JBL GX-A604, Service Manual

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If your amplifier isn’t performing the way you think is should, check to see if the problem is covered in this section before calling your dealer or
contacting JBL customer service.
PROBLEM CAUSES AND SOLUTIONS
No sound (the amplifier’s Power LED is off) • Check that the amplifier’s +12 V and GND connections have been properly made.
• Check if the fuse on the +12 V wire located near the battery is blown: If so, replace it with an
identical fuse.
• Check all amplifier fuses; if any are blown, replace them with identical fuses.
• If you are using the amplifier’s REM connection for turn-on, check that the wire is properly
connected to the audio system’s remote turn-on wire or to the vehicle’s ACC power terminal.
No sound (the amplifier’s Power LED is orange) • Check that all amplifier input and speaker connections have been properly made.
• Check that the amplifier’s Level controls are not turned all the way down (counter-clockwise).
• Check that the vehicle audio system’s source unit’s volume control is not turned all the way
down.
No sound (the amplifier’s Protection LED is red) • Confirm that the vehicle’s electrical system is supplying between 9 V and 16 V DC to the
amplifier. If the supply voltage is outside of this range, correct the condition before attempting to
use the amplifier.
• If the amplifier has overheated, wait until it has cooled down before attempting to use it again.
• Disconnect all speakers from the amplifier and attempt to turn it on again:
– If the amplifier turns on (the Power LED is orange), there is a short circuit in one or more of the
speaker wires. Correct all short circuits before reconnecting the speakers to the amplifier.
– If the amplifier does not turn on (the Protection LED is still red and the Power LED is off),
contact your authorized JBL dealer for assistance.