Marantz 1250 - Page 3

1. POWER AMPLIFIER ADJUSTMENT
1.1 Adjustment of idling current
Connect VTVM between left. channel J715 and J716. Adjust R724 until the meter reads
10mV. Similarly, connect VTVM between right channel J715 and J716 and adjust R724 until
the meter reads 10mV.
1.2 DC-OFFSET adjustment
Connect VTVM to JN10 and JN14 (or ground) and adjust left channel R714 until the meter
indication reaches OmV (+5mV). Similarly, connect VTVM to JN11 and JN14 (or ground) and
adjust right channel R714 until the meter indication reaches OmV (+5mV).
2. POWER SUPPLY ADJUSTMENT
Connect a voltmeter between J810 and J812. Adjust R814 until meter indicates 55 VDC.
Similarly connect a voltmeter between J816 and J812. Adjust R815 until meter indicates —55
VDC.
105 TO 125VAC
§0/60 Hz
VARIAC
AC OUTLETS
AC WATTMETER
0 TO 150 WATTS
AC VOLTMETER
0 TO 150VAC
Figure 1. AC Power Control Box Simplified Schematic