Adjustment Point Diagram; Front/Center Amplifier Board; Surround Amplifier Board; Amplifier Adjustment - NAD T 763 Service Manual

ADJUSTMENT POINT DIAGRAM

FRONT/CENTER AMPLIFIER BOARD

R522 R545 R571

SURROUND AMPLIFIER BOARD

R835 R836 R897
P801
ISC BOARD
R881

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
BS P803
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,BS output. Clipping should occur before full power
achieved.
5. Rotate R834 counter-clockwise slowly until the THD just below 0.1%.
6. Repeat step 2-5 for R834 but monitor FL, FR & Center output.
7. The procedure is finish at this step.
8. Load all channels at full power using 1kHz sine wave with 4 ohm load.
9. The clipping power(at THD 0.1%) should less than 85W.
P501
P502
P802
VR
R522
R545
R571
R835
R836
R897
13
P503
P803
R834