Marantz ST610 - Page 5

2. TEST EQUIPMENT REQUIRED FOR SERVICING
This table lists the test equipment required for servicing the Model ST600 Tuner.
AM Signal Generator etn ee Signal source for AM alignment
[Testloop—SC—“‘idSSCSSCSCSCSCSCSSS
FM Signal Generator Sound Technology
MPX Signal Generator Mode! 1000A
Use with AM Signal Generator
Signal source for FM alignment
Stereo separation alignment and trouble
shooting
Distortion Analyzer Distortion measurements
Audio Oscillator ai ae Sinewave and squarewave signal source
AC VTVM One Voltage measurements (AC)
Tektronix Mode! T932 ,
Oscilloscope Philips Model 3232 Waveform analysis and trouble shooting
Fluke Model 1900A MPX Oscillator adjustment (VCO)
Fluke Model 8000 “‘Digital’’ Simpson
DC VTVM Model 313, Triplet Model 801 Voltage measurements (DC)
Simpson Model 1359 Monitors potential of primary power to tuner
. Superior Electronic Co., ee
Variable Autotransformer Powerstat Model 116B—10A Adjusts level of primary power to tuner
3. SCOPE DISPLAY ADJUSTMENT 4. AM ALIGNMENT PROCEDURES
1, Set the EXT LEVEL control to its fully counterclock- 4.1 AM IF Alignment
wise
position.
1.
Connect
a
sweep
generator
to
the
TC3
and
an
alignment
2. Depress the SCOPE DISPLAY ON and AUDIO push- scope to the R155.
switches in. 2. Rotate each core of IF transformers L152 and L151 for
3.
Adjust
the
HORIZ
and
VERT
controls
to
center
the
the
maximum
height
and
flat
top
symmetrical
response.
dot’ in the small circle in the center of the scope
- display. 4.2 AM Frequency Range and Tracking Alignment
4. Adjust the BRIGHT control (R001) on the rear panel 1. Set AM signal generator to 520 kHz. Turn the tuning
until the brightness becomes dark a little. capacitor fully closed (place the tuning pointer at the
5. Adjust the FOCUS control (R002) so that the spot low end) and adjust the oscillator coil 1.153 for maxi-
may be come smaller and circular. mum audio output. |
6. Turn the EXT LEVEL control to its fully clockwise 2. Set the signal generator to 1630 kHz. Place the tuning
position. | pointer in the high frequency end and adjust the os-
7. Connect a 150 mV, 1 kHz signal to the SCOPE IN- cillator trimmer on the oscillator tuning capacitor for
PUTS R jack and adjust R928 (H. GAIN) until the maximum audio output.
horizontal deflection is around 3 cm. 3. Repeat steps 1 and 2 until no further adjustment is
8. In turn, connect the same signal to the L jack and necessary.
similarly, adjust R927 (V. GAIN) until the vertical 4. Set the generator to 600 kHz, tune the tuner to the same
deflection is around 3 cm. frequency and adjust a slug core of AM ferrite-rod
9. Set the HOR!IZ and VERT controls to the 12-o’clock antenna LOO1 for maximum output.
position and adjust R925 (H. CENTER) until the spot 5. Set the generator to 1400 kHz and tune the tuner to the
comes in the horizontal deflection center. same frequency and adjust the trimming capacitor on
10. Similarly, adjust R926 (V. CENTER) until the spot the antenna tuning capacitor for maximum output.
comes in the vertical deflection center. 6. Repeat procedures 4 and 5 until no further adjustment is
necessary.
3.1 AM Tuning Display Adjustment
1. Depress the SCOPE DISPLAY ON and TUNING push- NOTE: During tracking alignment reduce the signal gen-
switches. erator output as necessary to avoid AGC action.
2. Depress the AM pushswitch.
3. Adjust R931 until the spot comes in the center below
the base line without tuning into a station.