Problems! - with car computer - help please

**BigGuns** · 04-11-2004, 02:16 PM

I recently got my car computer installed, but ever since then i've been having problem after problem, and i would really like some help.

Problem one beening a lack of voltage to the pc - humming sounds coming from setup?! should i worry?

Problem two: Noise! the sound of the pc is connected to the stock headunit of the car via a fm modulator.
I cant remember off the top of my head if there is noise when using an mp3 or not, but i'll have to test it again.
The noise sounds like its isnt quite tuned in right, but i've tried other freq' around the one stated, but no luck - i may try a completely new freq' range.
Im using unshielded RCA, which is next to a mains power cable, USB cable and VGA cable (this was installed a professionals - although im expressing worry to them about this).

Problem three: This is has only happened in the last few days, but the alternator seems to be producting a whine, the more i rev the engine the louder it seems to get? This only happens when the pc is powered on - but i believe this due to the lack of voltage being producted by the invertor, therefore making the alternator work harder, by producing more current?

Problem Four: Lilliput screen, dims way too much, when ever i switch and incidator on the screen dims when they come on. But even when they arent being used, it still happens but not as much.

Some other information which maybe useful:

PC : Shuttle pc - xp2000, 80gb hdd 7200rpm, dvd player, SN41G2 model
Car: 2004 model honda civic sport 1.6 vtec engine.
Screen wired to a 5 amp fuse ----
Invertor (pc power) 30amp fuse ---- wired to accessory line of the car (makes no difference if wired to the battery)
when nothing is plugged to the invertor output is about 165v - input 14.5v

Thank you for your time

**azcowboy** · 04-11-2004, 02:34 PM

For problem #1. Did you try the things that people suggested to you in the other post. Just a question since you didn't mention what you have done to fix the problem

2) I see two problems here.
A) The sound quality with an FM transmitter will never be as good as
when you are hooking it to your stereo or amplifier with RCA
cables. Its just the nature of FM Transmitters.
B) Not only are you using unshielded RCA cables but you are using them
next to power lines in which case they will definatly pick up noise
Other than replacing the cables with shielded ones I don't know if
you can fix that.

3) May be related to problem 1. But I don't know. Try fixing problem 1 and
see if that helps

4) I have seen alot of comments that the lilliput screens are just plain low
quality. So you may not be able to do anything about that

**mpattonm** · 04-11-2004, 02:42 PM

What is your head unit?

**BigGuns** · 04-11-2004, 03:17 PM

azcowboy - Yes i have tried the things people have said, but they have been of good

---- I really think it is the voltage causing the problem - since the pc needs 240v to run on but only 165v is being produced.

The headunit is a standard stock unit - i've search the internet day and night, looking for the aux cables so i can took up RCA to it, but with no luck. It can hold a cd player, i know that for sure.

**azcowboy** · 04-11-2004, 03:25 PM

Originally Posted by BigGuns

azcowboy - Yes i have tried the things people have said, but they have been of good

---- I really think it is the voltage causing the problem - since the pc needs 240v to run on but only 165v is being produced.

The headunit is a standard stock unit - i've search the internet day and night, looking for the aux cables so i can took up RCA to it, but with no luck. It can hold a cd player, i know that for sure.

If its supposed to be putting out 240V and its only putting out 165V then I would say there is something wrong with the inverter and you should try replacing it.

**jusatry** · 04-11-2004, 03:28 PM

go somehwere that sells a more powerful inverter and try it out. If it works, return it and try to find it on Ebay or something. There is a chance that since the inverter you bought is a POS, it is way overrated etc. Just a thought...

**BigGuns** · 04-11-2004, 03:32 PM

Me and my friend bought the same invertor, both output the same amount - so i guess it is overrated - but they cant do that can they? the ebay link is on here : humming sounds coming from setup?! should i worry?

By any chance does anyone live in the brighton/hove area who has an invertor i could try out?

**falconey** · 04-13-2004, 12:09 PM

Voltage is not a reason for altenator whine. Altenator whine is usually caused by poor grounds as well as running rca's and power wires alongside each other. You will never be able to correctly diagnose you're problems until you install things properly. I know the hype is all about shielded cables, but I've never used them and never have problems with alty whine. They help, but aren't a must. First you need to run the power and rca cables away from each other. It's best to do them on sererate sides of the car. After that check all you're grounds. The fm modualter should not be grounded near the head unit ground. This is a sure way to cause alty whine. Give it at least an inch or two away from the head unit ground. Modulaters not installed properly will easily produce noise and grounding is a major part of that install. You may even need to just start with the fm modulater and then work you're way to the rca's. Is you're inverter hardwired. If not you want to do that too; if you need help just let me know and I'll tell you how. Don't use a cig lighter connection unless you want alty whine. If all that fails ground the case of the computer to the chasis of the car. If that doesn't work then your head unit just doesn't have the capability to filter out the noise and neither does you're inverter. I bought one from walmart and even they're cheap azz inverters say they have noise filtering technology so your's may as well or it may not. Either way you shouldn't even have to get to that point if you do all of the above.

**falconey** · 04-13-2004, 12:18 PM

Man I just read you're other post. Good grief these guys were pro's? They actually ran power wires and rca's toghether? They should give your money back. Seriously I'd take it back to them and tell them how YOU want it installed. My advice is anytime you go to get something installed by 'pros' is to tell them how you want it installed and not to let them use their own discretion. They ran those wires like that to save time so basically by doing that they were saying screw you customer. They have to know that's not the proper way to do it. I do think that humming you were getting was because the psu wasn't getting enough power, but personally I would have them change the wiring there too. You should have that inverter running from the battery not the fuse box. Anyways if you have more questions post up or pm me.

**BigGuns** · 04-13-2004, 01:52 PM

hiya, i got some great news

I took to back to them, and they ran nice 4 guage power cable from the battery to the boot, made a local ground for everything at the back, put on a spilt-charge-relay, and add noises filters to the setup. I did have to pay for the relay and the noise filter, but sofar from what i've tested its working great, other than the humming from invertor (which is much less now).

I'll do some detailed testing tomorrow, as i dont have time today, and let you know how it goes.