GrundigSonoclock755 维修电路图、原理图.pdf

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1、nderungen vorbehalten Subject to alteration sonoclock 755 Es gelten die Vorschriften und Sicherheitshinweise gem dem Service Manual Sicherheit, Sach-Nummer 72010-800.00, sowie zustzlich die eventuell abweichenden, landesspezifischen Vorschriften! The regulations and safety instructions shall be vali

2、d as provided by the Safety Service Manual, part number 72010-800.00, as well as the respective national deviations! 72011 049 5200 (0498) Druckplattenabbildungen / Illustration of Printed Boards Bestckungsseite / Component side nderungen vorbehalten Subject to alteration sonoclock 755 72011 049 520

3、0 (0498) sonoclock 755 Verdrahtungsplan Wiring Diagram nderungen vorbehalten Subject to alteration 72011 049 5200 (0498) FM RF ALIGNMENT STEP SIGNAL SOURCE (FM Signal Gen.) CONNECT TO SET SIGNAL TO ALIGNMENT INDICATOR (Oscilloscope, VTVM) CONNECT TO SET RADIO DIAL TO ADJUST ADJUST FOR REMARKS L104 (

4、Osc. coil) 187.35 MHz(Lowest end)stretch or (modulated)squeeze TP ( 1 ) & ( 2 )108.25 MHzTerminalsVCT1 BVolume 2through matching network(modulated)across speaker (Highest end)(Osc. trimmer)Maximumcontrol at if necessaryvoice coilL103 (RF coil)max. position 388 MHz88 MHzstretch or (modulated)squeeze

5、106 MHzVCT1 A 4(modulated)106 MHz (RF trimmer) 5 Repeat steps 3 and 4 as necessary to minimize tracking error and also steps 1 and 2 if necessary AM RF ALIGNMENT STEP SIGNAL SOURCE (AM Signal Gen.) CONNECT TO SET SIGNAL TO ALIGNMENT INDICATOR (Oscilloscope, VTVM) CONNECT TO SET RADIO DIAL TO ADJUST

6、ADJUST FOR REMARKS 515 KHzL105 1(modulated)(Lowest end)(Osc. coil) 1630 KHzVCT1 CVolume 2A standard radiation(modulated)Across speaker(Highest end)(Osc. trimmer)Maximumcontrol at loop ant.588 KHzvoice coilL102max. position 3(modulated)558 KHz(ant. coil) 1440 KHzVCT1 D 4(modulated)1440 KHz(ant. trimm

7、er) 5 Repeat steps 3 and 4 as necessary to minimize tracking error and also steps 1 and 2 if necessary CLOCK FREQUENCY ALIGNMENT SIGNAL SOURCE CONNECT TO SET SIGNAL TO ALIGNMENT INDICATOR (Frequency Counter) CONNECT TO SET RADIO DIAL TO ADJUSTADJUST FORREMARKS No signalTP ( 5 ) and TP ( 6 ) with 10

8、: 1 test probe Through Any4.194304 a cap. 1 pF to 3 pF. ( It depends on the sensitivity of PointTrimmer 200 Mhz the frequency counter ) A L I G N M E N T P R O C E D U R E MODEL NO. : SC-755 INSTRUMENTS REQUIREDGENERAL PREPARATION 1. Signal Generator1. Check source voltage, DC or AC according to spe

9、cifications 2. FM Signal Generator2. Set function switch to band being aligned 3. Sweep Generator (10.7 MHz for FM)3. Signal input should be kept as low as possible to avoid AGC and AFC function 4. VTVM4. Standard modulation : AM 1 KHz 30% mod 5. OscilloscopeFM 1 KHz 22.5 KHz dev 6. Frequency counte

10、r 7. Regulated DC power supply AM IF ALIGNMENT STEP SIGNAL SOURCE (AM RF Gen.) CONNECT TO SET SIGNAL TO ALIGNMENT INDICATOR (Oscilloscope, VTVM) CONNECT TO SET RADIO DIAL TO ADJUSTADJUST FORREMARKS A standard radiationTP ( 4 ) Detector output terminalQuietVolume control at 1loop465 KHzand groundPoin

11、tT102Maximummin. position 2 Repeat step 1 for max. output FM IF ALIGNMENT This model requires no FM IF alignment as the IF is fixed by ceramic filter and discriminator CF1 & CF2. Please take note that correct type and same color dot of ceramic filter is used in servicing, diff color dot of ceramic filter may cause worse IF S curve characteristic and distortion. Connect IF genescope output terminal to TP3 & TP2 (GND), connect scope input terminal to TP4 & TP2 (GND), then the IF characteristic curve can be observed. nderungen vorbehalten Subject to alteration 72011 049 5200 (0498)