JL Audio XD800/8v2 Handbuch Seite 17

"My amplifier shuts off once in a while, usually at higher volumes."
"My amplifier turns on, but there is no output."
Check your voltage source and grounding point. The power supply
of the XD800/8v2 will operate with charging system voltages
down to 10V. Shutdown problems at higher volume levels
can occur when the charging system voltage (or remote turn-
on voltage) momentarily drops below 10V. 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."
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 / high-pass application). A steady, sufficient voltage
(between 0.1 and 8.0-volts) should be present at the output of
the signal cables.
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. Remove the speaker wires from the amplifier
while doing this to prevent unpleasant noise and possible
speaker damage. Turn the volume up approximately half
way. 5V AC 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 terminal block. The
speaker wire connectors are designed to accept up to 8 AWG
wire. Make sure to strip the wire to allow for a sufficient
connection with the metal inside the terminal block.
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