JL Audio HD900/5 owner manual My amplifier doesn’t turn on

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Appendix D: TROUBLESHOOTING

“How do I properly set the input sensitivity on my amplifier”

Please refer to Appendix C (pages 18, 19) to set the input sensitivity for maximum, low-distortion output.

“My amplifier doesn’t turn on”

Check the fuse(s), not just visually, but with a continuity meter. It is possible for a fuse to have poor internal connections that cannot be found by visual inspection. It is best to take the fuse out of the holder for testing. If no problem is found with the fuse, inspect the fuse-holder.

Check the integrity of the connections made to each of the “+12VDC”, “Ground”, and “Remote” terminals. Ensure that no wire insulation is pinched by the terminal set screw and that each connection is tight.

Check to make sure there is +12V at the “Remote” connection of the amplifier. In some cases, the turn-on lead from the source unit is insufficient to turn on multiple devices and the use of a relay is required. To test for this problem, jump the “+12VDC” wire to the “Remote” terminal to see if the amplifier turns on.

“I get a distorted / attenuated sound coming out of the speaker(s)”

Check the speaker wires for a possible short, either between the positive and negative leads or between either speaker lead and the vehicle’s chassis ground. If a short is present, you

will experience distorted and/or attenuated output. The “Status” LED will turn amber (yellow) in this situation. It may be helpful to disconnect the speaker wires from the amplifier and use a different set of wires connected to a test speaker.

Check the nominal load impedance to verify that each channel of the amplifier is driving a load equal to or greater than 1.5 ohms in stereo mode (3 ohms bridged).

Check the input signal and input signal cables to make sure signal is present at the “Amplifier Inputs” and the cables are not pinched or loose. It may be helpful to try a different set of cables and/or a different signal source to be sure.

Reset the amplifier by removing the power plug, then wait ten seconds and reconnect the power plug.

“My amplifier’s output fluctuates when I tap on it or hit a bump”

Check the connections to the amplifier. Make sure that the insulation for all wires has been stripped back far enough to allow a good contact area inside the connector plugs.

Check the input connectors to ensure that they all are making good contact with the input jacks on the amplifier.

20 JL Audio - HD900/5 Owner’s Manual

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Contents Channel Class-D System Amplifier Installation Applications Planning Your InstallationProtect Your Hearing Serial NumberSafety Considerations Cooling Efficiency ConsiderationsYour JL Audio amplifier employs an Stupid Mistakes to AvoidProduct Description As we said, it’s very flexibleConnect the RCA input cables To the amplifier Typical Installation SequenceRun power wire from the battery location +12V Battery Connection Power Wire RequirementsFuse Requirements Ground ConnectionTurn-On Wire Amplifier Power Connector PlugHD900/5 has two mounting options to ease in installation Standard MountingLateral Mounting Feet Security cover is secured by a singleInput Mode Switch Ch. Input ModeInput Voltage Switch Amplifier INPuTSChannel Control Sections Input Sens. ControlsFilter Freq. Hz Control Infrasonic Filter Subwoofer Ch. OnlyAfter proper adjustment of the HD900/5’s Bi-AmpLIFIED SYSTEMSREmote level control Optional Standard telephone cable supplied with the HD-RLCMultiple phone cables Speaker OutputsSpeaker Connector Plugs Status LED / Protection Circuitry Servicing your JL Audio Amplifier JL Audio Technical SupportAppendix a HD900/5 Specifications Chassis Dimensions LxWxHCrossover Filters Input SectionsNecessary Equipment Appendix B  Precise Frequency Selection ChartFull-clockwise Appendix C Increase the Input Sens. control until Nine-Step ProcedureChannels at 3/4 source unit volume My amplifier doesn’t turn on My amplifier turns on, but there is no output INSTALLATION NOTES Page Limited Warranty Amplifiers USA If you need service on your JL Audio productJL Audio, Inc International Warranties