Marantz PM-KI-PEARL-LITE, Service Manual

Page: 34 / 66

34
DC Offset Voltage Adjustment
Adjustment Procedure
Set the power voltage to rated voltage for this adjustment.
(1) Before turning on the power, Insert Digital Voltage Meter between the SPEAKERS SYSTEM A (L CH) "+" and "-".
Insert Digital Voltage Meter between the SPEAKERS SYSTEM A (R CH) "+" and "-".
(2) Adjust the VOLUME to MIN.
(3) Turn on the power. Then turn the SPAKERS SW to A.
Adjustment is started immediately after a speaker relay turns on.
(4) First L CH is adjusted.
The variable resistor R639 on P101 is turned with adjustment driver, and the Digital Voltage Meter is adjusted to "0
mV ± 3 mV".
(5) Then, R CH is adjusted.
The variable resistor R640 on P101 is turned with adjustment driver, and the Digital Voltage Meter is adjusted to "0
mV ± 3 mV".
NOTE : DC offset voltage drops when turn the semi-fixed resistor (R639 and R640) clockwise. DC offset voltage rises
when turn the semi-fixed resistor un-clockwise. Please turn it slowly, because value of Digital Voltage Meter
changes slowly.
(6) Although after-adjustment DC offset voltage has some change, Please check that the range of DC offset voltage
between L ch (R ch) "+" and L ch (R ch) "-" terminal of SPEAKERS SYSTEM A is "0 mV ± 20 mV". CHART OF
FACTORY MODE.
Digital Voltmeter
Digital Voltmeter
R ch
V
L ch
V
P101
R639
R640