Intermittent Subwoofer (Andy Mac installed 6" JL Audio) ***Help Needed Please***

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Hello.

Had the system installed by the man himself for around 18 months. Worked perfect until this week...

Every now+ then the sub works in my 2002 BAM 8L. Sometime it will work & other times, not. No reason why I can make out.

Could somebody please diagnose the issue(s).


I'm thinking it could be...

Check the fuse isn't dirty/ replace it anyway? *Which 1 is it for the rear speakers on the relay? Number 42? 20A? Radio?*
Ground cable for the amp? *I will be taking apart the rear passenger side + having a look at the ground/ ensuring it's connecting 100% and re-do the ground connection*
Amp is packing up & will need replacing altogether? *Would it be a 150W RMS (bridged) 2 channel?*
Headunit issues?



Thanks guys.

Joe
 
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Hi Joe
If it's an intermittant fault then it won't be a fuse and unlikely to be the amp, it has to be a wiring issue - something has worked loose, probably on the adapter loom. Did anything happen when it stopped working? Does it come back on just randomly or when it warms up, or when it's cold. The alpine amp has a thermal cut off, so if it overheats it will shut down.
 
Didn't you have to use a GLI to get rid of some alternator whine? My money would be on that failing for some reason
 
Hi mate. Yeah, I did use the GLI and to my knowledge, its not the same issue. The GLI was used in conjunction with the "whine" on idle/ driving.

This fault just doesn't send any power to the sub atall.

Then, randomly, it will come back on. I think your right - it could be the heat that getting to the amp. However, this morning straight from cold circa 9am... Still nothing.

Hmmm.
 
No I meant if the GLI has an intermittent fault it will cut the feed to the amp. Take the GLI out and see if the problem goes away.
 
Hi Andy, Sorry for the extremly late reply.

IIRC you sent me a guide/ "How to" in relation to dismantling the passenger side rear to get at the amp/ GLI to check.

Granted it was over a year ago now since I last had a look in there because as you rightly previously said, I had a problem with the rear lights also as you had to move/ re-posision the brown earth cable.


I've had a look on the "Dizzy the dog" link you had sent me and I cant seem to find it or the link has expired.

Could you re-host it + I'll report my findings on this A.S.A.P


Thanks bud.

Joe
 
audi upgrades
Ok soooo... Had a look this afters.

Carefully undone everything and here's where we are.

1) The Amp "green light" is always on & doesn't display a warning light nor flickering when music is playing or ignition is turned over.
2) The GLI has been replaced by a new 1, and still, not a sausage.
3) The 30A fuse on the amp (The green one you can pull out & replace has also been done) again - No Bass.
4) I'm stuck. :keule:


The only thing left is ground wire cluster related near-by the rear seat belt harness?


Cheers Andy.

Joe
 
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I would try it without the GLI at all just to ensure the new one isn't faulty (long shot I know)
Then it's just an elimination process.
Check the impedance of the sub (where it connects to the amp) with a multimeter set to its lowest ohm setting (usually 200 ohms). Disconnect the sub connections at the amp and measure the impedance across the 2 wires, should be 4 ohms. If it is open circuit then chances are you've blown the voice coil, remove the sub from the enclosure and do the same measurement directly across it's terminals. If you get the same result then the sub is fried and you'll need a new one.
If that checks out OK then you need to check the amp. Connect a spare speaker to one of the channel outputs (ch1 or ch2). Switch the low pass filter to "off" and see if it plays, you can use the rear speaker in the car if you don't have any others, but turn the gain down first. Then do the same for the other channel. If you get nothing playing then it has to be either the amp or the input wiring. You can drive the amp off an iPhone or mp3 player headphone socket if you have a 3.5mm jack to RCA adapter.
Or I can swap the amp for you for the cost of postage.
 
Hi Andy. Internets been dodgy atm / sorry for the late reply.

As instructed, GLI has been replaced by a new one. Still... No bass plugged / unplugged & still no bass... So that's out of the equation.


Can I start the elimination process in motion by using a spare sub / amp I have stashed in the shed?

I have an early 2000w RMS Orion H2 spare, Also a monoblock which is in perfect working order that can be utilised for this test.


Question: Could I take the Alpine out (for the proposed test), wire up the monoblock, *turn everything low most importantly the gain + see if it sends bass to the rear AMSS Sub?* and, then reverse this with my orion sub to the Alpine to check if either's knackered?

I haven't got a Multimeter otherwise, It'd be a simple jobbie to do. I will (obviously with your knowledge & guidance) get it sorted soon-ish.


Thanks pal.
 
Hi Andy, At the end of everything. I believe the sub's gone kaputt.

I had ripped everything out / even the box + amplifier to test as per previous above.

The intermittent-ness of the sub working... Is a voice coil failure backed up by an independent I.C.E. dealer / JL Supplier suspicion.

He hasn't had it opened up to view the coils /innards, however on a bench and "its getting 4-5 Ohms on both sides?" When you turn on the system, it plays, then cuts all base. Only when you lightly press the cone (inwards) to make a connection on the coil, it starts up again. Then goes silent again. Had the amp on the Orion H2 & this clarifies (the 6.5 JL Sub as the issue) as this plays without issues throughout 5-10 mins of normal music without disruption.


I did notice however the amp was turned up to full on the gain. Whether or not this was an issue from the install & started the wheels in motion we'll never no. Was there ever a manufactures guarantee from date of install or not?

Annoyed is not as this was never turned up loud to blow it, but hey ho. Never mind. I'll get saving.


Thanks for your help Andy.
 
They come with a 1 year warranty, and you're way past that as it was installed in April 2011
The amp gain is correct, the pre-out signal is pretty puny from the Audi HU so it has to be near max on the amp.
 
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