Whining/interference - probably related to power lead

[JorisS]

Hi all,

recently purchased a 'new' car, it had a JVC cd-player in it and old but functional amps for front and rear speakers (separate).

Problem is there was a whining noise coming through the speakers, which was most clearly heard with low volume. It reacted to motor RPM through increased whine pitch/frequency.

Seller told me it was similar for the original radio which was in - they bought the JVC to 'fix' it but kept the problem. I.e. it's not related to the actual stereo.

I just swapped it for our Pioneer unit, it doesn't whine but 'crackle' through mostly one of the rear speakers. But only when the ignition is on.

Thing is, the original owner of the car, who mounted the amps and all, somehow wired the radio so it can be turned ON without the car being on contact at all. In addition, when the car is started with the radio ON, the 'Check engine' light in the display remains lit (if one starts the car with radio OFF it doesn't).

So I'm guessing he picked a poor place to connect the stereo to a permanent 12V line, causing both the interference AND the warning light to show when starting the engine with radio on.

Any ideas how to easiest fix this? So when I turn on the radio with the car not having the keys in at all the sound is fine, as soon as I turn it to contact (without starting the engine) it starts to interfere.

Hope somebody knows //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[mile098 10+ year member]

first thing find where he took the permanent 12v..he probably didnt feel like leading the wires to the battery so took a shortcut like u said...and it could like be the load thru that single wire...and as far as the no ignition starting sequence is concerned thats easy, constant + with memory into the memory cord...not sure if u follow me, thats the way we call those cords here

 

[JorisS]

No I don't really follow //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I'll have a look at the wiring to see where the +12V is coming from.

As far as I'm aware there's 3 power related cables on my stereo:

Red, yellow and black. Black being ground. One being permanent +12V, the other one normally being coupled to ignition. I reckon both are permanent +12V now. Have to check the manual to see which one should and which one should not be...

 

[mile098 10+ year member]

the yelow one doesnt have to be coupled with the ignition...there should ne 2 yellow ones..i dont know it by heart ill take a look tmrw how i did mine

 

[JorisS]

Ok cheers. I don't have 2 yellow...