Marantz SC-6 - Page 6

ADJUSTMENT
@ Line amplifier idling current adjustment
1. Connect a digital voltmeter to the following points:
L channel: Across the emitters of QL35 and OL37
(emitter side of RL61 and RL63).
R channel: Across the emitters of OL36 and QL38
(emitter side of RL62 and RL64).
REQUIRED MEASURING INSTRUMENTS
Table 1. List of required measuring instruments
2. Adjust RL45 (L ch). and RL46 (R ch.) until the digital
voltmeter reads 570 + 10 mV (61 mA) for each channel.
NOTE: This adjustment should be done 30 seconds after
the unit is powered ON.
Purpose
Distortion meter
Measures distortion in amplifier output and its voltage.
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Audio frequency generator
Oscilloscope
VTVM
AC power meter
Voltmeter
Slidac (0 ~ 140V AC, 10A)
Shorting plug
Output load resistor
(8Q + 0.5%, 250W)
Output load resistor
(4Q + 0.5%, 250W)
Signal source for audio-frequency sine and square waves.
Waveform analysis and troubleshooting.
Voltage and resistance measurement.
A
Monitors amplifier’s primary power consumption.
Monitors amplifier’s primary supply voitage.
Adjusts amplifier’s primary supply voltage.
Used to short input jacks for noise prevention.
Load to amplifier output (8Q).
Load to amplifier output (4Q).