4.16 -
GROUP
AlB MIXER AND LEFT/RIGHT AUDIO OUTPUT
TEST
1.
Select CHANNEL TEST
2.
Select AUDIO OUTPUT NOT 'MUTED
3.
Select C2 SINEWAVE, 5kHz SAMPLING RATE
4.
Assign
CHANNEL 1 with MINIMUM attenuation
°to
GROUP
A.
Assign
CHANNEL 2 with MINIMUM attenuation to
GROUP
B.
The GROUP A and GROUP B mixer outputs are available at the
following test points:
U125,
pin
1
U125,
pin
7
U126,
pin
1
U126,
pin
7
GROUP A mixer output
FEEDBACK A output
GROUP B mixer output
FEEDBACK B output
5.
Move the volume control slider
on
the K250 front panel
to
check the mixer gain control. The sinewave output should
decrease
in
amplitude as the slider is moved left, and
increase
in
amplitude as the slider
is
moved right.
NOTE:
The final output drivers will show clipping when the
volume slider is moved to the rightmost position.
The LEFT and
RIG
H T audio outputs are available at the
following
0 test points:
U9,
pin
1
U9,
pin
1
R29
right end
R30
right end
LEFT audio output
RIGHT audio output
LEFT audio output
RIGHT
audio output
Kurzwell 250 Service Manual, Chapter 4
4-29