Marantz 2250B free download

File name 2250B.pdf

3. AM ALIGNMENT PROCEDURE (~ 3.1 AM I F Alignment ( ) 1. Connect a sweep generator to the J 153 and an alignment scope to the test point B. 2. Rotate each core of I F transformer L 153 for maximum height and flat top symmetrical response. 3.2 AM Frequency Range and Tracking Alignment 1. Set AM signal generator to 515 kHz. Turn the tuning capacitor fully closed (place the tuning pointer at the low end) and adjust the oscillator coil L 152 for maximum audio output. 2. Set the signal generator to 1650 kHz. Place the tuning pointer in the high frequency end and adjust the oscillator trimmer on the oscillator tuning capacitor for maximum audio output. 3. Repeat steps 1 and 2 until no further adjustment is necessary. 4. Set the generator to 600 kHz and tune the receiver to the same frequency anq adjust a slug core of AM ferrite rod antenna and RF coil L 151 for maximum output. 5. Set the generator to 1400 kHz and tune the receiver to the same frequency and adjust both trimming capacitors of antenna and RF tuned circuit for maximum output. 6. Repeat steps 4 and 5 until no further adjustment is necessary. Note: During tracking alignment reduce the signal generator output as necessaryto avoid AGC action. 3.3 AM Signal Strength Meter Alignment Set an AM signal generator to 1000 kHz at 5k1-N, and adjust R178 so that the signal strength meter may read 90% of the full scale. 4. FM ALIGNMENT PROCEDURE 1. ,Connect an FM signal generator to the FM ANTENNA terminals and an oscilloscope and an audio distortion analyzer to the TAPE OUTPUT jacks on the rear panel. 2. Set the FM SG to 87 MHz and provide about 3 to 5J.1.V. Place the tuning pointer at the low frequency end by rotating the tuning knob and adjust the core of oscillator coil L 104 to obtain maximum audio output. 3. Set the FM SG to 109 MHz and provide about 3 to 5J.1.V output. Rotate the tuning knob and place the tuning pointer at the high frequency end and adjust the trimming capacitor C106 for maximum output. 4. Repeat steps 2 and 3 until no further adjustment is necessary. 5. Set the FM SG to 90 MHz and tune the receiver to the same frequency. Decrease signal generator output until the audio output level decreases with the decreasing generator output. Adjust the antenna coil L101, RF coils L102 and L103 and I F transformer L 105 for minimu