Marantz 2240 - Dolby FM Tape Output Setting; Audio Adjustment

Turn on MUTING pushswitch. Shift the FM signal generator frequency to plus and minus
and note both plus and minus shifted frequencies at which undesirable audio side responses
are muted out. Adjust the R363 so that the same shifted frequencies mute the undesirable
side response.
Adjust R362 for proper frequency shift at which the muting circuit operates.
. DOLBY FM TAPE OUTPUT SETTING
Set the modulation of FM SG to 400 Hz, 40% (+30 KHz Dev.)
Set the FM SG to provide 1 KuV at 98 MHz. Tune the receiver to the same frequency so
that. the center tuning meter pointer indicates its center.
Turn on DOLBY FM push switch. Set the semifixed resistors RCO1 and RCO2 so that the
output of the TAPE OUTPUT terminals R and L become 580 mV at VT. VM.
. AUDIO ADJUSTMENT
Voltage adjustment
Connect a DC voltmeter between pin terminal 804 and 805, and adjust the trimming resistor
R806 for 35V DC.
Main Amplifier DC off-set alignment
Connect a DC voltmeter with 0.5 or 1V range between the speaker terminals and adjust the
trimming resistor R707 for “zero’’ DC output on the meter.
Repeat the same procedure for the other channel.
Note: During this alignment no load should be connected to the speaker terminals.
{dle-current adjustment
Connect a VTVM between pin terminals 708 and 710. Next, adjust the trimming resistor
R719 for the VTVM reads 8mV DC. Repeat the same procedure for the other channel.
Check DC off-set voltage aligned in the procedure 2 and if any DC output is observed on the
DC voltmeter, adjust the R762 again for “‘zero’’ output.
Phono-amplifier adjustment
Connect a oscilloscope to the TAPE OUT jacks and an audio signal generator to the PHONO
jacks. Place the selector switch in the PHONO position. Increase 1 KHz audio signal
gradually until a slight clipping on top of the sine-wave is observed on the oscilloscope.
Adjust the trimming resistor R708 for equal clipping level.
For the other channel adjust R709.
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