JL Audio M600/6 Owner's Manual

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16  |  JL Audio - M600/6 Owner’s Manual  
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“My amplifier shuts off once in a while, usually at higher volumes.”
 Check 
 
your voltage source and grounding point. The power supply 
of the M600/6 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 
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voltage, inspect all wiring and termination points. It may 
also be necessary to upgrade the ground wire connecting 
the battery to the vessel’s electrical ground and the power 
wire connecting the alternator to the battery. Many vessels 
employ small (10 AWG - 6 AWG) wire to ground the battery 
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 
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“My amplifier turns on, but there is no output.”
 Check 
 
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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  
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range / high-pass application).  A steady, sufficient voltage 
(between 0.1 and 4.0-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 
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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.
“How do I properly set the input sensitivity on my amplifier?”
 Please 
 
refer to Appendix A (page 14) to set the input sensitivity for 
maximum, low-distortion output.
“My amplifier doesn’t turn on.”
 Check 
 
the fuse, 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 
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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 
i+12VDCw wire 
to the 
iRemotew terminal to see if the amplifier turns on. 
 
“I hear a repetitive ticking or popping 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 vessel’s electrical 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  
2 ohms in stereo mode (4 ohms bridged). 
 
“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 terminal block. 
 
Check  the input connectors to ensure that they all are making good 
contact with the input jacks on the amplifier. 
APPENDIX D:  TROUBLESHOOTING