“My amplifier shuts off once in a while, usually at higher volumes”
Check your voltage source and grounding point. The power supply of the HD900/5 will operate with charging system voltages down to 9V. Shutdown problems at higher volume levels can occur when the charging system voltage drops below
9V. These dips can be of very short duration making them extremely difficult to detect with a common DC voltmeter. To ensure proper voltage, inspect all wiring and termination points. It may also be necessary to upgrade the ground wire connecting the battery to the vehicle’s chassis and the power wire connecting the alternator to the battery. Many vehicles employ small (10 AWG - 6 AWG) wire to ground the battery to the vehicle’s chassis and to connect the alternator to the battery. To prevent voltage drops, these wires should be upgraded to 4 AWG when installing amplifier systems with main fuse ratings above 60A. Grounding problems are the leading cause of misdiagnosed amplifier “failures.”
“My amplifier turns on, but there is no output”
Check the input signal using an AC voltmeter to measure the voltage from the source unit while an appropriate test tone is played through the source unit (disconnect the input cables from the amplifier prior to this test). The frequency used should be in the range that is to be amplified by the amplifier (example: 50 Hz for a sub bass application or 1 kHz for a full range /
Check the output of the amplifier. Using the procedure explained in the previous check item (after plugging the input cables back into the amplifier) test for output at the speaker outputs of the amplifier. Unless you enjoy test tones at high levels,
it is a good idea to remove the Speaker Connector Plugs from the amplifier while doing this. Turn the volume up approximately half way. 5V or more should be measured at the speaker outputs. This output level can vary greatly between amplifiers but it should not be in the millivolt range with the source unit at half volume. If you are reading sufficient voltage, check your speaker connections as explained below.
Check to ensure that the speaker wires are making a good connection with the metal inside the Speaker Connector Plugs. The speaker wire connectors are designed to accept up to 12 AWG wire. Make sure to strip the wire to allow for a sufficient connection with the metal inside each terminal.
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