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JVC R-X40 Service Manual
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Ltotrf\--l cto2@r:\Lr02o Tr ro Tlotsw305 sw507 sw306sw302 sw304 sw3055. Adiustment Procedures5-(1) FM/AM (MW/LW) Tuner Adjustment Procedures\-\-\,Fig.8FM SectionBand Cover1. Set the frequency display to 108.0 MHz.2. Connect a DC. VTVM. to test points 117 and GND.3. Adjust Ll03 so that the VTVM. shows 8.00V.4. And set the frequency display to 87.5 MHz.5. Check the VTVM. voltage reading 1.60 V t 0.5 V.Note: After adjustment, confirm that the band cover isas follows: (for West Germany only)FM: Low-end 87.5 MHz - 300 kHzHish-end 108.0 MHz +500 kHzSensitivityLow Frequency1. Connect an RF generator to the antenna terminals onthe rear panel through a dummy antenna.2. Set an RF generator to 90 MHz, a modulation of 1 kHzand a deviation of 75 kHz to provide an input of 2 1tY.3. Connect a VTVM and an oscilloscope to the Rec. outjacks on the rear panel.4. Set the frequency display to 90 MHz.5. Adjust coils L101 , L1O2 to maximize the output.High Frequency6. Set the RF generator to 106 MHz, a modulation of1 kHz and a deviation of 75 kHz to provide an inputot 2 1tY.7. Set the Frequency Display to 106 MHz.8. Adjust the FM trimmers C102 to maximize the output.9. Repeat these high and low frequencies adjustmentalternately until maximum sensitivity is obtained.Descriminator, Distortion and Signal Gain1. Press to FM position.2. Connect an RF generator, 1 kHz modulation and a75 kHz deviation to the antenna terminals on the rearpanel through a dummy antenna.3. Connect an oscilloscope, Distortion Meter and VTVMto the Rec. out jacks on the rear panel.4. Set the RF generator to 98 MHz, generator output tominimize.5. Set the Frequency Display to a 98 MHz.6. Connect a DC VTVM between TP1 1 1 and 1 12.7. Adjust the core indicated arrow A of T101 for DCVTVM reading of 0 (zero) mV.8. And set the RF generator output to 1 mV.9. Adjust the core indicated arrow B of T101 so thatthedistortion is minimized.Multiplex and Stereo SeparationMultiplex1. Set the stereo signal generator as follows: 400 Hzmodulation frequency, 7.5 kHz deviation pilot,67.5 kHz main and sub carriers. Connect its output tothe RF generator.2. Connect an RF generator to the antenna terminalsthrough a dummy antenna.3. Connect a VTVM, an oscilloscope and a distortionmeter to the Rec. out jacks on the rear panel.4. Set the RF generator to 98 MHz and outputof 1 mV.5. Set the frequency display to 98 MHz.6. Connect the frequency counter to 19 kHz Test PointTP1 08.7. Switch off the pilot signal of stereo modulator.8. Adjust R181 so that the frequency counter indicates19 kHz (0 - -50 Hz).Stereo Separation9. Switch the selector of stereo modulator to left channelmodulation.10. Adjust R173 so that the output ofminimized.1 1. Switch the selector of the modulatormodulation.right channel isto right channel12. Adjust R173 so that the left channel is minimized.13. Set R173 to a average, if the separation of left andright is different.Stereo threshold14. Adjust R143 so that STEREO indicator lights at theoutput of RF generator 10 pV.\-R.X4O / R-X4OLNo.2603\- |
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