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WAProstar
01-26-2011, 12:40 AM
Does anyone know what this is? This is wired on my stereo's accessory power wire (e.g. the wire that provides power to keep the clock/presets stored even when the ignition is off). There is a 3-amp fuse just upstream of this device. The part was part of the wiring when I bought the boat, but I have no idea if it is original. Boat is '89 Prostar 190. When I bought the boat, the installed stereo was an old cassette AM/FM radio. Didn't look like anything fancy.

Sorry for the crappy, phone quality images...

josepcedwards
01-26-2011, 01:04 AM
FYI. That is not the wire the keeps your clock and presets. That is the yellow wire that does that. Its a voltage capacitor. Is that on your new cd player or left from the old am/fm radio?

JimN
01-26-2011, 04:26 AM
FYI. That is not the wire the keeps your clock and presets. That is the yellow wire that does that. Its a voltage capacitor. Is that on your new cd player or left from the old am/fm radio?

That is not a capacitor, it's a choke filter. It removes noise on the DC voltage that could interfere with the microprocessor's operation. It's probably original to the head unit, but the plastic shell opened.

JimN
01-26-2011, 04:31 AM
Does anyone know what this is? This is wired on my stereo's accessory power wire (e.g. the wire that provides power to keep the clock/presets stored even when the ignition is off). There is a 3-amp fuse just upstream of this device. The part was part of the wiring when I bought the boat, but I have no idea if it is original. Boat is '89 Prostar 190. When I bought the boat, the installed stereo was an old cassette AM/FM radio. Didn't look like anything fancy.

Sorry for the crappy, phone quality images...

If that was spliced in, it wasn't original to the head unit but since the old one had a cassette player, who knows? The boat may have been delivered with out a stereo. Remove it and listen for noise when the motor runs. If there's no noise, leave it out. If you have noise, you'll need to find a better ground point.

The accessory wire- think about it- it's on when the key is in the accessory position, not constantly. The yellow is always hot and is the memory/main power wire. Most manufacturers now use the yellow as the main power supply wire and the accessory is only for enabling the head unit to turn on with the key.

WAProstar
01-26-2011, 02:04 PM
Background: I started digging into the stereo wiring because last summer, the stereo had an annoying problem where it would work fine with the engine off or idling, but under speed, the stereo would go through a power cycle every 30 to 60 seconds. When I looked at the wiring itself, there were some places where I thought I could have an intermittent open circuit (e.g. the bus fuses were not contained in holders).

However, now reading about what this 'choke filter' does, perhaps it is either contributing to the problem OR is not working, but is needed to remove DC noise.

The choke filter is on the original wiring. It was not part of the wiring that came with the new CD player that I installed Fall of 2009. However, it isn't clear if it was soldered on sometime before I owned the boat or has been there from the factory. Who knows?

I was mistaken in my description of the wiring in my original post. When I installed the stereo in 2009, I labeled the wire with this choke filter wire as 'IGN SW ACC or RUN'. So clearly I checked it at that time and it was apparently only hot when the key was in the ACC or RUN position. Unfortunately, I cannot recheck it now as the battery is removed.

So Jim, what you are saying is that the yellow (constant power) wire both maintains memory and likely provides the main power to the stereo? And thus, it should be protected by the larger fuse (10-amps)? The accessory wire is only used to enable the head unit with the key? Therefore, it can be protected by a smaller fuse (currently 3-amps). I put a 10-amp fuse on the main wire because the head unit has a 10-amp fuse built into the head unit, and therefore, no single power wire should require a fuse larger than 10-amps. Do those fuse sizes sound roughly correct?

As long as I have the correct fuses installed and the wiring is good, then I will try it out again this summer and see if the issue is cleared up. If not, then I will remove or replace the choke filter and see if that helps. Thoughts?

Thanks for the responses! As many others have mentioned, this forum is absolutely great for this kind of help. I really appreciate it!

FourFourty
01-26-2011, 02:26 PM
As Jim said- Try it without the filter hooked up. Only thing I wanted to add was to run any and all high current electrical accessories at the same time as you check for alternator noise interference. Sometimes things like electric motors will cause radio noise as well. If your stereo is newer, it will probably have internal filters, and you wont need that Ferrite Core Inductor(filter) anymore...

EarmarkMarine
01-26-2011, 03:52 PM
WAProstar,
I'm trying to think of the reasons why the system would work fine at idle but not at higher RPMs. Certainly you can do no meaningful diagnosis until you have first confirmed the voltage. After that a couple of thoughts.
The DCR on that choke is low enough that its not a voltage problem unless its on a workload line, especially if you have an upgrade source unit with a dc to dc converting power supply. Its doubtful that you need it so remove it for now.
Voltage regulator okay? This could shut down the radio if you're getting too much voltage.
Audio electronics, like amplification, wired to a battery that's temporarily not on line with the alternator?
You're driving the radio harder when underway as compared to at idle and you can't hear the clipping with the competing noise? May have an inordinately low load from a miswired scheme or a speaker with a partially burnt voice coil that is only creating the shutdown as its heating up?
Temporarily unplug all remotes and remote cables from the back of the source unit. Are you pressure washing the transom remote?
If there is water damage within a source unit or amplifier or you have a weak power or ground supply connector it may function at low current levels but manifest suddenly at higher current levels.
A wire harness that is strain relieved a little too tight and pulling on a molex or other connector that is prone to disconnect from vibration or shock.
That's the short list. I hope there's a solution somewhere in there.

David
Earmark Marine

JimN
01-26-2011, 04:25 PM
Background: I started digging into the stereo wiring because last summer, the stereo had an annoying problem where it would work fine with the engine off or idling, but under speed, the stereo would go through a power cycle every 30 to 60 seconds. When I looked at the wiring itself, there were some places where I thought I could have an intermittent open circuit (e.g. the bus fuses were not contained in holders).

However, now reading about what this 'choke filter' does, perhaps it is either contributing to the problem OR is not working, but is needed to remove DC noise.

The choke filter is on the original wiring. It was not part of the wiring that came with the new CD player that I installed Fall of 2009. However, it isn't clear if it was soldered on sometime before I owned the boat or has been there from the factory. Who knows?

I was mistaken in my description of the wiring in my original post. When I installed the stereo in 2009, I labeled the wire with this choke filter wire as 'IGN SW ACC or RUN'. So clearly I checked it at that time and it was apparently only hot when the key was in the ACC or RUN position. Unfortunately, I cannot recheck it now as the battery is removed.

So Jim, what you are saying is that the yellow (constant power) wire both maintains memory and likely provides the main power to the stereo? And thus, it should be protected by the larger fuse (10-amps)? The accessory wire is only used to enable the head unit with the key? Therefore, it can be protected by a smaller fuse (currently 3-amps). I put a 10-amp fuse on the main wire because the head unit has a 10-amp fuse built into the head unit, and therefore, no single power wire should require a fuse larger than 10-amps. Do those fuse sizes sound roughly correct?

As long as I have the correct fuses installed and the wiring is good, then I will try it out again this summer and see if the issue is cleared up. If not, then I will remove or replace the choke filter and see if that helps. Thoughts?

Thanks for the responses! As many others have mentioned, this forum is absolutely great for this kind of help. I really appreciate it!

Which wire has the larger fuse depends on the head unit. Regardless, if it's a new one with high power, the factory power and ground wires may not be adequate. If the head unit draws too much current, it will have several problems, including a shortened life for the head unit and speakers. Some head units have a 15A fuse inline, so it's not a safe assumption that it shouldn't be larger than 10A. That filter won't help a high power head unit and may actually limit the current available to it, so I would remove it. If you have noise, it's usually inadequate wire gauge, terminations and/or a bad ground. If you have an amp in the system, bad grounding will definitely cause noise and that filter will do nothing to help.

The power cycling could have been several things, including overheating. Low voltage to the head unit will cause it to run hot (inefficiently), or if the ground/power connection integrity is bad, it will cause problems, too. If you make connections, soldering and heat-shrink is best if done properly, followed by Heat N Seal butt splices. These have glue that melts when the sleeve is heated and it forms a waterproof seal. Some have solder inside that melts at an extremely low temperature but if the wires are clean and dry, it may not be necessary.

When in doubt, read the manual for the head unit- it will tell you what gauge wire is needed, although I would increase it by at least one gauge in a boat, because of the length of the wire runs. If you have/add an amplifier, you can use the ignition/accessory lead to feed the head unit (as long as it's adequate) but if the wire is too small, you're better off using that red wire to latch a relay that's connected to power with a heavier wire.


The high RPM issue makes me wonder if it's a loose connection or an alternator belt that's loose. Next time you put the battery in the boat, make sure you clean the cable clamps and battery posts first. If it solves the problem, you know where it was and can use that for future reference. If it still does this, turn the stereo on and wiggle the power and ground wires at every connection and as Earmark says, make sure the wires aren't pulling on the molex plug(s).

If the radio is mounted at the face and doesn't have a strap at the rear, put one on it. That can cause this kind of problem, too.