOOTING PROCEDURES. Voltage and resistance measurements at tub sockets . . Signal tracing . . . . Signal sub tilUtion . . . . Measuring individua

6、l stage gain . . . . . . . . . . . . If oistureproofmg, fungi proofing, and refinishing . . VII. FINAL TESTING. Alignment test . . . . . . . . . . . . . . . . . . . . . . . . . . . Signal-to-noise test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sensitivily test . . . . . . . . . .

7、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Selectivity test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T1ansmitter power output and modulation check . . . Operational test . . . . . . . . l 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

8、 30 31 32 33 34 35 1 2 5 5 9 9 9 9 11 11 12 14 14 15 17 17 18 18 18 18 19 19 21 23 23 32 33 34 34 35 35 35 36 36 37 iii I VIII. INDIVIDUAL STAGE AND CIRCUIT REPAIR DATA. R-f amplifier stage . . . . . . . . . . Mixer or converter stage . . . . . . . . . . . . . . . . . H eterodyne o cillator stage .

9、. . . . . . . . . 1-f amplifier stage . . . . . . . . . . . . . . . . . Second detector, noise limiter, and a-v-e stage . . . . Audio-voltage amplifiet stage . . . . . A- power-amplifier stage . . . . . . . . . . . . . Receiver b-f -o stage . . . . . . . . . . . . . . . . . Transmitter oscillator st

10、age . . . . . R-f power-amplifier stage . . . . Antenna coupling stage . . . . . Low-level microphone voltage amplifier stage . . . . . . . . . . . A-f power-amplifier stage of transmitter modulator . . . IX. SUPPLEMENTARY DATA. Initial repair procedure chart Noisy receiver . . . . . . iv Paragraph

11、36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Pag 38 42 43 46 49 51 54 56 59 62 66 68 70 75 75 SAFETY NOTICE This equipment u es h1:gh voltages which are dangerous to li.fe. Electrical inter- lock switches are provided (or your protection. They remove the high d-e voltage to the output circuits in th

12、e transmitter when Lhe hinged doors of the cover are open or when either the cover or the back is removed. Always be sure that ,back, cover, and ;over doors are closed bejo1e ajJplying fJlate jJower. When the transmitter is in operation exL?emely high r-f voltages are present in and around the anten

13、na tuning unit, all its connecting leads, the antenna and the antenna insulator. You can get dangerous bnrns from arcs caused by touching the antenna cinwit. Be careful! Do not attempt to make an adjustment unless you are thoroughly familiar with this equipment. t v ANTENNA LOADING . COIL ADJUSTMENT

14、 TRANSMITTER P.A. PLATE TUNING OPERATING CHANNEL- SWITCH . ON-OFF - SPEAKER SWITCH RECEIVER A. F. RECEPTACLE PL3 FOR CORD CD-513-( *) , . OR REMOTE CONTROL UNIT RM-21-(*) f RECEIVER D.C. MILLIAMETER M2 FOR READING P. A. PLATE, MOD. PLATE, AND P. A . GRID CURRENT STATIC FILTER SWITCH RECEIVER SWITCH

15、1-NOISE CONTROL METER SWITCH RECEPTACLE PL2 FOR CORD CD-515(*) I TLI9679 j Figtre 1. Radio Receiver and Tmtwnitter BC-669-(*), front panel view with e;rplanatory data. vi SECTION I DESCRIPTION OF RADIO RECEIVER AND TRANSMITTERS BC-669- (*)* 1. General a. ExPLANATION OF SYMBOL. Official nomencla- tur

16、e followed by (*) is used to indicate all models of the item of equipment included in this Technical Manual. Thus :Radio Receiver and Transmitter BC-669-( *) represents Radio lecei ver and Trans- mitters. BC-669-A, -B, -C, - D, -AM, -BM, anc.l -CM, which are treated together in this manual. b. PuRPO

17、SE. Radio Receiver and Transmitter BC-669-(*) (fig. 1) is the radio component of Radio Set SCR-.543-(*). It provides instant change from reception to transmission and is suitable for operation by personnel of liri1ited radio experience. c. UsE. The equipment is designed to operate either as a field

18、tation or a vehicular radio, provid- ing radio-telephone and continuous-wave ( c-w) communication to antiaircraft brigades and regi- ments. d. TRANSMISSION AND RECEPTJON. ( 1) The transmitter sends voice-modulated and continuous- wave symbols. (2) The superheterodyne receiver detects both voice-modu

19、lated and tone-modulated c-w telcgrap;l signals. e. DISTANCE RANGE. Communications may be carried on over distances from 20 to 30 miles when the unit is operated as a field station. As a vehicu- lar radio (vehicles in motion ) , the range is approxi- mately 15 miles. Actual distances vary according

20、to conditions of weather, height. location, or operat- ing frequencies. f. FREQUENCY CovERAGE. The .frequency range is from 1,680 kilocycles (kc) to 4,450 kc. g. CHANNELS. Six crystal-controlled frequencies within the operating range may be preset, and in stantly selected for both reception and tran

21、smission. Manual control of the receiver is also provided. ( 1) The frequencies supplied with the unit arc as follows: Channel Transmitter Receiver crystal frequency crystal frequency 1 . 1,746 kc. 2,131 kc. 2 . . 2,082 kc. 2,467 kc. 3 0 2,280 kc. 2,665 kc. 4 0 2,340 kc. 2,725 kc. 5 . . 3,442.5 kc.

22、3,807.5 kc. 6 . . . . . . . . . . . 4,255 kc . 3,870 kc . (2) To permit instant change-over from trans- mitter cry. tal operation to receiver crystal operation, the receiver-oscillator crystal frequencies differ from the corresponding transmitter crystal frequencies by 385 kc, the receiver intermedi

23、ate frequency (if). On channels , 2, 3, 4, and 5 the receiver-oscillator crystal frequencies are 385 kc higher than. the trans- mitter frequencies in the same channels. On chan- nel 6 the receiver-oscillator crystal frequency is 385 kc lower than the transmitter frequency. h. PowER. ( 1) l11jmt. The

24、 alternating-current (a-c) power drain is 220 watts while receiving and 550 watts while transmitting. Standby operation of the receiver is possi.ble when Power Unit PE- l 08-(*) is used with the receiver-transmitter. Re- ceiver input power is obtained from a 12-volt storage battery in the power unit

25、. Receiver fila- ment voltage is obtained from the battery directly. Receiver plate voltage is obtained indirectly through the vibra-pack section of Power Supply Unit PE- 110-(*). Direct-current (d-e) power drain is 5.5 amperes. (2) Output. The transmitter has a nominal out- put rating of 45 watts.

26、i. CoNSTlWCTlON. The receiver and transmitter are housed in a two-section steel cabinet (fig. 1), which in turn is shock-mounted in a wooden chest. The upper deck of the steel cabinet serves as a chassis for the radio-frequency ( r-f) components of the receiver and transmitter. The lower deck serves

27、 as a chassi for the modulator of the transmitter and the audio output of the receiver. Cpper and lower sections are fastened together by snap latches. They are held to the wooden chest by snap latches. ( 1) Receiver. The receiver section of BC- 669-( *) (fig. 2) is a seven-tube, superheterodyne cir

28、cuit operating in two frequency bands and six crystal-controlled channels. (See schematic dia- grams, figs. 54 and 53.) Crystal or manual control is available in either band. Reception is either hand- set, headset, or loudspeaker. By using the static filter switch provided, 1 ,000-cycle code signals

29、 can be received. This switch when ON operates a peak limiter and 1,000-cycle tuned circuit. These effec- tively reduce static and electrical disturbances. Also a beat-frequency oscillator (bfo) is included for c-w telegraph reception. Operate CW-OSC SiVITCH- See TM 11- 625 for installation, operati

30、on, and other maintenance data on this equipment. - V8- V9- PLATE TANK- COIL L3 ANTENNA LOADING COIL L4 CAPACITOR C44 -LI .-V2 T4 T3 T8 Tl ANTENNA POST TLI9680 Fi.r;nre 2. Radio R rCPiver and Trans111ill!r /J -669-(*)- /ofJ ztirw, 1- chassis. Sll for CW reception. Antenna relay RYl switches from rec

31、eption to transmission. (2) Tmnsm:itter. The transmitter section (fig. 2) is a crystal-controlled voice emission unit. It uses an oscillator tu.be J AN-6L6 and two r-f power- amplifier (p-a) tubes. The antenna coupling is controlled by frequency channel switches corre- sponding to selected frequenci

32、es. The antenna cur- rent is 1 to 1.5 amps. (See figs. 54 and 55.) ( 3) M odulato1. The modulator section c nsisb of a driver Tube JAN-12J3GT (VT-115-A). These tubes operate in push-pull parallel as a class ABI, audio-frequency (a-f) power amplifier. (See figs. 3, 48, and 49.) The modulator section

33、con- tains a switching arrangement for changing from modulation to telegraph tran. mi sion. Switching is effected through switch S14. A o jacks are pro- vided for plugging in KEY, PHONES, MIC into jacks Jl, 2, and J3 respectively. ( 4) lVI eters. An antenna current meter and 1 d-e milliamcter or rea

34、ding power-amplifier plate, mnduhtor plate, and a p-a o-riel CUlT nt arc: pro- vided. (Sec fig. 1.) 2. Over-all System Function a. lECEIVEil SECTION. (1) l?adiojrequeucy am- jJ/ificntiou stage. 1.-f amplifier Tub.e JAN-6S.K7 (V1) amplifies signal voltages at racl1 o ft:equenc1 es, a11d, together wit

35、h sharply tuned CllCUJts of r-f I ra11sformers Tl or T2. greally attenuates signals of undesired frequency. Signal voltages picked up by I he :111tenna appear across the primary of the first r-f transformer. Through tuned parallel resonant circuit the sign:1l voltage is fed to the control grid of th

36、$ IIIli! ttOO 01o4HP sc-ss9-c. 400 OIIYS 1.0,000 011)$ 10.000 Q!lot$ 125 05 1.000 QlfV$ 500 OHotS 100.000 0115 lUliNG 200 V0C11 iiOOVQCw sao voco 600 VO(W r.ooo voc . t.OOO V(ol 100 vocv 1.000 Q(ot 100 Q(o ,QQ VQ(o 25 VO( 00 OC- RlliiiG . 2 . 2 . 2. t.tz v 2 . . 1/Z w l/2io 1/ 2 w 1/211 1/2 w 1/ Z I

37、i 1/Z v 1/2 w 300 IotA 300 IotA ;o ;o 20 o( 10. 10. ,. 1211 Pt.t.TE POWER PL z u v,:; .ll v, v,z ( 0-=-0 1 roo + Olt.lf . on LMz jAECEWEA/ :&;_ : I .-t- I t I I CA, IOI I I 500 Mf =!= I - I 1 6666661 I !J 7 9 II PL.1 z .; 6 8 10 12 ? . ? i ? ? ? - _qn _j :n I II I I =o=_jl_ .Jl n v-fROT Sll -:- jPHQ

38、,jSj IOIC(-Cwl r- -:-SWITCH t C.o.-:0:=-=0=-=-0-:0_-;:0- = -=-=-=-=-=-=; -=-=-=-=; h_ _ - -=-220M -=-r 1 7 - c,oz-+-4-, -=-SlOE TOE OSC ., . AND SFCH AMPLR J:Orl-6l6G T 2,000J p v, : ,., I A!J2 lOOn P 0 I) I I I LS, I I I ., Z!JOlot -A.A. A son . , s 0 lSIJl . 8; =r I I I . ,o -;-I,OOOn I ;M _f,CrtM

39、f, )-. 9F I :r. s, 7 !TR.:OI.SMITT(I:t 1W!TC I Rb6 EOU.O.LS 400-.Jl. IN BC -669-C. M I,OOO .!l I :;: t S SYWSOl FOR Fl.tEO CAPACITOR POSITION 1 - J.,OO.PL.t.r C.UAR(NT POSITION l -PA PLt.Tt! CURRENT POSITION- CURPE! F-igure 6. Rad-io Receiver and T1-a11smitters BC-669-A, -B, a11d -C, 111oduJator sec

40、tio11, u.rith modificatioH for c-. operatio11. . PL2 TO 00NE.=? SJ PPLY L: T PE-nr-:J v., 7( V15 Vt:; V14 V1 2 2 2 4.000 - -:._-_-_-_-.=-=:_-=-=-=-=50 II I 1 12 II a t so, SITCH I -r-r :1 I TRANSMITTER J rf-J . POWER l9lo- S14 4 rr:-= - I II , 1 0 St4.8 r=- 191 :-;,0-VL:-Ell 0 b -1 ,R59 50!1-. PeG F

41、 I OMEG 0.02M . 19lC-240 M -:-:- - R1o N I _. j c72 GQfIF G 0.53081l R61 V1 50!1 v 1 R64 2! o.530enl !z -._ _:_ _ .:_ 3 55.1 55 2 + - 2 DIRECT CURRENTl Figure 7. Radio R eccive r a11l Tra11smitter BC-fJ69-D, modulator sectiou, schematic. f METER 551 55 2 POSI TION I CURRENT POSITION 2 lPA GRID l CUR

42、RENT POSITION 3-lMOD PLATE CJRRENT TL 167648 (30) The following miscellaneous parts have been changed : RY1 S3 T1 T2 T3 T4 T7 T8 T9 Vl 12 V3 oV4 vs V7 18 V9 VJO b. The changes mad on Radio Receiver and Transmitter BC-669-B on some equipment pro- duce I on Signal Corps Order No. Li536-I hila-43 arc a

43、s follows : (1) Base clamps have been added to tubes VlO, 112, V13, Vl4, VIS. (2) Tube-holder a sembly bas been added to tubes V8, and V9. ( 3) Crystal clamps have been added. ( 4) Steel strap has been a ldccl around capacitors C68, C69, and C71. ( 5) Clamp has been added to hold cover of relay R Y2

44、 in place. c. Di fferenccs bet ween BC 69-B and B -669-C include changes made on Radio Receiver and T rans. mitter .BC- 669- on Signal Corps Orders Nos. -l791-Phila-43 and 15537- Phila-43 as follows : ( 1) Capacitor C6 is connected between R3 and US. (2) Allcnh ad type setscre11 not used. ( 3) htse

45、holders remain olcl type. ( 4) Allen set crew wrenches arc not used. (5) Knobs on the front pa1 iel differ in style. d. The changes made on Radio Receiver aud Transmitter BC-669-C on som sets produced on Signal Corps Orders No. . 4791-Phila-1-3 and 15537-Phila-43 ar as follows : ( 1) Trunk fasteners mounting BC- 669-C n the mounting pen have b en changed to drawbolt clamps. (2) The cover of relay R Yl is bcld in place by a set