Odd problem, sub only works sometimes

[Nevalite 10+ year member]

Hey,

Ok so right now my sub isn't working, but every day or two it will randomly start to work for about 1 minute. While it's working it kind of seems that when I turn up the volume it stops working again, if I don't turn up the volume it will work for about 1-3 minutes but then too it will stop working.

I've tried everything I can think of to get it to work but nothing is changing. Here's some of the stuff I have tried:

-Opened the box and re-wired the sub

-Made a new (better) ground spot

-Tried a new RCA wire

-Tried a different HU

-Tried my ipod hooked directly to the amp via 3.5mm to RCA wire

After each of these attempts it would work for a minute or so as always and then stop. The thing that worked the best was when I switched HUs it worked for a good 5 minutes, I tried to really crank it up (my ears/body missed the bass) and then it stopped working as always.

Now I have sort of concluded that it's either the Amp thats doing something wrong or some sort of electrical problem within the car.

I want to test the RCA wires with a DMM to see if they are constantly giving the amp signal, because if they arn't then its not the amps problem (he cant make something out of nothing)

--- With my DMM set to 10 on the AC scale how many volts should I be seeing? 1v?

If I do see the right amount of volts I will conclude that the amp is the problem.

----------

If I don't see the right amount of volts I will conclude that the problem lies in the HU BUT I know the HU is not to blame (unless they are both broken somehow, pretty unlikely) What could be causing 2 different HUs to not be giving out the right signal?!

That might be the key here...

I really need some input on this, i've been working on this for like 2 months! Thanks

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[mlstrass 5,000+ posts]

Have you checked the remote wire for the amp? Could be shorting out somewhere. Also does the amp shut off when the sub stops working?

 

[Nevalite 10+ year member]

No the green light on the amp stays on all the time, I havent checked it all the way but the amp is staying on so I doubt it's that.

 

[ultimate157 5,000+ posts]

I would point to the sub. Broken/loose tinsel lead.

Pull the sub out and test the resistance of the coil(s)

 

[tcguy85 10+ year member]

put a blanket over it. mad SQL's yo!

 

[Nevalite 10+ year member]

Ultimate157 could you give me some more detailed instructions for that and how I would fix it? I'm sort of new to this and don't really know what you're talking about.

Also could someone give me some details about measuring the RCAs with a DMM, thanks!

 

[tothemax1984]

lol.i know a guy that does that and plugs his box port whole.

 

[ultimate157 5,000+ posts]

Ultimate157 could you give me some more detailed instructions for that and how I would fix it? I'm sort of new to this and don't really know what you're talking about.
Also could someone give me some details about measuring the RCAs with a DMM, thanks!

Pull the sub out of the box, and where you connect the speaker wire, the terminal, is where you measure from with the DMM. Set the DMM to resistance (Ohms, omega symbol) The tinsel lead is the part that goes from the terminals to the coil on the sub. This should read a few tenths of an ohm below the rating of the sub. EG 3.5 to 3.8 for a 4 ohm sub.

If you don't get a reading, its a broken lead.

As for measuring the RCA's... Turn the HU up to ~85% volume, set the DMM to 10v AC. Middle plug is the positive, round outside shield is the ground (negative). You should read what your RCA's are rated for (2v, 4v, 8v, etc)

 

[Nevalite 10+ year member]

Ok I'll go pull the sub out and check this out, but am I putting the DMM on each end of the terminal or one on the terminal and one on the tinsel lead?

Also if this is broken wouldn't it just not work all the time? How do I fix it, can I just solder something back together?

 

[ultimate157 5,000+ posts]

Ok I'll go pull the sub out and check this out, but am I putting the DMM on each end of the terminal or one on the terminal and one on the tinsel lead?
Also if this is broken wouldn't it just not work all the time? How do I fix it, can I just solder something back together?

Sorry, wasn't too clear. One on each of the terminals. And it can be partially broken, leading to sometimes connected (What you're describing)

 

[Nevalite 10+ year member]

ultimate157 I think you may be my hero!!!

I just plugged my DMM, negative where my negative speaker wire was and positive where my positive speaker wire was and it's reading 0hms!!! Its a DVC 4ohm Type-R so I'm assuming it should be reading 4 ohms!!! I've never been so happy to know something is broken!!! lol

Ok how do I fix it? Can I just solder this tinsel lead back on? How do I get access to it on a type-r?

 

[budget76 10+ year member]

I'm going to recommend finding someone local to solder it for you. I had the same problem with my L7. It wouldn't play sometimes, other times it would, then I found out if I pushed the cone a little it would work. My tinsel wire broke as well.

I suggest someone more knowledgeable/experienced doing it, because whatever type of wire they use for the tinsels, my regular spool of solder didn't stick to it. I had to jerry-rig (you could say) to get it to work, and it's very easy to ruin your sub with a hot iron in there.

If you want to do it yourself, there's a good writeup somewhere on here. Search for it

 

[Nevalite 10+ year member]

Bad news, I don't think it's the tinsel lead. I tested the sub with a 9v battery and on both coils it moved...

 

[Nevalite 10+ year member]

Could my battery be causing my problems? It's the regular car battery, never upgraded and the stock alt. If the battery was putting out less than 12v would it stop the amp from powering the sub or something?

 

[budget76 10+ year member]

amp would be going into protect then. Still sounds like the tinsils to me. Do the ohm's test with the sub out of the box, hooked to one coil at a time. Put the 'probes' into the termials, and move the cone in and out. If it drops to 0, bad tinsel.

Could also try running a new set of RCA's. Don't run under the rug and everything, just pull the HU, plug into back, then into amp, and see what happens.

Also, try jumping your remote wire directly to the 12+. Unplug current one, tape it, take a piece of scrap wire, connect to remote and 12+. This will eliminate your remote wire shorting.

all i can think of tonight. good luck