Boat Forum / Electronics / July 2008

Somewhere in the DC supply lines, including the negative side don't
forget, there is a corroded connection in a plug, terminal block, fuse
block or the fuse holder itself.

At high volumes, a stereo draws a LOT of PEAK current through this
corroded connection in series with the DC power supply.

When an audio peak causes a peak voltage drop at the corrosion so high
it leaves a less-than-acceptable voltage on the DC converter the unit
runs its electronics off of, the unit's power supply faults and drops
out because this peak load occurs at the same instant as the terribly
low voltage droop......the unit shuts down on low voltage because there
is a battery kill protect IC in it that won't let you run the car
battery down so far you can't start the car just listening to the
stereo....a sort of stupid user protection device.

It won't drop out again after you cycle its power off then on again to
reset it until the next high audio power peak repeats the condition and
trips the battery saver circuit......

Take apart every plug, terminal block, fuse holder between the unit and
the power panel or battery it's connected to.  Clean all the contacts
with emory cloth or just scraping until you shine up the metal then hose
them all down with genuine WD-40, the finest contact cleaner on the
planet.  Restore the connections making sure you have them tightened
down, but NOT OVERTIGHTENED so you break something with those big
meathooks of hands.  pinch the fuse holders a little so it's hard to get
the fuse into them after polishing off the green crap you found
corroding them all up.

You'll probably find some cheap crimp connection all eaten away by the
seawater in the bilge it dropped into.  Replace the wire as well as all
the submerged connections as the water ate all the wire inside the
plastic shield because it had 12VDC on it and acted like a metal plating
machine for months.

IF it has a BREAKER, automatic or manual, and it STILL drops out after
all this terminal cleaning....move the wire to another breaker and test
again.  You can't clean the corroded guts of the breaker so if moving
the wire cured it you need to replace the corroded cheap breaker with
another one.....uncorroded cheap breaker.  Hose the breaker down before
mounting it with WD-40 and it will protect the new breaker for about 5
more years.

Be suspicious of your neighbors at the marina!  They may have gotten fed
up with that loud rap crap coming out of your cockpit speakers and
sabotaged your power connections while you were ashore!  It happens!