Testing - QSC K8 Service Manual

8. Testing

8.1 Requirements
Hardware
• Digital multimeter (DMM)
• Oscilloscope
• Audio sine wave generator
• SPL meter
• Soldering iron
• K Family test adapter
• Distortion analyzer (Audio Precision recommended)
• Class D output filter for distortion analyzer
8.2 Bucket of power testing
Molex pinout (output connector)
The molex jack, which connects to the speaker's internal
wiring harness, is located on the back of the BOP. Channel
1 and channel 2's outputs can be tested from the molex
jack. The K8/K10/K12 PSU/amp boards have both normal
(filter bypass) and high-pass filtering connections available
on the molex jack. Because of this, it's important to deter-
mine which molex pins are being measured when testing
channel 2's output.
K Family test adapter
QSC Technical Services Group offers an output adapter for testing any K, KW,
or KLA series BOP. The adapter includes a switch for testing channel 2's nor-
mal and high-pass filtering sections. It also includes a front LED for test. This
adapter is highly recommended for troubleshooting and testing the output
power of the amplifier. Please call and ask for QSC part number SG-000576-
TS.
Activating "test mode"
When the BOP is running in "test mode" it acts like a full-range 2 channel
amplifier that can pass frequencies from 20 Hz to 20 kHz at full power. All
DSP voicing is ignored while in test mode, however the signal will still pass
through the DSP controller. Test mode is required if verifying full power output
from the amplifier but can also be useful when troubleshooting the BOP.
To activate test mode:
1. Disconnect AC and turn off the BOP. Remove the gain knob on the right
side of the amplifier (channel B for K8/K10/K12 models).
2. Locate the two triangular-shaped pads on the PCB next to the gain poten-
tiometer or near the text "SHORT FOR TEST MODE" as in Figure a.
3. Solder the two pads together so that the pads are shorted or bridged.
4. The BOP is now in Test Mode.
Audio Precision (AP) Test Procedures
If an Audio Precision distortion analyzer is available, please contact QSC for
the test procedure files. They are available upon request. A test adapter is
required if using the AP test procedures.
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Figure 8.1 - Molex output connector pinout
Figure 8.2 - Test adapter for K Family
Figure 8.3 - Test mode activated
QSC Audio Products, LLC