Scott-325R-335R-Service-Manual 电路图 维修手册.pdf

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1、SCOTT 325R/335R FM IF Amplifier To pin 11 of!C301 0 Shei/ded L2 Coax Cable 0 3 turn coil 0 0 0 To chassis ground I) Mute the FM local oscillator by shorting IA. 2) Connect the oscilloscope to pin 11 of IC301. 3) Apply 10.7 MHz signal from the sweep generator to L2 in the manner as shown above. 4) Ad

2、just L201 for correct figure as shown. It may be neces- sary to increase or decrease the sweep generator output for adjustment convenience. FM RF Tracking -I 1S446, etc. , 470k ohm I I I I I I _ .,_. _ .,I -.J Correcc 111 ffJ Oa FM Dummy Ant .-,Tape/Rec 2J Out FM Signal Generator o:.=i FM Ant 300Ohm

3、 I) Apply 90 MHz, I kHz and I 00% modulated, 25 dBf signal level to the FM antenna terminals. 2) Tune the unit to 90 MHz. 3) Observe the oscilloscope connected to the Tape/Rec output terminal for symmetrical sine wave. If failed, adjust IA. 4) Adjust LI and L2 for maximum level meter reading. Re- du

4、ce input from the 25 dBf level as necessary to maintain noise on sine wave. 5) Readjust the signal generator for I 06 MHz, and retune unit. 6) Repeat step 3. If failed, adjust the OSC. trimming capacitor mounted on the tuning capacitor. 7) Adjust the trimming capacitors, for mixer and RF. 8) Repeat

5、as necessary until product specifications are met. Level Meter DJ Distortion Analyzer 0.001F Oscilloscope Incorrect, as coo low Oscilloscope lncorrecc, as too narrow RadioFans.CN 收音机爱 好者资料库 Center Tuning Indicator (LED Pointer Assy.) Connect DMM (switched to DC volts) between chassis and pin 15 of I

6、C20 I. Tune receiver to signal generator with output level set at 65 d Bf. Carefully tune for lowest AGC voltage (approx. 2.5). FM Distortion With unit connected as above for tuning indicator adjustment, adjust T203 for minimum harmonic distortion. FM Signal Strength Display 1) At 98 MHz, with recei

7、ver connected and tuned to FM gen- erator, apply 65 dBf signal to unit antenna. 2) Adjust R217 until all five LEDs are lighted. Mute Threshold Adjust 1) At 98 MHz, 20 dBf signal level, and set-up connected as above, tune unit with mute switch in the OFF position. Multiplex Pilot Adjust 1) Apply 98 M

8、Hz, 65 dBf signal to the unit with no modula- tion. Stereo Separation I) Apply 98 MHz, 65 dBfleft channel signal to the unit modu- lated with 1 kHz, 9% pilot signal. 2) Connect a digital voltmeter to the right channel Tape/Rec output terminal. 3) Adjust R3 l 5 for minimum leakage (minimum level) on

9、the voltmeter. AM IF Amplifier I) Apply 455 kHz sweep generator output to the unit AM antenna terminal. 2) Connect scope to pin number 12 of 1C3. 3) Adjust T8 to obtain maximum and symmetrical display as shown. AM Tracking 1) Apply 600 kHz, 30% modulated with 1 kHz to the AM bar antenna. See test se

10、tup figure. (Distance between the AM bar antenna and emitting loop antenna should be 2 feet.) 2) Adjust signal generator output so that a sine wave appears on the scope. Reconnect DMM to terminals 603 and 604 on display board 3014-513-8108. Adjust T202 for zero volts on DMM. Since there is some inte

11、raction between coil settings repeat center-tune and distortion adjustments for optimum results. 3) Reduce RF generator output to minimum, tune receiver off station and adjust R621 on display board until both green LEDs in pointer assembly are turned ON and all signal strength LEDs are turned OFF. N

12、OTE: R2 I 7 replaced with fixed resistor in some produc- tion units. 2) Switch MUTE ON and adjust R220 until FM output is muted. 2) Adjust R317 for 76 kHz reading on the frequency counter connected between TP and chassis ground. A deviation of +200 Hz is acceptable. 4) Apply 98 MHz, 65 dBf right cha

13、nnel signal to the unit mod- ulated same as step 1. 5) Move digital voltmeter to the left channel Tape/Rec output terminal. 6) Check for approximately the same leakage as in step 3. 3) Adjust Ll02 for maximum audio output on the digital volt- meter connected parallel with the sCORe. When turninp: co

14、re, always adjust signal generator output to maintain low input level. Do not change voltmeter range. Moreover, al- ways keep the generator output as low as possible to avoid RadioFans.CN 收音机爱 好者资料库 SCOTT 325R/335R :i BAR ANT AM Signal Generator Radiat1011 600kHz/ 1 400kHz Loop AGC action and to kee

15、p the measurements accurate. 4) Adjust the AM loopstick antenna core for maximum output reading on the voltmeter. 5) Shift generator frequency to 1,400 kHz with same modula- tion condition. 6) Repeat step 2. Audio Adjustments uJ s Tape/Rec Out - r:. :. -= Level Meter Oscilloscope 7) Adjust OSC. trim

16、mer for maximum voltmeter reading. 8) Adjust Ant. trimmer for maximum reading on the volt- meter. 9) Repeat items 3 through 8 for best tracking and maximum sensitivity. Equipment Required Audio signal generator. Digital multimeter. Speaker load resistors, 8 ohm 100 watt. The following adjustments ar

17、e the same for both the left and right channels. Bias Adjustment 1) Connect 8 ohm load resistors to the Speaker A terminals, and set the Speaker A switch to ON position. 2) Turn the Volume control fully counterclockwise. 3) Turn Rl412 fully counterclockwise. 4) Using digital multimeter set meter to

18、read 200 mV. Connect probes across Rl423 and Rl424 (Voltmeter bias test points, L channel). Turn unit ON. Let it idle for at least one minute. Adjust Rl412 for 20 mV across the resistors. Power Indicator Adjust 1) With 8 ohm speaker loads connected, increase output until 15.5V are measured across ou

19、tput loads. Dial Cord Stringing 1) Loosen the screw securing the drum to the variable capa- citor shaft. 2) Tie the end of the cord A as shown to the fixing pro- trusion on the drum. 3) Wind the cord.two turns around the drum then thread it through the rollers, etc., following the illustration. 4) T

20、ie the end of the cord to the coiled spring so that the proper tension of the dial cord is obtained. 5) Align the pointer position for the correct frequency indica- tion on the tuning dial. 6) Secure the screw on the drum. 5) Perform the same procedure for the right channel, except measure voltage a

21、cross Rl473 and Rl474 (voltmeter bias test). Adjustment is made with RJ462. 6) Leave the amplifier on for about 30 minutes, then rechec measurement. A tolerance of 25% is acceptable. Readjust if necessary. 2) Adjust R803 and R853 until all green LEDs are ON. 3) Increase output level and note red LED

22、s switch ON. (ff RadioFans.CN 收音机爱 好者资料库 ,., !/% . ,r, -=-m,: ,rtf.r,i. ffif.1ir!,Ei11:j ;!; . gJg+saTJ 0T0T0TR c,11 .i.l/ffil 0 -ft . :,J,JffillVl, .,_ . .,. C d l c :, ;.-ti-c -.J./ 1 -i . . .1. u f. 0 Gu 1.T . R4c 5 : _- T -* A415 . . , I T _, . : ! l . . i d-*. m J.f :i. m ! .I. )I C . 1 I : T :

23、 t: T ,-IVt/,-, -T t j T - - u v / f 1 : I-f I -k . / 1 L .f o .LJ 1.r . T :f ; -:c : : l- 0 N N coo cirn1; SCOTT 325R/335R Symbol/ Exp. View No. Description Specification Part No. Used In Power transformer 117V 2869-177-6103 335R Power transformer 117V 2869-192-0100 325R Tuning shaft . 5104-506-510

24、1 both Aux jack PC-8 input 3334-500-8107 both Wheel, drum Tuning cap drum 5224-501-1109 both Spring, dial . 6674-501-9107 both Screw Top cover mtg. 7128-540-2032 both Washer Top cover mtg. 7734-500-1106 both Side cabinet, R . 6103-500-1107 both Side cabinet, L . 6103-500-2102 both Volume knob - 7724

25、-505-7108 both Rotary knob Tone/selector 7724-505-6103 both Balance knob Plastic 7724-506-0106 both Front panel w/o window 7702-507-1207 335R Front panel w/o window 7702-507-1100 325R Back plate, volume . 7714-504-7100 both Window, dial Plastic 7653-502-5104 both Pully, guide - 5264-501-3104 both Pu

26、lly, guide . 5214-501-3104 both Bolt, decoration . 7734-500-3205 both Bracket, guide pointer . 6613-504-7109 both Cap - pointer 94HB ABS 8003-500-3106 both Scale, dial 0.8 AL 8012-503-6108 both Bracket, ant bar . 6614-117-3100 both Coil, ant bar 2509-305-1016 both Terminal board, push Spkr 3304-501-

27、6105 both Jack, AC outlet 125V, I SA SI 6444 3334-500-1005 both Switch, push ESB 70274T spst 3529-102-0200 both Foot Rubber, black 6074-500-2101 both Cabinet, top I .OT vinyl on steel 6102-502-5106 both Guide, knob PE Soft Natural 6463-500-1106 both Knob, tuning ALB 7724-505-5108 both Varicon, air C

28、-752-J 1809-317-0201 both Jack, earphone HU0190-0l-020 3P 3333-101-7102 both Switch, push SUF33 2C2P 3529-203-0406 both Hl2.Sx 2/Hl8 Potentiometer GM70E20FM7Cl OOK 1269-111-1309 both Potentiometer FJ60E25FMI IW250K 1299-102-0 I 07 both BIOOK Switch, push SUF43 H= 18mm 3529-203-0503 both -SW! Switch,

29、 rotary, slide HRW0332-0l-250 3509-101-0207 both 4C4P Knob, mould balance ABS black 8414-500-3100 both (C503,504) Capacitor, elect 35V 6800M-PCB !619-018-2400 both Dial cord 0729-I40-2016 both Terminal board, screw 4Tscrew 3304-101-5201 both Guide, knob P ABS grey 6464-501-5106 both Spring, push kno

30、b P STS #27 Pl0.4 6674-506-5102 both Knob,push P 94HB ABS 7724-505-8103 both Guide, knob F 94HB ABS Sanding 6463-500-7106 both Transistors Symbol/ Exp. View No. Description Specification Part No. Used In Q501 FET 3SK45 2139-601-4602 both Q502, 503 Transistor, bipolar KSC1674-0 2139-301-0508 both Q20

31、1 Transistor, bipolar KSC838-0 2139-301-5808 both Q301,503, 1407, Transistor, bipolar KSC945-Y 2139-302-7 409 both 1457,601,602 Q801,851 Transistor, bipolar KSC945-Y 2139-302-7409 335R Q603, 604,605, Transistor, bipolar KSA733-Y 2139-301-3802 both 1408, 1458 Q302,352 Transistor, bipolar KSA539-Y 213

32、9-103-2904 both QSOI Transistor, bipolar KSD288-0 2149-401-2609 both QS02, 504, Transistor, bipolar KSA708-Y 2139-103-7103 both 1403,1405, 1410, 1453, 1455, 1460 QI401, 1402, Transistor, bipolar KTC-2440-BL 2139-305-6704 both 1451,1452 QI409, 1459 Transistor, bipolar KSC-1008-Y 2149-301-4309 both Ql

33、411, 1461 Transistor, output TIP-41B 2149-305-1102 325R Q412,1462 Transistor, output TIP-42B 2I49-201-9606 325R QI411, 1461 *Transistor, output 2SCI827 2149-301-710 325R Ql412,1462 *Transistor, output 2SA769Y 2149-101-430 325R Ql41 I, 1461 Transistor, output 2SC2577-Y 2149-401-3206 335R Ql412, 1462

34、Transistor, output 2SA1102-Y 2149-201-0106 335R NOTE! *Used in 325R witn SN 11050001 and up. Diodes CR201, 202, Diode, switching ISS53 2169-301-2901 325R 203,301, 502, 335R 503,1401,1404 1405, 1408, 1451 1454, 1455,204 1458,605 CR804, 854, Diode, switching 1SS53 2169-301-2901 335R 805,855,806, 856,8

35、07,857, 808,858 CRS0S, 506 Diode, zener 1214 2169-404-1700 325R CRS0S, 506 Diode, zener RD18E 2169-403-2207 335R CR504, 1402 Diode, zener RDl2E 2169-403-1105 335R CR507, 508, Diode, rectifier INS 173 -300V, 2A 2169-201-1305 both 509,510 CRSll, 512 Diode, rectifier IN4001 -SOY, I A 2169-201-0504 both

36、 CRl406, 1407, Diode, rectifier IN4003 - 200V, I A 2169-201-0708 both 1456, 1457 CR1403, 1453 Varistor STV-3H 2189-105-1007 both CR601 LED -meter LN-05202P 2309-117-0102 both CR302, 801, LED -square LN217RP 2309-120-0 I 02 both 851,604 CR802, 852 LED -meter LN5302PGRN 2309-119-0205 335R CR803, 853 L

37、ED -square LN317 GP 2309-ll9-0108 335R CR602, 603 LED -stereo LD57AGRN SPI 2309-101-7506 both SCHEMATIC DIAGRAM 335R :, i h ._ 3 , .i 335R 7 ! C g 0 I :t HJ4a I ;!,:,: . ,_,1-. . -+c .-:. 11Ma . SWITCMU SWI VNCTIO 1AM ,1111 flHONO AUX) SW1 UP( tSOUlICC MOHITOIU f1r,I MUT 10N 01 SW4 . 00 l STllttO UO

38、Jt() SWO LOIJONCSS (O ON I TltNGISTOR t.AYO.JT ( LAO N O Vl(W) 02 o, 0201 0)01 0502 0352 050:2 o,o, OIOI 0,02 OM)J 0,01 01401 014$1 0!402 014!U Oi.tOS 011 0 140 1 0 1407 01408 014!18 01401il 0109 0410 01460 SW IISOHIC rit.T R (Of f -.)NI $W 7 SPAICR A (00 -Of11 swe SP,UR 8 IOFF OH I SWlil POM R IQff

39、 -Olroll . 0,0, . 01411 0141 014 12 01462 HT LAY()JT (.C.4.0 ENO VlWl OJ-2 ,i, o, TOP VlWlf IC 10 1, IC201 IC.-:+.= . H iI 4 . =-+-! . SGNAL INPuT, LOUOftUS SWlftH fol or,; POS!TIOfil. UN( -Ol,.TAG( 120v USING SCHEMATIC DIAGRAM 335R :, WO 0. . 2 . Q:,1-1 335R (l:iOt 0 . , 0 CtOt 111101: 41/11 tO - S

40、WITCHS OJ Ci674 0 . 01 3 SK 45 1111 . ., en, o 01 5WI TVftrfCTION lAII lM PHOHO AUX) SW 2 TA SOIAIC( MON!TOII J SYtS FM MUT tON -on) SW4 . 00( ( ST(Jlt(O MONO) SWO LOVONfSS CO,., OH) TRANSISTOR t.AY(l.JT (LEAO ( NO Vtf:Wl E e o;z o, 020t 0301 0302 03,2 0502 0503 - 02 C674 0 I ,v S W J l 10 . T IOt -

41、 c,10, = 0201 C88 0 IJV ,oo, 0301 C9 45 Y N N 0 0 -0 r-f-OS . 21 I (;401 IU(lt 4 r II lQOr ,-!._ . , ,oo, 0 CtlI ,so - SW6 SW7 swe 9.J8S0NIC SPEAiER SPEA,.J-.!.I Al. I 0 i u I (Off-NI (OFF-ONJ tOFfON ) (Off -ON) 11 ,. ii V 8 C E 401 ILi 0 s . ., ,oo f - FET LAYCX.JT 01 TOP VIE W IN0X MARtc IC201 .LJ

42、. = = 0302 CJl4 A39 Y o.OOf.:2 CH4 0352 Ooo A!i39 Y I ClOI 4.11 ,. c, If, 10011 . . C202 ISS6S - c10 Of,- - _.,ffI -, 0 . . . ., 0 Oil - 0 060 1 C4:, - . . COM 1 J $WI SW2 SW3 SWA SW5 UNCTION (AM ,M , ,.OHO AUX) TAPt: 111 MUTE 1 OH -o,.r MOO Rt7 IOOlt .,_ ltt09 . . . co1 . ., .!Jo 100 K . - swe SW7

43、swa SWII 1101 VIEW I C Q,OC 01411 01461 01412 01462 s.i,soHIC SPf:AKER !PAK(R P0W1: FILTER A a (OFF-ON) (Off ON) (OFF ON) (Off ONI SCOTT 325R/335R - ._ . , . CZ tt , ear . 11 REVISIONS 32SR Output transistor change: Serial No. 11050001 and up. QJ41 l, 1461 from tip 41B to KSC 18274 Ql412, 1462 from

44、tip 42B to KSA 769-4. ir . oan _. (o; J ) )I( (; 407 0 I H._ :ix Ht- C4S7 0 I - fET LAYOUT (LEAD ENO VIEW) o -G2 $ - -0 1 0 I TOP VlW INDEX MARJ IC 101, IC201 1 C60 1 I 0 ., . L .J . -, .J. C40 . 0 011 i 04()1 14 II II I IO t o o a ._,_L., INQEX MARK IC 301 X 7-0 ,-+-f-f-+-1-j.-):,:D:,:l:_:L:_:t_:rr

45、:_:. ;, , - ceo1 11$0 JI-+ -11-. , 01 X - ,c 404 IC90C ,. . a7K 4, ?IC y ! I I 325R Pt. No. 2869-192-0100 2869-192-040 2869-192-050 32SR -33SR 335R Pt. No. 2869-177-6103 2869-177-640 2869-177-650 Com1nencing with serial number 1 I 030001 both models have a primary fuse installed, the fuse is mounted

46、 in an in-line fuse holder accessible only after top cover removal. 325R uses a 2A 250V fuse, 335R uses a 3A 250V fuse. 325R-335R Resistors, Rl414 and Rl464 in the output bias circuit changed from 4.7K to 3.9K. - -o t 409 c 1ooev T . 0 1460 A 708 Y NOTE TIP428 - - x J ,I I . ./ NOTICE: MANY OF THE T

47、RANSISTORS USED IN THIS CIRCUIT ARE IDENTIFIED BY A K PREFIX IN PLACE OF THE MORE FAM I LIAR 2. WHEN IT IS NECESSARY TO REPLACE DEVICES THE 2 SERIES MAY BE USED HOWEVER SERVICE PERSONNEL MUST OBSERVE PROPER LEAD CONNECTIONS. - 11114,lf tfO IW - v 110 , . . . ., l All Rt:SISTANc:E VALUES IN OHM KIRW1SE HOTEO IN SCHCMTIC ALL CAPACITORS IN MfO PF: PICOfAltAO, 3 , THR MIOHT l!I( SLIGHT CHNIIES IN THC ACTUAi. SET. 4 ALL LTAGES Alli