Whining sound driving me nuts

**Snootch** · 05-24-2006, 11:59 AM

Originally Posted by Red GTi VR6

a seat bolt is generally NOT a good grounding point.

to make it a good grounding point you need to do a few things.

Clean off of the paint on the bolt it's self and on the surrounding surface. Usually the threads are covered in paint, which won't allow for a solid ground. Also, usually seat bolts have some gunk built up on them, either from spilled drinks, or from being put together at the factory with a thread lock or grease, or the like.

IF your seat bolt is clean of all of these things, THEN it can be a good groudning point. Else, I'd recomend drilling a new hole in the car, cleaning off paint, and using a fresh bolt.

Yes, I guess I should of emphasised the clean part.

I figured he'd be able to use it since it was being used already by the amp. It is a good ground point in the respect that it is welded directly to the main chassis of the car. It does need to be cleaned well. The best way to clean is using a wire brush, sandpaper, and a good solvent like Acetone for clean-up.

**Tibby93** · 05-24-2006, 12:01 PM

Originally Posted by Red GTi VR6

heh - yeup - you sure didn't read any of the posts...lol

HAHA After I posted that, I decided to read it for personal knowledge, and regretted posting my post LMAO

**RedGTiVR6** · 05-24-2006, 12:04 PM

**2k1Toaster** · 05-24-2006, 01:52 PM

Originally Posted by Tibby93

Im also curious to know why your car pc is also connected to the cigarette lighter. I know for a fact that the cigarette lighter isn't a good ground for audio because that ground travels quite a ways instead of going real short into the body... I learned that with my satellite radio, it was buzzing, then I grounded directly to the frame, and it stopped...

Thought of something else along those lines. If you are running the power off the cigarette lighter, then those cables are pretty small. I know that when I plugged all my crap into the lighter before the CarPC (laptop, dvd player, car charger, inverter for TV on long trips) the car would make a whine similar. It was the alternator saying "Unplug all that crap or I'll die!". And it did within a couple months.

So the question is, and I could be blind for not seeing this earlier, "Is the whine coming from all your speakers, or just a general whine noise throughout the cabin?"

Just a thought...

**tannie** · 05-24-2006, 10:10 PM

Thanks guys for all the replies, I will attempt each method and see if any works-ill be sure to get back to u guys to see who got it right

. Im sure the ground is good, I scraped it till i saw my reflection. As for running the ground for the carpc to the backseat, is it just to reduce distance or just so that all grounds are in one location? Because the distance wouldn't be reduced by much.

I cut the harness to the Cig lighter's 12v and am using that as an IGN for the pc.

What I dont understand is that my amp is currently turned off..... It's not receiving any power so there should be no ground loop in relation to the amp.
I will attempt to reground the HU to the battery first to eliminate any chances of a ground loop between the Carpc and the HU, but the amp shouldn't be related-or should it?
Would the length of the ground create enough resistance to cause a differential between the grounds?

As for the whining sound, I'm unsure if its coming from the cabin or speakers, It seems as if it is coming from all of the speakers.

**tannie** · 05-24-2006, 10:12 PM

Originally Posted by 2k1Toaster

Thought of something else along those lines. If you are running the power off the cigarette lighter, then those cables are pretty small. I know that when I plugged all my crap into the lighter before the CarPC (laptop, dvd player, car charger, inverter for TV on long trips) the car would make a whine similar. It was the alternator saying "Unplug all that crap or I'll die!". And it did within a couple months.

So the question is, and I could be blind for not seeing this earlier, "Is the whine coming from all your speakers, or just a general whine noise throughout the cabin?"

Just a thought...

After Reading this, I'm a bit concerned, what other ign/acc sources should I use?

**cabj21** · 05-27-2006, 02:29 PM

please help

i just got a Compaq evo d510 e-pc it has a bit of engine whine and a a bit of homing noise . So I tried to ground my pc to my car but as soon as I do that the engine whine gets louder and the homing noise gets faded. I grounded on a bolt that was touching bare metal. What am I doing wrong? Please advise

**Gortok** · 05-27-2006, 04:10 PM

Start a new thread...don't hijack this one...

**2k1Toaster** · 05-27-2006, 04:42 PM

Originally Posted by tannie

After Reading this, I'm a bit concerned, what other ign/acc sources should I use?

Usually under the steering wheel there is a 12v constant, and then a switched from your key. I would either just use that, or run a relay with that.

But the thing is you are only using that as the "when to power on signal", not as the actual power line. I thought you were. The ign/acc isw to tell the PSU (like an M2 for instance) when the car is on to start the computer. It really draws next to no power.

**tannie** · 05-28-2006, 01:43 PM

I regrounded just about every component to the same location but no luck, my only solution left is to change the grounding location. The whine did die down a bit, but its still pretty bad, any other suggestions? I guess I'll have to get an isolator.... Damn I was hoping it wouldnt come down to this. Thanks guys for the help, heres a new diagram of everything.

2k1, thanks for clearing things up.

Whats crazy is that I get a faint whine from the alternator when I have just my head unit on..... And it gets worse with the AC on-however, if only the ac is on theres no whine. I thought I had narrowed down my problem to just my carpc but I guess its a combination of everything.