QSC KSub - Front LED

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QSC Audio Products, LLC
• If the faston connector was disconnected from the transducer terminal, it’s
recommended to crimp a brand new faston connector. For the LF green
and green/black wire, use a 0.205” or 5.21 mm female, 14–16 AWG,
insulated straight faston. For the HF yellow and yellow/black wire, use a
0.250” or 6.35 mm female, 14–16 AWG, insulated straight faston.
• Inspect all six wires in the wiring harness. Gently pull each one separately
to make sure it is well secured in the black Molex connector. If any wire
is loose and easily pulls out of the connector, replace the wiring harness
assembly - do not repair it.
• The wiring harness should be slack enough to not put excessive stress on
the connections, but taut enough that the wires will not flop around and
possibly make noise. If the harness wires are too taut, cut off the tie-wraps
and install new ones in a way that provides more slack. Attach the wires to
the driver terminals, while making sure the polarity is correct.
9.9 Front LED
Due to possible vibration issues, component problems, or a short circuit in the wire, the front blue LED can burn out. This
repair is not easy and can take at least an hour of labor to finish. While only the blue LED needs to be replaced (QSC part
number QD-000312-GP), the front grille and baffle assembly must be removed from the main enclosure to access the
LED.
Symptoms:
• Front LED is not working, even with setting on the BOP as “FRONT LED” or “LIMIT”.
Failure verification:
• The BOP is outputting a voltage through the black Molex connector but the front LED is not illuminated. The front LED
setting is on “FRONT LED”.
Repair notes:
• Remove the BOP first. Before replacing the LED, always verify that the BOP is outputting a voltage through the Molex
connector with the wiring harness disconnected.
• Remove the front grille then the main baffle (you can keep the transducers installed to the baffle. Set the baffle assembly
on a flat work surface to begin replacement of the LED.
• The glue that holds the LED in place can be tough to remove. Carefully chip away the glue and try not to damaging the
wires.
• Order a new wiring harness just in case the current one is damaged during repair.
• Reuse the existing plastic spacer if possible. Before soldering the new LED to the wires, slip a piece of small heat shrink
tubing on each wires Then solder the LED’s long lead (anode) to the white wire and its short lead (cathode) to the black
wire. Cover the soldered connections with the heat shrink tubing and apply heat to shrink it. Make sure the wires cannot
touch.
• Put the LED and plastic spacer back into the hole and apply hot glue to secure it in place. Make sure the LED wires are
routed neatly between the edge of the woofer and the port. Add more hot glue to secure the wires, if needed.
Figure 9.11 - Wiring harness connector
Figure 9.13 - Glue covering the front LEDFigure 9.12 - Front LED wire routing