Marantz 2110 - Test Equipment Required; AM Tuning Display Adjustment; Am Alignment Procedures; AM Frequency Range and Tracking Alignment

2. TEST EQUIPMENT REQUIRED FOR SERVICING
This table lists the test equipment required for servicing the Model 2110 Tuner.
item
AM Signal Generator
Test Loop
Sound Technology
Model 1000A
FM Signal Generator
MPX Signal Generator
Manufacturer and Model No.
Use
Signal source for AM alignment
Use with AM Signal Generator
Signal source for FM alignment
Stereo separation alignment and trouble
shooting
Distortion Analyzer
Audio Oscillator
AC VTVM
Sound Technology
Model 1700A
Distortion measurements
Sinewave and squarewave signal source
Voltage measurements (AC)
Tektronix Mode! T932
Philips Model 3232
Oscilloscope
Waveform analysis and trouble shooting
Frequency Counter Fluke Model 1900A
MPX Oscillator adjustment (VCO)
Circuit Tester
Trouble shooting
DC VTVM |
Fluke Model 8000 ‘‘Digital’’ Simpson
Model 313, Triplet Mode! 801
Voltage measurements (DC}
AC Wattmeter Simpson Model 1379
Monitors primary power to tuner
Line Voltmeter Simpson Model 1359
Monitors potential of primary power to tuner
Superior Electronic Co.,
Variable Autotransformer
3. SCOPE DISPLAY ADJUSTMENT
1. Set the EXT LEVEL control to its fully counterclock-
wise position.
2. Depress the SCOPE DISPLAY ON and AUDIO push-
switches in.
3. Adjust the HORIZ and VERT controls to center the
dot in the small circle in the center of the scope
display.
4, Adjust the BRIGHT control (R001) on the rear panel
until the brightness becomes dark a little.
5. Adjust the FOCUS control (R002) so that the spot
may be come smaller and circular.
6. Turn the EXT LEVEL control to its fully clockwise
position.
7. Connect a 150 mV, 1 kHz signal to the SCOPE IN-
PUTS R jack and. adjust R928 (H. GAIN) until the
horizontal deflection is around 3 cm.
8. In turn, connect the same signal to the L jack and
similarly, adjust R927 (V. GAIN) until the vertical
deflection is around 3 cm.
9. Set the HORIZ and VERT controls to the 12-o’clock
position and adjust R925 (H. CENTER) until the spot
comes in the horizontal deflection center.
10. Similarly, adjust R926 (V. CENTER) until the spot
comes in the vertical deflection center.
3.1 AM TUNING DISPLAY ADJUSTMENT
1. Depress the SCOPE DISPLAY ON and TUNING push-
switches.
2. Depress the AM pushswitch.
3. Adjust R931 until the spot comes in the center below
the base line without tuning into a station.
Powerstat Model 116B—10A
Adjusts level of primary power to tuner
4. AM ALIGNMENT PROCEDURES
4.1 AM IF ALIGNMENT
1,
Connect a sweep generator to the TC3 and an alignment
scope to the R155.
2. Rotate each core of IF transformers L152 and L151 for
the maximum height and flat top symmetrical response.
4.2 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 L153 for maxi-
mum audio output.
. Set the signal generator to 1650 kHz. Place the tuning
pointer in the high frequency end and adjust the os-
cillator trimmer on the oscillator tuning capacitor for
maximum audio output.
. Repeat steps 1 and 2 until no further adjustment is
necessary.
. Set the generator to 600 kHz, tune the tuner to the same
frequency and adjust a slug core of AM ferrite-rod
antenna LOO1 for maximum output.
. Set the generator to 1400 kHz and tune the tuner to the
same frequency and adjust the trimming capacitor on
the antenna tuning capacitor for maximum output.
. Repeat procedures 4 and 5 until no further adjustment is
necessary.
NOTE: During tracking alignment reduce the signal gen-
erator output as necessary to avoid AGC action.