I have an aftermarket sub and amp in my cobalt that I just bought from somone a few weeks ago.

Everything worked fine, until one day I realized that the sub isnt really bumping anymore. I then realized the amp wasnt working anymore, because the graphics on it wernt lit up like they normally were. But i did see that the sub had a green light on. So I am guessing the amp is messed up.

I had a friend of mine check it out since he knows alot more than I do about audio systems, and he said that all the power cords and grounds seem to be intact, and that unless there is a burnt fuse inside the amp, he has no idea whats wrong.

We also noticed that the capacitor that is attatched to the sub has a small digital display, that shows 0.0 I dont know if that has anything to do with it.

Any ideas? I know it isnt that easy to diagnose with such limited info, but any suggestions would be great.

Thanks!

 

you have the cap. in between the amp and sub. or do you have the cap between the battery and amp?

 

it seems like the capacitor is inbetween the battery and the amp.

it seems like the wires go from the battery to the capacitor, then to the amp.

but the capacitor is mounted onto the sub.


So maybe it is from the battery to the cap. to the sub to the amp.

 

take out the cap first. just connect the battery to the amp see if that works cause since you have a cap. the cap. would have blowen first. what are you runnin?

 

i'm not sure what you mean by what am I running.

Like, how many watts?


I dont know off the top of my head(i didnt install it, the previous owner did), but maybe its like 2400 watts? maybe i just made that number up, but i think that is what it says on the amp.

 

no i mean what amp and what cap. but take the cap out and try it with out it, that might be your weak link, also do you have an inline fuse?

 

Hmm...

I'm not sure how many amps I get, or what my cap. is, but I will find out tomorrow.

I am pretty out of my element here because I have never done any audio work before, and the guy I bought if from did everything to it before i got it. He seemed to do a pretty good job though. My friend that checked it out for me said that maybe I was bumping the bass too loud, and then hit like 7000rpm, and just fried the amp.

Tomorrow i will check out the info you just asked me, and try connecting the batt directly to the amp w/o the cap. and see what happens.

Thanks for your help diablo!! I will get back to you soon for more help.


Thanks again!!

 

no problem, just let me know what happens

 

If your cap is reading 0.0 your cap could be dead or it could have disscharged compleatly. For some reason alot of caps say that you have to trickle charge them when they are first installed (usually with a lightbulb or something).

So I would agree take out your cap and hook the amp directly to the battery. Atleast this way you can narrow it down a bit more. Eliminate problems little by little.

 

if you dont know if your cap is between your amp and sub or your batt to amp or if you have a inline fuse you should
pay someone else to check it and see if they will give you a crash course on car audio.

But if it is hooked up right get a multimeter and see what you have at the end of your should be red + or just check both find one that has power if none check your fuse and connections at batt if all is good take cap out

 

sounds like the fuse between your cap and battery is blown, or one of the fuses in the side of your amp is blown. check those

 

They do this because if you hook them directly to the battery the sheer amount of electricity that flows into it when charging will cause a big spark and possibly weld the wire right to the capacitor.

 

I don't mean to be an ass here, but does this guy know how to install a car stereo?
Seriously, if you don't know how the basic components work, what they do, or what they are... you should be finding a professional to service the stereo for you.
Take it to a stereo shop... probably where you bought it... OR... find a friend who knows what the hell is going on in your trunk!

 

QFT!

 

I'm not sure if your happy about what i said... or pissed off...

If your pissed off ->
Did i offend you or something?
I was talking about the guy who started the thread... you know, the guy with the problem....

If not -> ignore above statement... on with the topic....

 

No, I do not know much about what is going on in my trunk. But I didn't think there would be any harm in asking for help online.

And I did bring it to a friend that has installed many systems in his cars and others, but he still only knows the basics. He said that he is a little out of his element because he doesn't know much about capacitors, so we were both going to see if anyone had any ideas online.

I was trying to avoid paying someone to look at it, since I am considering taking it out altogether anyways. It seems like the stock sub is a decent one, and bass isn't really that important to me anyways. But I figured I would try to get it up an running again before I decide whether to keep it or not.

I'll try connecting the battery straight to the amp and see if I get any results. If that doesn't work, maybe i'll see a proffesional, or just sell it to a friend altogether..

Thanks to everyone that provided help. I appreciate it.

 

i took a look in TKolb's trunk, and this is what is goin on:

power wire (4g) from battery to distributing box. there is an inline fuse in this line, and it is intact.
distributing box splits 4g wire to 4x 8g wires... two run to the 1 fared cap., and 2 run to the amp(rockford fosgate punch series 2400watt @ 2 channels). all connections are intact.
cap has a 4g ground, amp has 2x 8g grounds, all connections intact.
remote wire from head unit runs to cap. and then to amp... connections intact, when car is on the cap has a green light on top that comes on, and it reads 0.00....
amp should have power and ground even with a dead cap

this is not a newly installed setup.. i assume the cap is dead because of the read out (0.00)
do you think the amp is fried also??? it has power directly from the battery, a good ground, and power from the remote line...
the only thing i can think of is the possibility that a sub wire in the box has disconnected and is touching the other... causing the amp to short

any help is appreciated

 

QTF (in this case)= Quoted for Truth?



@ jaguarshark:
Where are all of the ground wires connected? If there was paint on the surface is the paint completely stripped off?

That fostgate amp is going to be a pretty well made amp. I would guess it could take a bit of punishment before it dies. If it is the p8002 like I am guessing then it would have some pretty good protection, like thermal overload protection, NOMAD intelligent protection circuitry, and 150 amp fuses built into the amp.

How do you have the amp wired up? If you have it bridged down to one channle it is only stable at 4 ohms. So that could cause the amp to shut off. Some amps may let you play them for a while if you have them at a lower impedance than they take. Other amps will not ever turn on.

 

Yeah, like mesatrin said, I would look at the grounds. If the cap is reading 0.00 volts, and the grounds are in the same location as the amps, it's likely the amps aren't getting any voltage either.

Try using a digital multimeter or test light to test for voltage at the cap and amp. Put one lead on the power wire, and the other at an exposed metal surface for ground.

Also, have you verified the 4g connection to the battery, or do you just see it coming from the battery into the distro. block? Maybe it fell off.....

 

....in this setup, the cap is in parallel... basically it is acting like a second battery to the system.
If the cap dies, the amp will still run.... (at least it should..)

Besides the obvious grounding issues, i would say to check the following (unless you already have.... i can't really understand half of the stuff in the explainations)
- the remote turn on wire (you never know.. )
- check the sub on different system

The reason i say check the sub on a different amp is that if you were 'bumping' the sub too hard, and it was improperly set... the sub may have fried the internals to the point that it fused the sub internally, creating a dead short... this would cause the amp to turn off on a current protection, and cause the amp to not suck (very much) power, thereofore the cap would regester as no power demand.

Just my 2cents


BTW... i was assuming that QFT meant quit fuking talking.... sorry if i lashed out...

 

ok im going to assume your running the 801s but it doesnt matter much... anyway that is not the correct way of hooking up a cap and im pretty sure he didnt charge it either. So your best bet is to go to a shop and get them to fix it up for you. but if you want to try and do it yourself.... disconnect the cap and the d-block for one amp you do not need a d block and you can do it just fine with the cap there.... if that d-block was fused and was the only fuse from the bat-cap your going to want to buy a 4g fuse holder... your going to then charge the cap like the instructions that came with it says. Hook up the cap using the 4g wire and some ring terminals your then going to hook the cap to the amp with 2 runs of 8g power... you should be able to use your current grounds (but the way this was hooked up they might be **** too), if not run new grounds but make sure to always have the ground ran b4 running power

 

oh ya remote wire needs to be ran direct from hu to amp

 

no no, quoted for the truth is what i meant.
no man its all good, it was my fault. I was saying that what u said was absolutely true, too many kids putting in stereos and not knowing how things work> if you dont know what u are doing,then take it to a shop and pay someone who knows whats going on, that way if they mess it up they will fix it.

 

Glad we're both on the same page...

 

please dont confuse me for the guy who installed this, im just the guy trying to fix it....

remote from hu to amp? i only question this cause the cap has a remote input spot... and with out it, the green light in the cap doesnt come on.... and also because i ran fine this way for a year or so

grounds are in seperate locations, but are on painted surfaces.... i thought of this as a problem, but figured them to be okay cause the system has worked for a year this way... they are still on tight.

power wire has been checked at the battery, and it is connected well

the sub is wired like so:
the 6*9s were tapped into and ran into the high input on the amp, with the lp filter on...
the sub is a six sided sub(cant remember brand) and is only ran off the right sub output... not bridged

thanks for the info... next time i can get Travo over i will get out the multimeter, and also check the system with another sub

**unplugging both speaker wires to the sub, at the amp, would allow the amp to come on (and light its logo) without even bringing other subs into the picture... RIGHT?
isnt that a logical way to test if our problem is in the sub?
thx