Adjustment Points Diagram / Amplifier Adjustment - NAD T 743 Service Manual

ADJUSTMENT POINT DIAGRAM
FRONT/CENTER AMPLIFIER BOARD
P501 P502
SURROUND AMPLIFIER BOARD
P801
AMPLIFIER ADJUSTMENT
Idle Current
1. Rotate R522 fully clockwise.
2. Connect DC millivoltmeter to P501 (i.e. Across half of R523, 0.22 Ohm resistor).
3. Turn on the unit.
4. Adjust R522 for 1mV reading on voltmeter.
5. Leave power on for at least 5 min, and check for idle current again.
6. Repeat for other channels.
CHANNEL JUMPER
FL P501
FR P502
C P503
SL P801
SR P802
ISC Sensitivity
1. Connect 8 ohm loading to all channels.
2. Rotate R881 fully clockwise.
3. Load all channels at full power using 1kHz sine wave.
4. At this time, monitor the THD of the SL,SR output. Clipping should occur before full power achieved.
5. The procedure is finish at this step.
6. Load all channels at full power using 1kHz sine wave with 4 ohm load.
7. The clipping power(at THD 0.1%) should less than 85W.
P503
R835 R836
P802
VR
R522
R545
R571
R835
R836
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R522 R545 R571