Bose FreeSpace IZA 190-HZ Service Manual page 102

7. Channel Separation Test
Note: A 20kHz filter and A-weighting must be
used for this test.
7.1 On the rear panel, apply a 1kHz, -20dBv
+/- 2dBv sine wave to the Input A RCA input
jack. Increase the input signal level until you
see a 10W output level at the Output 1
connector. Measure the output level at the
Output 2 connector. It should be -60dB,
+10dB max.
7.2 On the rear panel, apply a 1kHz, -20dBv
+/- 2dBv sine wave to the Input B RCA input
jack. Increase the input signal level until you
see a 10W output level at the Output 2
connector. Measure the output level at the
Output 1 connector. It should be -60dB,
+10dB max.
7.3 On the front panel, apply a 1kHz, -20dBv
+/- 2dBv sine wave to the + side (tip) of the
Aux Input jack. Increase the input signal level
until you see a 10W output level at the
Output 1 connector. Measure the output level
at the Output 2 connector. It should be -
60dB, +10dB max.
7.4 On the front panel, apply a 1kHz, -20dBv
+/- 2dBv sine wave to the - side (ring) of the
Aux Input jack. Increase the input signal level
until you see a 10W output level at the
Output 2 connector. Measure the output level
at the Output 1 connector. It should be -
60dB, +10dB max.
8. Aux Output Level and THD Test
8.1 On the front panel, set the master level
control to maximum (fully CW). On the rear
panel, set the Input A gain to maximum (fully
CW).
8.2 Apply a 1kHz, -12dBV sine wave to the
Input A RCA jacks. Measure the output level
at the Aux Out RCA jacks on the rear panel.
It should be -3dBv +/- 1dBv.
TEST PROCEDURES
102
8.3 With the output level specified in step 8.2
above, measure the THD level at the Aux
Out RCA jacks. It should be <0.1%. 0.02%
is ideal.
Note: You will need a 20kHz filter for this
test.
9. Aux Output Frequency Response and
Noise Test
9.1 On the front panel, set the master level
control to maximum (fully CW). On the rear
panel, set the Input A gain to maximum (fully
CW).
9.2 Apply a 1kHz, -12dBV sine wave to the
Input A RCA jacks. Measure the output level
at the Aux Out RCA jacks on the rear panel.
It should be -3dBv +/- 1dBv. Reference a dB
meter to this output level.
9.3 Change the input signal frequency to
60Hz. Verify that the output level is -3dBr
+/- 1dBr.
9.4 Change the input signal frequency to
18kHz. Verify that the output level is -1dBr
+/- 1dBr.
9.5 Set the input signal frequency to 1kHz.
Measure the output noise level at the Aux
Out jacks. It should be < -88dBv. Ideal is
-90dBv.
Note: You will need a 20kHz filter with A-
weighting for this test.
10. Input Priority Test
10.1 Apply a 1kHz, -10dBv +/- 2dBv audio
signal to inputs A and B on the rear panel.
Verify that the Source Select switch on the
front panel switches between Inputs A and B.
10.2 Apply an audio signal to the 1/8" input
jack on the front panel. Verify that the input
connected to the 1/8" input jack overrides
the inputs to A and B on the rear panel.