Bose 1600-VI, Руководство по обслуживанию

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TEST PROCEDURES
3. Distortion Level
3.1
Apply a 1.5 Vrms, 1 kHz signal for low
sensitivity units, or a 775 mVrms, 1 kHz
signal for high sensitivity units, to the
amplifier channel under test.
3.2
Set the CH1 or CH2 level controls, as
appropriate, to the full on position (fully
clockwise).
3.3
Measure the distortion level. It should
be ≤ .2% THD.
4. DC Offset
4.1
With no signal applied, measure the
DC voltage level at the amplifier output.
4.2
It should be ≤ 35 mVdc.
5. Overcurrent Shut Down Test
5.1
Apply a 1.0 Vrms, 1 kHz signal to the
amplifier channel under test.
5.2
Use a 0.1 Ω , 50 W resistor to simulate
a short circuit across the amplifier channel
under test. Do not apply a dead short
across the amplifier output as damage
could result. Test duration should be ap-
proximately 5 seconds.
5.3
The amplifier protection circuit should
cause the output relays to drop out, remov-
ing the output signal from the binding
posts. After a short period, the amplifier
should attempt to come out of protect
mode. If the short is still applied, the ampli-
fier should stay in protect mode.
Once the short is removed, the output
relays should stay on and provide signal
output to the binding posts.
6. Thermal Shut Down Test
6.1
Remove the top cover using Disassem-
bly/Assembly procedure 1.
6.2
Apply a 16 mVrms, 1 kHz signal to the
input jacks of both channels of the amplifier
under test.
6.3
On the amplifier PCB, locate RT100
and RT200. They are located near the
corners of the PCB. See the amplifier PCB
layout diagram for more information.
6.4
Apply a short to RT100. Verify that the
appropriate protection LED for CH 1 illumi-
nates on the front panel and that the fan
speed increases while RT100 is shorted.
6.5
Remove the short on RT100.
6.6
Apply a short to RT200. Verify that the
appropriate protection LED for CH 2 illumi-
nates on the front panel and that the fan
speed increases while RT200 is shorted.
6.7
Remove the short on RT200 and
replace the top cover using Disassembly/
Assembly procedure 2.
7. Channel Imbalance Test
7.1
Apply a 775 mVrms, 1 kHz signal to
both channels of the amplifier under test.
7.2
With both gain pots on the front panel
fully CW, reference a dB meter to the
output level of one channel.
7.3
Measure the output level on the other
channel of the amplifier. There should be
less than a 0.5 dB difference between
channels.