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GRUNDIG Service
CIRFLEXX UMS 4201 SPCD
Adjustment Procedures
Tuner
Test equipment: Sweep / Signal Generator, Distortion Meter, Oscilloscope, Digital Voltmeter Note: The frontend is a completely preadjusted module. Only the IF filter must be adjusted to the IF amplifier (Adjustment 4). The values of the tuning voltages are as follows: 87.5MHz = typ. 1,6V; 108MHz = typ. 8.0V.
Adjustment 1. AM IF
Preparation AM; Sweep Generator 450kHz to AM Aerial Input; Ue > 60dBµV; Oscilloscope to Testpoint TP5, IC502(-19).
Adjustment Procedure Adjust with T503 for Maximum.
2. AM Oscillator
AM, 1620kHz; Digital Voltmeter to Testpoint TP3. AM; Couple Signal Generator via Loop Antennas; Ue > 50dBµV; fmod = 1kHz; Oscilloscope to Loudspeaker Output. FM, 98.0MHz Signal Generator to FM Aerial Input; Ue = 20dBµV; fmod = 1kHz; Deviation = 75kHz; Distortion Meter to Loudspeaker Outputs. FM; Signal Generator to FM Aerial Input; Ue = 50dBµV; fmod = 19kHz; Oscilloscope to Loudspeaker Outputs.
Adjust with T501 for 8.0V ± 0.2V.
3. AM Band Pass
Adjust alternating with L502 at 558kHz and with VC501 at 1440kHz for AF Maximum.
4. FM IF
Adjust with IF Filter A (under the cover) for Distortion Minimum.
5. 19kHz Filter
Adjust with LPF501 (left channel) and with LPF502 (right channel) for AF Minimum.
CD
Test equipment: Digital Voltmeter
Adjustment DC Offset
Preparation Mode CD; Digital Voltmeter between TP9 and TP10.
Adjustment Procedure Adjust with VR701 for 0V ± 0.1V.
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