12 replies to this topic

[Tornado99]

My pioneer headunit starting making a few crackles & pops on recent drive, then later all sound shut down. Unit powers up fine, all functions are there. Just no sound out the speakers, no matter which source I select (tuner/CD/AUX (which I have a BT transmitter/receiver on). Unit is connected to a good sized amp in the boot...which is coming on with the HU. I've checked fuses on the HU rear surface and the amp, look good. Tried disconnecting everything on the HU to fully power out/reset it. Same issue.

 

Any tips from those with experience on troubleshooting these things? I read on-line that a speaker wire shorting to ground can knock out all speakers until corrected. 

Edited by Tornado99, 28 February 2022 - 02:26 AM.

[stuart bowes]

set voltmeter to continuity testing, touch probes together to check it's beeping, put one probe on ground, the other one on each speaker wire output from the amp in turn (best to disconnect from amp first one by one because sometimes you can get continuity through the amp's components which is misleading)

 

if you get a buzz on any of the wires then you know that it's an earth short.

 

I assume you've checked that all your terminals on the amp are nipped up tight because they can rattle loose especially in very bouncy cars with stiff suspension like the mini

 

it's unlikely that all / both speakers have died all at the same time, and if it was a fuse you'd notice a lack of power at the amp or the head unit, so it pretty much has to be wiring i would guess

[Quinlan minor]

. I've checked fuses on the HU rear surface and the amp, look good.

 

Any tips from those with experience on troubleshooting these things? 

Don't rely on looking, where fuses are concerned.

Electricity is invisible, until it turns to smoke.

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[stuart bowes]

not necessarily..

 

but you make a good point about fuses in general

 

I was assuming he meant the amp power light was on, and headunits are usually pretty well lit up like a christmas tree when there's power

 

actually there is one thing you could check for, my sub amp has a 'protect' LED, when lit up the amp has shut down due to a fault, once in my case it was actually caused by the speaker wires shorting to each other.  (2x12's sharing 1500w tends to make things move around a bit.. the wiring is better isolated now)

Edited by stuart bowes, 28 February 2022 - 03:18 PM.

[Tornado99]

Good suggestions for testing the amp outputs. This mini came to me with this system already installed with two dash speakers, two larger parcel shelf speakers and four under rear seat speakers. All powered from the large-ish PlanetAudio amp bolted onto boot bulkhead.
Is it common to have one output grounding to cause all speakers to go quite? So sort of amp failsafe function?

[stuart bowes]

I'm just guessing in all honesty but yes that sounds about right.. I wouldn't be surprised if it just did a total shutdown

 

not necessarily a grounding, could be a short between cables, or even something metallic in the boot got wedged in between contacts?! who knows.. I've wrapped all my terminals in gaffa for this very reason

Edited by stuart bowes, 01 March 2022 - 10:25 AM.

[Tornado99]

Checked things over yesterday. I confirmed the PlanetAudio B B 4.150 has a protection LED and it is lit red when powered up. Checked/tested two mini fuses on the amp, good. The big fuse at batt positive also good (units is powered up).
Went through all the speaker lines, removing from amp one by one and checking for continuity to body ground via multimeter. No grounding found. Also checked the rca jacks into amp one by one, all showed no ground connection.

Where to go from here?

[Quinlan minor]

Tornado99, on 01 Mar 2022 - 6:49 PM, said:

Where to go from here?

Connect speakers direct to head unit to see if the amp is the problem.

Edited by Quinlan minor, 01 March 2022 - 09:11 PM.

[bpirie1000]

Is the head unit a face off type?

Make sure conections are all good there if so...

How is the amp feed connected to the head unit.

[Tornado99]

I surrendered and took it into a car audio shop. They tested everything again and report the amp itself is the issue, something has failed within. 

 

So, now I need to consider how best to proceed. 

 

There are eight speakers in the car (two fronts, four under rear seat and two more under parcel shelf (which I think are a bit larger than the 6 other units, woofers?). Amp was 4 channel, 300w....parcel shelf speakers were on the CH3 +ve & CH4 -ve connections, in what I think is a bridged setup.

 

Do I just look for any other kind of 4 channel amp or should I be changing the setup to something else? Not wanting top of the line stuff...just something that handles the speakers I have to good effect. 

[stuart bowes]

did you check for continuity between +and- cables as well as from each cable to ground.  could still be a short in wiring or at the speaker connections maybe

 

amps do die sometimes for various reasons, overheating, overuse, wrong wattages and ohmage ratings not suitable etc etc, I've gone through a few myself

 

I would spend some time looking at exactly what speakers you have (watts and ohms) seeing which ones you really do need, and planning out from there what amp is suitable

 

also look at how those 4 under the seat are wired together, parallel or series, because that affects the ohms rating and could be drawing more than the amp can provide and causing the issue

 

may be an idea to speak to that shop you went to for advice on that?

 

probably want to budget a good £200 or so.. don't go for something really cheap which may just fail again and be a false economy

Edited by stuart bowes, 02 March 2022 - 11:59 AM.

[stuart bowes]

300w is a) probably an optimistic total (they usually exaggerate) and b) seems a little underpowered for that many speakers. 

 

Even if we accept the 300w at face value basic maths gives you 37.5w per speaker which is a bit minmial.  the bridging makes things a bit more complicated but still..

 

I'm guessing it would have been turned up pretty much to the max on the amp

Really you want an amp that is over powered and have it set to like 70-80% of its potential at most

Edited by stuart bowes, 02 March 2022 - 11:58 AM.

[bpirie1000]

Just go back to the head unit outut until you can hook the amp up again.