JL Audio JX400/4D Manuel D'utilisation page 14

APPENDIX C: TROUBLESHOOTING
"How do I properly set the input sensitivity on my amplifier"
"My amplifier doesn't turn on"
"My amplifier's output fluctuates when I tap on it or hit a bump"
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Please refer to Appeaset the input sensitivity for maximum, low-
distortion output.
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
"+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. If this
does not work, proceed to the next step.
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.
JL Audio