NAD 3240PE - Service Alignment Procedure; Initial Voltage and Current Setup; Final Adjustment and Checks

ALIGNMENT
METHOD
AUDIO SECTION
3240PE
IMPORTANT
Speaker
Impedance
switch
should
be
in
8 ohm
position
while
adjusting center
volatge
and idling
current.
INITIAL
ADJUSTMENT
(No
load
connected)
A.
CENTER
VOLTAGE
1,
Connect
OC
mill
i
voltmeter
to L
channel
output
terminals.
2.
Turn
on and
adjust
to 0
V
*-
30mV
with
VR4Q1
(10KB).
Connect DC
millivoltmeter
to
R
channel
output
terminals
and
adjust
VR402
to
0
V
+-
30mY.
B.
IDLING
CURRENT
1.
Remove
solder
short across
R47
1
and R472.
2.
Connect
DC
nillvoltmeter
across
R471 (I ohm) (output transistor’s
collector
resistor)
and adjust
VR403
(1KB)
for
26
-30mY
reading
on
meter.
Repeat
adjust
with YR404
(1KB),
connecting meter across
R472(
1 ohm)
3. leave
power
on
for
minimum
.5
minutes.
FINAL
ADJUSTMENT
C.
CENTER
VOLTAGE
1.
Repeat
step A above.
D. IDLING
CURRENT
1.
Repeat step
8
and
adjust
with
VR403,
YR404
for
30mY reading
on meter.
2.
After
the alignment
is
finished, 1 ohm
resistor
R47
I
,R472
is shorted
by
solder short.
AMPLIFIER
ADJUSTMENT
POINTS