kz
Member
Registered: 9th Aug 02
Location: Southend, Essex Drives: Mini Cooper S
User status: Offline
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Ever since I added a sub/amp to my MINI, it wasn't quite right. I had interference which sounded really bad when the car was off or at low volume... I mean, it was always there but when you turn it up the problem goes away right 
Anyway, I was told the most likely cause was a bad earth. Checked on the amp first but all was good. Next up checked behind the headunit. Now the earth had been plumbed straight into the harness converter which probably isn't the best way to go. So I got a another earth and extended it off to the chassis. Turned the headunit and and no interference!  happy days. Turned the car on, and... smoke started pouring out from the headunit. Quickly turned it off and eventually checked the fuse, which had blown. Also noticed that it was 10A when it should be 15A, so replaced with the right one. Tried again and there was still smoke coming out!
Getting kind of annoyed at this point because it just doesn't make any sense. However I thought I'd just put it back to how it was for the time being and try and figure it out another time. So I did that turned the car on to drive away again and, yup, more fucking smoke. What the hell? It was working fine like this before. Checked no wires were shorting out or anything and nope everything's fine. The only thing I left different was having the 15A fuse in there rather than the 10A but can't see that making a difference when it's meant to be 15A in the first place?
So now I have no sounds at all  any ideas? I'm dubious to just 'try' things out without knowing for sure as don't want smoke pouring out when I'm in a situation I can't do anything about it.
Bah.
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Ellis
Member
Registered: 11th Sep 07
Location: Aberdeenshire
User status: Offline
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You shouldn't need to make any alterations to the earth at the headunit in my experience. 12V from battery to amp with in line fuse, amp earthed to boot floor or nearest available place. Remote cable feed from head unit to amp. Something fishy going on here.
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DaveyLC
Member
Registered: 8th Oct 08
Location: Berkshire
User status: Offline
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If the earth isn't good enough at amp it will ground through the RCA leads and cause all sorts of grief..
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kz
Member
Registered: 9th Aug 02
Location: Southend, Essex Drives: Mini Cooper S
User status: Offline
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I'm talking about the headunit though... the amp side of things is fine.
I've had this same setup in 9 different cars! Never had a problem, but have always earthed headunit to chassis (as recommended by Alpine) but someone else done this install for me and he didn't do that. To be honest I think he just bodged it because it saved time, which ironically is the only reason I didn't do it myself in the first place!
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DaveyLC
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Registered: 8th Oct 08
Location: Berkshire
User status: Offline
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It will be earthed through the loom.. The -12v wire doesn't just go all the way to the battery  it will go to the closest earth point on the chassis.. More chance that the amp isn't earthed properly..
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Tiger
Member
Registered: 12th Jun 01
Location: Leicestershire Drives:Astra VXR
User status: Offline
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Sounds like a burnt out / dying power supply in head unit or a big resistor on the PCB.
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kz
Member
Registered: 9th Aug 02
Location: Southend, Essex Drives: Mini Cooper S
User status: Offline
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I had the amp earthed directly to the battery negative because the battery's in the boot... then tried to chassis and it was the same either way.
Anyway, remembered I still had the standard stereo so chucked that in tonight; worked perfectly.
Thought I'd literally just put the ISO block on to the Alpine unit... so exactly what was on the standard headunit. Not even connecting the power. Still started smoking!
So it's got to be something in the harness converter or unit itself. I did feel the yellow cable was a bit hot compared to the rest. The manual says it needs to be wired to the battery... which it isn't, but, I've had this headunit through 9 cars now and I've never actually done that, and it's been fine on my previous 8 cars lol.
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