ARC Audio amp shutting down

[Fman]

I have an ARC Audio amp powering my inboat speakers and subwoofer. Never has missed a beat up until last week. It will shut down and I loose all volume to inboat speakers and subwoofer. When I look at the amp there is a red light flashing. I am not playing the speakers any louder than I have in the past. It will then turn back on later in the day, work for a bit, then the same problem occurs. Tower speakers still work fine when this happens. There is no pattern of when it happens. I checked the RCA cables in the ws 420, amps, and they appear to be fine. We were listening to the stereo on a very low volume the other day, started to board and within 20 seconds the volume cut out.

Anyone have any suggestions on what I should be looking for? I called my installer and he said to count the blinks on the red light to help with diagnostics. I know there are some very knowledgeable stereo users on this site and wanted to get some feedback.

Thanks for any input...

[Bobby Light]

Since that amp is probably drawing the most current my guess would be low battery or thermal. Count those blinks it will tell you whats going on with it.

[nyryan2001]

Was it hot? Did it come back on after some time?

What amp and how do you have it wired?

[liljohn]

Low voltage Would be my guess. Had this happen once when bank one and two got switched around.

[Roster man]

Arc has a $150 repair or replace service so consider that if other avenues dont pan out

[Murphy8166]

It is 75 per hour for repair at Arc and they have never had an amp take over 2 hours to repair. It is not a flat $150, I just went thru this.

Grab yourself a voltmeter and give Brad or Theo a call at Arc Audio. They will gladly spend 20 minutes with you over the phone to help you diagnose your exact problem. Since you have a dual amp shutdown, I would imagine you have a voltage issue either at the power, ground or remote wire.

I just had 300.4 crap out on me and we were able to diagnose the problem. The nice thing about Arc is that they know amps can fail and they won't try to blame on other components in your stereo system in an effort to "pass the buck"

[Fman]

There is only one amp shutting down, the tower speakers are still working. My installer Ben has been great, its still under warranty but he needs to know the flashing light sequences to diagnose the problem. We are going out this evening so I am sure it will happen again. He said if its a defective amp he would install a new one and send out the old for repair.

Could a backpack stored in the locker area the amps are mounted in possibly changed a setting by hitting a button? I usually make sure the amps have enough space around them for cooling reasons, but I noticed some buttons on the amps. Nit sure if one was depressed or pressed if it woukd cause this to happen?

[shawndoggy]

There are probably two buttons, each of which would control the crossover frequency range for the front and rear channels of the amp. If you pushed them it would set the xover point 10x higher. Your cabin speakers would sound like they lost their midbass and your sub would sound muddy (and maybe you could hear it trying to reproduce actual music).

In short it would make your system sound pretty weird if you had pushed one or both xover buttons.

[Bobby Light]

A backpack leaning against the amp could cause thermal issues.

[Earmark Marine]

Depending on the series of Arc Audio amplifier it may be covered by a thin shroud which really isn't a heatsink. The heatsink may be concealed internally and fan-cooled. In this case, something leaning against the exterior shroud should not significantly impact the thermal stability. But, something blocking the vented end caps could definitely have a big impact. It's also helpful to slightly elevate this particular amplifier off the mounting surface. A fan-cooled amplifier is usually more dependent on the fan so verify that the fan is operational.

David

[Fman]

Ok. Did it again this evening, no backpacks or anything against amp... Red light showing 3 continous blinks, pause, one blink...then it repeats itself.

Any ideas? If I power off head unit and turn back on it seems to work again for a short period of time... When it works everything sounds great.

Edited July 7, 2012 by Fman

[shawndoggy]

http://www.arcaudio.com/pdfs/product-manuals/amplifiers/ks-series/KS300-600_amp_manual.pdf

looks like that's a repeated short code. Sounds like you probably might want to consider figuring out whether you have a short on your speaker wires.

[Fman]

Going to start process of elimination, disconnect sub, then if that does not work, speakers...... Bummer, hopefully I can figure this out soon....thanks for the feedback.

[Murphy8166]

This is the exact same problem that I had with my KS300.4 - it ended up blowing a couple output transistors on the rear channel.

The first place to test would be beyond the the amp. An exposed speaker wire or even on cooper strand touching ground or something it shouldn't can do it as well.

If you can get you hands on some new speaker wire - run a jumper and see if that does anything.

[Earmark Marine]

You would usually begin with measurements of in the boat wiring and speakers but that is not always enough.

Substituting one speaker at a time with a new lead wire and new speaker may be essential in diagnosing the real issue. Here is why. If a speaker voice coil is on the edge (with a burnt enamel coating that normally serves to insulate the small windings) then it can read fine with the low current of a multimeter but behave very differently once heated up by the amplifier.

If you suspect a damaged output device then this is usually easy to detect while the amplifier is still in the boat. With the topology of most Arc Audio amplifiers, the RCA shield ground will be common with the speaker output ground (keeping in mind that one channel is inverted to provide for bridging). That references 'above' the primary or power supply ground by a certain resistance. The manufacturer can tell you what the resistance value should read and what is a tolerable variation between the primary ground and speaker output ground for your particular amplifier. You can do the same measurement between the RCA and speaker output grounds and also on the positive speaker output to ground. A damaged output transistor usually will be revealed with a simple multimeter and without looking internally.

David

[Fman]

I have one problem, we are literally riding every day for the next couple weeks so my time is limited. My installer recommended to start by disconnecting the sub RCA, run it, see what happens, then if it continues to pull the inboat speaker RCA cables. I assume this will let us know if it us coming from the sub or speakers.

It's a little bizzare to me that it works for awhile then shuts off. I would think if there was a short it would immediately show up as soon as the amp turned on?

Thanks for all the feedback, I am nit a stereo guru, so any help is always appreciated.

[Earmark Marine]

An easy solution would be to ask your installer if he and his multimeter would like to go wakeboarding.

[nyryan2001]

IS THE AMP HOT WHEN IT SHUTS OFF ???????

[Fman]

It technically does not shut off, it goes into the trouble mode...and no, it does not feel hot.

[JuJu]

I am having the same issue with my new 2018 22MXZ. Except it’s my tower speakers.  I added two icon 8s under the rev 8s on the tower and they work great until we start moving on the water. Then they cut out. The fault code on the amplifier we get is six red flashes to one. Does anyone know what this means?

Thanks!

 

[MLA]

Sounds like chnl short. Wire pinched or chaffed on tower.