Marantz 2220B - AM Alignment Procedure; AM IF Alignment; AM Frequency Range and Tracking Alignment

7. TEST EQUIPMENT REQUIRED FOR SERVICING
Table 1 lists the test equipment required for servicing the Model 2220B Receiver.
Item Manufacturer and Mode! No. Use
AM Signa! Generator Signa! source for AM alignment
Test Loop
FM Signal Generator Less than 0.3% distortion
Less than 0.3% distortion
Use with AM Signal generator
Signal source for FM alignment
Stereo Separation alignment and trouble
shooting
Stereo Modulator
Weston Model CVO-100P, less
than 0.02% residual distortion
is required.
Audio Oscillator Sinewave and squarewave signal source.
MPX Oscillator adjustment (VCO)
Waveform analysis and Trouble Shooting, and
ASO alignment.
Frequency Counter
High sensitivity with DC
horizontal and vertical
Oscilloscope
amplifiers.
Circuit Tester em ee ae Trouble Shooting
AC Wattmeter Simpson, Model 390 Monitors primary power to Amplifier.
AC Ammeter Commerical Grade (1-10A) Monitors amplifier output under short
circuit condition.
Line Voltmeter Commercial Grade (0-150VAC)| Monitors potential of primary power to
amplifier.
Variable Autotransformer Powerstat, Model 116B Adjusts level of primary power to amplifier.
(0-140VAC, 10 amps.)
Shorting Plug Use phono plug with 600 ohm | Shorts amplifier input to eliminate noise
across center pin and shell. pickup.
Output Load (8 ohms, Commercial Grade Provides 8-ohm load for amplifier output
0.5%, 100W) termination.
‘Output Load (4 ohms, Commercial Grade Provides 4-ohm load for amplifier output
0.5%,
100W)
termination.
8. AM ALIGNMENT PROCEDURE
AM._IF Alignment
1. Connect a sweep generator to the J106 and an alignment scope to the resistor R120 (out
side).
2. Rotate each core of IF transformers L110 and L111 for the maximum height and flat top
symmetrical response.
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 L109 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 step 1 and 2 until no further adjustment is necessary.
4, Set the generator to 600 KHz, tune the receiver to the same frequency and adjust a slug core
of AM ferrite rod antenna and RF coil L108 for maximum output.
5. Set the generator to 1400 KHz and tune the receiver to the same frequency and adjust both
trimming capacitor of antenna and RF tuned circuit for maximum output.
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