Marantz 4270 - FM Alignment Stereo Separation; FM Alignment Muting Circuit; Marantz 4270 Dolby Alignment Procedure

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19.2 Muting Circuit Alignment
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Connect a VTVM across the resistor R363 and adjust the resistor R363 until the meter reads
0.75V DC at no signal.
Set the FM SG to provide 1 KuV at 98MHz and tune the receiver to the same frequency
correctly.
Turn on MUTING pushswitch. Shift the FM signal generator frequency to plus and minus
and note both pius 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.
AUDIO ADJUSTMENT
Connect a VTVM to J713(+) and J724(—) and adjust the trimming resistor R766 until the
VTVM reads 10mV DC. For the other channel connect the VTVM to J714 (+) and J725(—)
and adjust the R767 for the same reading.
Connect a VTVM to J724(+) and J723(—) and adjust the trimming resistor R713 until the
VTVM reads OV DC. For the other channel connect the VTVM to J725(+) and J723(—)
and adjust the R714 until the VTVM reads OV DC.
AUTOMATIC VOLTAGE REGULATOR ADJUSTMENT
Connect a VTVM to J813(+) and J803(—) and adjust R807 until the VTVM reads 35V
under no signal condition.
22.
DOLBY ALIGNMENT PROCEDURE
Prior to the adjustment, turn the PLAY CAL and REC LEVEL controls all the way
to the right and the SELECTOR switch to the CD-4/AUX position. Use the CD-4/AUX and
TAPE MONITOR OUT jacks for the signal! input and output.
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Set the DOLBY switch to the RECORD | position.
Adjust the semi-fixed resistor R653 for maximum source voltage of the field-effect transistor
H611.
Connect J620 and J613 to the ground.
Apply a 5KHz sine wave so as to obtain 17.5mV at J605.
Record the output level at the TAPE MONITOR OUT jack with the above signal applied.
Adjust the semi-fixed resistor R659 so that the output level at the TAPE MONITOR OUT
jack may increase 10+0.25dB when J620 is disconnected from the ground.
Record the above output level.
Adjust the semi-fixed resistor R653 so that the output level may decrease 2+0.25dB when
J613 is disconnected from the ground.
Connect J613 to the ground again, and assure the level increase in the step (6) above.
Disconnect J613.
Set the DOLBY switch to the RECORD II position.
Connect J620 and J613 to the ground.
Apply a 5KHz sine wave so as to obtain a 44mV at J605.
Check to insure that the level at the TAPE MONITOR OUT jack decreases 10+0.5dB when
J620 is disconnected from the ground.
Disconnect J620 and J613 from the ground.
Check to insure that the output voltage at the TAPE MONITOR OUT jack is 17.5mV
(£0.5dB).