NAD 3225PE - Alignment Method; Initial Adjustment Procedure; Final Adjustment Procedure

ALIGNMENT METHOD
AUDIO SECTION 3225PE/3020i
IMPORTANT
Speaker
impedance
switch
should
be
in
8
ohm
position
while
adjust
center
voltage
and
idling
current.
INITIAL ADJUSTMENT (No load connected)
A. CENTER VOLTAGE
1. Connector DC millivoltmeter to L channel output terminal.
2. Turn on and adjust to 0 V+/—30mV with R411 (470 ohm). Connect DC millivoltmeter
to R channel output terminal and adjust R412 to 0 V+/—30mV.
B. IDLING CURRENT
1. Remove solder short across R455 and R456.
2. Connect DC millivoltmeter across R455 (1 ohm) (output transistor’s collector resistor) and
adjust R443 for 26-30mV reading on meter. Repeat adjustment with R444, connecting meter
across R456 (1 ohm).
3. Leave power on for minimum 5 minutes.
FINAL ADJUSTMENT
C. CENTER VOLTAGE
1. Repeat step A about.
D. IDLING CURRENT
1. Repeat step B and adjust with R443, R444 for 30mV reading on meter.
2. After the alignment is finished, 1 ohm resistor R455, R456 is shorted by solder short.
R412 R41]
CENTER VOLTAGE ADJ \ | IDLING CURRENT ADI! CENTER OUTAGE AD!
IDLING CURRENT ADI