Stereo Died

[AE86less]

I've been mucking around with the sub in my GX71.

I have been running a DVC sub off a 2 channel amp until I recently found that one of the voice coils wasn't going at all.

I bridged the amp and put in a SVC sub. First track I played was 'Tarantula' and the moment it got to the bass drop the entire system died. No sound from the speakers, HU is dead, amp has no power light. I've checked all the fuses and have found nothing amiss there.

Any clues?

[THA SHZ]

have you checked all your earthings sam ?

[DeeCee]

As said previously, check wiring/terminations.
Maybe dome light fuse in engine bay fusebox. If it was strictly amp, then ground. If hu is not coming on then a fuse may have blown up the front.

Also check if you can start the car. Playing around can cause current drop and make you have to jump the car.

[AE86less]

Other than a dead VC the other sub did run with no issues like this.

The earths seem to be ok. The HU earths into the factory earth wire on the loom (I assume it's an earth wire, auto sparky put it there.. I guess I need to test that?). The amp is earthed fine too.

The car starts and runs fine.

All the fuses in the engine bay are fine. The Dome fuse is in the kick panel but is also fine. The switched power for the stereo comes from the clock which is still running.

I'm very confuzzled

[DeeCee]

you confuzzled? I'm confuzzled!
Can you pull the headunit and access the wiring? if so, disconnect the RCA(s) to the amplifier(s)
Speakers are running off the headunit of sep amp?

how is the headunit connect to the factory loom? loom adaptors, choc block strip or solder/twist/tape method?

[AE86less]

The speakers are running off the HU.

I'll try the RCA's in a moment. Edit* No change.

The HU isn't really connected to the factory loom. It's earthed to the loom using some sort of connector thingo that taps it into an existing wire. The rest of the stereo loom is made up. Constant power coming through a wire straight from the battery (with fuse, which is fine), switched power from the clock, new speaker wire has been run by a previous owner. All joins have used choco blocks.

IMO it seemed like the stereo died in response to the bass drop in the song. It didn't sound like the sub was actually playing though.

[DeeCee]

how adept at you in playing with wiring?

If battery is low in power and the bass drop causes the amp into protect due to voltage drop, then generally a protection circuit will shield any attached wiring from spiking or back EMP.

If something is shorting out, then that can cause a spike to travel back through the RCAs to the headunit, which is why i asked you to remove RCAs if there is still a short somewhere on the amp.

1) does the headunit have a fuse on it? Normally located on back of headunit, sometimes under the loom plug
2) what is the unit model? basically what are you running in the car equipment wise
3) you say the headunit has been grounded to factory, but uses a seperate fused power. Try to ground the headunit to bare metal, normally the metal frame between the dash cross member and the trans tunnel - why i asked you if you are adept at wiring.

basically need to isolate the headunit and its power, turn on and ground to see if the unit is actually functioning. Potentially it could be an internal fuse, but that is very rare with most HU's have external fusing on the body of the hu chassis or on the power line.

[AE86less]

Thanks for your help DeeCee, I really appreciate it

I should hope that the battery is good, it's fairly new (less than 6 months).

I've checked the fuse on the HU; it's still ok.

I don't know which HU it is. It's a mid-range Pioneer unit, from either the 08 or 09 range. The amp is a old-ish Lanzar Viberant 2ch and the new sub is a Clarion 10".

I can manage that sort of wiring, I'll try it out after it stops raining again. If it is a fault with the HU, what's likely to have caused it? Power spike?

[DeeCee]

Hmm.. well its not the pico fuse inside the unit as that would just give noise (generally)

Generally its a wiring fault that will cause the unit to fail, therefore a short or voltage spike that kills the unit.

In this case, my tendency would be to pull the unit and test the unit turns on. Basically ground the unit and wire 12V constant and 12V ignition turn on together and test if the unit turns on or not. If it doesn't then there is a fault with the unit. You got a warrenty on it?

[MAGN1T]

The speaker would have died for the usual reason (too low a power rating). That in turn blows the output stage of the amp. That in turn blows the input fuse of the amp. The head unit might be taking it's power from the amp.
Fault finding is a no brainer with a voltmeter, if you don't have a voltmeter you shouldn't even be playing with wires.

Steve

[AE86less]

I do have a multimeter, and while I've never claimed to be anything other than electronically retarded I do have the nouse to be able to wire in a stereo.

The sub and amp are actually pretty well matched. They have the same max power rating and the amp has a slightly lower rms rating. The fuse on the amp is still intact.

[Adamal]

Given the way its happened, I'd say your HU is cooked. Just check theres power going into it.

[AE86less]

I will today.

If it is cooked I don't want to go out and buy another just for that to get pwned?

[DeeCee]

ideally you'd test all your equipment before installing the new headunit to ensure that there are no issues. Pretty simple