JBL GTQ360, GTQ240 owner manual In Case of Difficulty, Power-onlight does not come on

8. In Case of Difficulty

Power-on light does not come on

•Head unit not on; turn the head unit on.

•Ground wire is disconnected or defec- tive; check for continuity with an ohm- meter between the amplifier’s ground ter- minal and a known chassis ground point.

•Battery wire is disconnected or defec- tive; check for approximately +12 volts between the amplifier’s battery and ground terminals.

•Blown fuse; check amplifier’s fuses located on the end panel near the power connector. If they are blown, replace them with identical ones. If the new fuses blow immediately, check all the wiring connec- tions. If the source of the problem cannot be determined, consult your JBL dealer.

•Remote-on wire between the head unit and the amplifiers is disconnected or defective; check for +12 volts between amplifier's remote-on input terminal and the ground wire with the head unit on.

Power light is on, but no sound is heard from some or all of the speakers

•Incorrect switch settings; make sure that all switches (mode, input and crossover) are in their correct positions for your sys- tem configuration.

•Incorrectly connected or shorted speaker wires; check for shorts in wiring.

•Defective or disconnected audio cables; check for continuity and replace if necessary.

•Incorrect gain adjustment; verify that the amplifier gain controls are not turned completely down. If they are, sound out- put level may be very low and may give the impression that the system (or part of the system) is dead.

Power light is on, but no sound is heard from some or all of the speakers

•Defective head unit or signal processor; check each component for proper wiring and operation.

•Defective GTQ amplifier; if there is audio signal present at the inputs of the amplifi- er and there is no output, the GTQ amplifi- er may be defective.

Alternator whine through the audio sys- tem with the engine running

•Ground loops; follow the wiring sugges- tions in the section called “Solving Noise Problems.” Also, verify that the chassis grounding point you have chosen is true ground by checking for continuity between the chassis ground point and battery ground.

Bass output from speakers too low

•Speaker wired out of phase; check for proper polarity on all speaker wiring (+ amp terminal to + speaker terminal and – amp terminal to – speaker terminal).

Power light is blinking and no sound is heard

•Incorrectly connected or shorted speaker wires; check for shorts in wiring.

•Defective GTQ amplifier; if there is no short on the speaker outputs, the GTQ amplifier may be broken. Consult your JBL dealer.

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