buzzing w/ engine off

[danz24 10+ year member]

hey i am getting a buzzing noise when my speakers are connected to the amplifier. It only happens when the ignition is on but when it is off the buzzing noise is replaced with staticy noises. it is not alternator whine because it happens when the engine is off.

i checked the grouund of amp (kaption 50.4), and headunit (pioneer 7600)

i checked teh RCa and tried to ground it too

the store checked the amp and it is ok

the power wires are away from speaker and rca wires

any other ideas on what to do?? i am stumped..thanks in advance

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[Ignatowski 5,000+ posts]

thats an easy one......

your HU is cooked. Crazy? Not really..

Pioneer's have an internal ground that often shorts out when an RCA plug is interrupted while the power is still connected,its really lame and exactly what happened to my 7600.

After further investigation just like your doing right now I found out just how common a failure it was,angerly

I tossed it in the can and never bought Pioneer again,this never happens with any other brand I know of.

If you have a full warranty they will repair it.

Symptoms: NOISE,crazy noise weather the car is on or off,exaggerated whines even when the car is off.

Thumps and buzzing etc -

IMO junk it and buy a different brand - I have seen and read your exact story atleast 25 times in the last few years .

If you dont believe,borrow a friends HU and swap it in,I bet you your system works fine

 

[tplaya07 10+ year member]

I had a similar problem with a Pioneer HU, which ended up being the RCA's grounding inside the unit. I was able to solder a short piece of wire from the negative (RCA outer shielding) to the case and fix the problem.

 

[NhustlaR 10+ year member]

before tearing your Hu apart, try a GLI?

 

[danz24 10+ year member]

ya i think it is witht the preouts because when i connect speakers to deck it works fine.

adn tplaya07, i dont fully understand you suggestoin..

and whats a GLI?

 

[bonesninja 5,000+ posts]

ground loop isolator

 

[tplaya07 10+ year member]

Firstly, if you have any kind of warranty, get the unit replaced. If not, you can open up the casing and put a multimeter on the outside casing of each of the female RCA inputs on the back of the HU, and put the other lead on either the HU casing or the ground prong on the inside of the HU. With your MM set to ohms or resistance, you should not get a reading of more than around ~.2-.3. Or even better, if your DMM has a diode tester, you should hear a beep when you touch the leads.

Here is a pic of what Im talking about, but you may have to open the case to do any further testing or to solder the wire if this is your problem.

http://img182.imageshack.us/my.php?image=dsc000034mi.jpg

I was having problems hosting the pic, so the link will have to do for now.

 

[johnecon2001 5,000+ posts]

before tearing your Hu apart, try a GLI?

Those things are useless. Banaids.

If you cut your arm off, would you put a Johnson & Johnson Kermit bandaid over it? No, you'd go to the hospital.