Nikko-Gamma5-tun-sm 维修电路原理图.pdf

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1、ALIGNMENTTEST EQUIPMENTAllow a minimum of 10 minutes warm-up for test equip-ment and the tuner to be tested.Maintain rated line voltage.FM Signal Generator (FM SG)OscillascopeAC VoltmeterDistortion MeterMPX Signal Generator (MPX SG)Frequency CounterAM Sweep Generator (AM SG)DC VoltmeterFM SECTION5.1

2、2 MHz ADJ; 76 kHz ADJIMPX SIGNAL GENERATORIOUTPUTI1GENERAL ALIGNMENTAlways observe responsealignment procedure:INSTRUCTIONcurve on oscilloscope during1.Do not apply signal from FM or AM stations.Apply signal from generator only.2. Use of excessive signal from FM SG or AM SG cancause overloading of t

3、he tuner circuits. To properlyalign the tuner, adjust FM SG or AM SG outputlevel control so that response curve on oscilloscope isnot distorted.FM SIGNAL GENERATORSTANDARDDUMMYGAMMA VL-_IZEXT MOD INPUT_ -_ - - _TO FM ANTENNA TERMINALSTO OUTPUT TRERMINAl_SFigure 6. Test Equipment Hook-upFREQUENCY SYN

4、THESIS TUNER SECTIONFM Front End AdjustmentThis adjustment is factory preset and should not need readjustment.5.12 MHz Crystal Controlled Oscillator Adjustment.Set MAIN POWER switch (Sl I to ON position and POWER switch (S2) to OFF position.Connect frequency counter to test point “TP 1” (Photo 7).Adjust C917 (Photo 7) for 5.12 MHz * 20 Hz.1 DISTORTION 1AC VOLT-METERL-J_ _- _-INPUTIOSCILLOSCOPE1-TF5- TF4- TP5-R316- R315-TPl5-TP4$-c917Photo 7. Adjustment PointsRadioFans.CN 收音机爱 好者资料库RadioFans.CN 收音机爱 好者资料库