Where do YOU ground your stuff?

[dfmorse]

Red Beard;

U may need to establish a + and negative bus distribution inside the cabin. That "screech" noise could be the DC-DC converter feed back into the audio system. By running a pair of wires direct from the battery, u may be able to eliminate said "screech".

DC-DC converters really put out some bad EFI/RFI noise.

What kind are u using? Brand? How is it wired? I think u mentioned using only a positive fused lead, which is why u should experiment with bringing the battery leads (both + &-) into cabin for distribution. Ferrite filters may be required.

Do u have a link to the DC-DC converter so that I can look up specs and wiring instructions?

I use the following arrangement:


Battery,Fuse, Winch Project : BussOverView

...

 

[Photoman]

Here is a picture from a 1997 that shows the ground point in relation to the e-brake etc.

Fwiw, here is another picture of a way that I was doing my ground circuits. This is from the engine bay but is representative. I run a number 8 wire around the cruiser and create ground points with these connectors. At each connector I also run a wire to the body to ground the connector. The number 8 wire originates at the negative of the battery that I am running the circuits off of. HTH.

Bill

 

[ArmyFJ]

Well this could help you out...Talks about ground loops. And interferences with multiple audio sources using multiple paths to ground.

Looking at this it would seem the closer you can get the grounding points for your Mac, Inverter, Head unit, Sub(if you have that) the better chance you will have of getting the ground to be the same true voltage.

Ground loop problems and how to get rid of them

Ground loop (electricity - Wikipedia, the free encyclopedia)

the wiki explanation is much easier to read.

Hope it helps.

 

[Red Beard]

Hey, Red Beard, sorry to hijack, but how do you have the Mac Mini wired into your truck? That sounds interesting. If you have a different thread or want to reply by PM, that's cool.

Thanks!

Check the ROTW in my sig, there's a section there.

I'm using a CarNetix P1900
CarNetix CNX-P1900

the PDF manual:
http://www.carnetix.com/installation/CNX-P1900InstallationManualV2_1.pdf


I've tried a 12 gauge line from the negative terminal to the P1900, but it didn't work as well as the ground I have now.

When I had a Ground Loop Isolator hooked up, I didn't get the screech, from what I can recall, but I had distorted sound quality at high volume on the head unit.

 

[ArmyFJ]

Have you tried to use one ground for all the audio devices and your inverter though?

 

[PHAEDRUS]

FWIW,
I ran a separate fuse block to the interior, mounted it next to the center console behind the e brake and then ran all my electronics in the truck from there. I used the first ground point that Bill (Photoman) posted underneath the center console and then grounded my stereo and cb and inverter from there. NO buzzing.

That said I would try the good body ground under the center console before I got any further with this.
Dave

 

[AppleTech]

What I did in my 4Runner was run a ground cable from the device to the seat bolt, or some other bolt that goes directly through the floor.

Then, I attached a wire from the outside part of that same bolt and wired to a hole in the frame I could put a bolt through. Before hooking up the ground bolt, I stripped the paint off the place where the bolt or nut would be touching the metal. hooked everything up, then simply painted over the bolt so there was no bare metal.

Worked great for my CB with ECU noise issues.

 

[ArmyFJ]

What I did in my 4Runner was run a ground cable from the device to the seat bolt, or some other bolt that goes directly through the floor.

Then, I attached a wire from the outside part of that same bolt and wired to a hole in the frame I could put a bolt through. Before hooking up the ground bolt, I stripped the paint off the place where the bolt or nut would be touching the metal. hooked everything up, then simply painted over the bolt so there was no bare metal.

Worked great for my CB with ECU noise issues.

Haha, the deception user name...I figured from your name you were going to have a very Mac specific solution.

Matthew

 

[Red Beard]

Thanks for the advice guys. Shoulda just came here in the first place. Anyway, I'm going to take care of this issue this weekend. Going to try to ground it underneath the center console. I'm also going to check the ground of my touch screen. The screech noise changes when I interact with the screen. So I'm going to ground everything at that point. If that doesn't work, I'm making my own damn ground.

I'll let you guys know how it all turns out. Thanks for all the input!

 

[AppleTech]

Haha, the deception user name...I figured from your name you were going to have a very Mac specific solution.

Matthew

Haha, usually I would offer a Mac-centric solution, but power is power! To prove that my handle is true, I will share some of my Mac specific knowlege below

Thanks for the advice guys. Shoulda just came here in the first place. Anyway, I'm going to take care of this issue this weekend. Going to try to ground it underneath the center console. I'm also going to check the ground of my touch screen. The screech noise changes when I interact with the screen. So I'm going to ground everything at that point. If that doesn't work, I'm making my own damn ground.

I'm interested to see pics of the progress on this... mounting, wiring, etc. I would like to do it once flash HDs come down in price... that way you won't have to worry about your HD dying in your Mac Mini as often (trust me, it will die quickly because it is bouncing around in your truck all the time). But they are cheap, so don't worry about it - should last at least a year if you take it easy over bumps.

If you have another Mac, I would recommend that you make sure you create a disk image of the final config of your Mac Mini once everything is up and running... this way, if you mess something up or the drive dies, you won't have to reconfigure everything, just copy the image to the new drive and replace... it will be like nothing happened. PM me if you want more info on how to do this.

I would also make sure you have some port extenders for the USB and FireWire ports (or have easy access to them). Being able to hook up a USB keyboard and mouse is necessary for many troubleshooting steps, and being able to hook up a firewire cable to re-image the computer without removing the whole setup is a huge bonus.

 

[Red Beard]

I'll let you know of the progress. I'm definitely looking into getting a fuse block somewhere in the cab for all this stuff, I definitely want another USB hub, a good one too so I can hook even more stuff.
Right now on one cheap in the cab hub I have a wireless keyboard and mouse, verizon modem, griffin powermate and an extra slot for guest USB devices. 1 is hardly enough for "extra". directly connected to the mini is the usb from the touchscreen and other stuff, filling all the slots.

I'll let you know how it all goes!

 

[ArmyFJ]

Haha, usually I would offer a Mac-centric solution, but power is power! To prove that my handle is true, I will share some of my Mac specific knowlege below

Never doubted it. Just not what I expected initially.

Matthew

 

[Red Beard]

Just an update. I have ALL my consoles torn apart, regrounded everything and I'm still having not that much better or worse sound quality.

The screech is definitely coming from the screen.. if I dissconnect the USB input cable, it goes away.
But there's some other hum now, not alternator whine either. I'm going to keep trying different things before I solve this.
I have to solve it soon, because snow is coming and I have to prepare.

I'm thinking:
ground the mac mini (send a cable from one of the metal ports and ground it, see what happens.)
Make sure everything is grounded to that new spot. ?even switches for the lights?
In some spots, the ground cable is switched up to 12ga wire because that's all I had at the time, maybe I should being it back to what is started at (like 16 ga or something)

 

[AppleTech]

Just an update. I have ALL my consoles torn apart, regrounded everything and I'm still having not that much better or worse sound quality.

The screech is definitely coming from the screen.. if I dissconnect the USB input cable, it goes away.
But there's some other hum now, not alternator whine either. I'm going to keep trying different things before I solve this.
I have to solve it soon, because snow is coming and I have to prepare.

I'm thinking:
ground the mac mini (send a cable from one of the metal ports and ground it, see what happens.)
Make sure everything is grounded to that new spot. ?even switches for the lights?
In some spots, the ground cable is switched up to 12ga wire because that's all I had at the time, maybe I should being it back to what is started at (like 16 ga or something)

From my experience, ground wires are usually a larger ga than others. Is the touchscreen powered on its own? If it is, I would run a dedicated ground for that to one side of the chassis (removing the paint and putting a bolt through a hole in the chasssis, then painting over that spot). This will ensure that the touchscreen noise is dissipated directly into the chassis, far away from other devices. Next in the troubleshooting process would be to ground the Mac Mini directly to the chassis as well (maybe even on the other side of the frame).

Just my .02

 

[Grolar]

Did anyone mention running a (-) wire through the firewall to the battery? Isn't that the cleanest ground you'll ever have?

 

[Red Beard]

From my experience, ground wires are usually a larger ga than others. Is the touchscreen powered on its own? If it is, I would run a dedicated ground for that to one side of the chassis (removing the paint and putting a bolt through a hole in the chasssis, then painting over that spot). This will ensure that the touchscreen noise is dissipated directly into the chassis, far away from other devices. Next in the troubleshooting process would be to ground the Mac Mini directly to the chassis as well (maybe even on the other side of the frame).

Just my .02

The Screen is powered by the Carnetix P1900, which also powers the computer..

The screen came with a cig adapter. I cut it, and stripped the wires. The shield, I grounded. The inside wire, I sent to the power.

Now, I have the computer hooked up through a totally redundant setup, but it doesn't get nearly the feedback as before:
I have a cheap inverter, its connected to the newly installed fusebox. I have the AC adapter plugged into that, later converting BACK to DC to go to Mac, and that's how the mac is powered, less feedback.
I don't want to keep that setup, but its good for now.

So, what I have found is that the computer, when hooked up the ideal way, is grounded well. I gotta figure out a way to ground the external psu better, I think.
And weird static comes over the speakers when I get to a certain dB level. When I amp up the audio, about 90% of the way, I just get static. Any idea what that's from?

A lot of questions, sorry. But there's just so much in my mind that doesn't make sense

 

[Red Beard]

Did anyone mention running a (-) wire through the firewall to the battery? Isn't that the cleanest ground you'll ever have?

Actually, doesn't work.. I sent a big gauge (yet long) to the neg terminal and it wasn't as good as the chassis one I have now.

 

[C6H12O6]

If you know you're not going to be using this inverter set-up for very long, I would recommend getting the inverter you will be using and troubleshooting all this with the correct, long-term set-up. Otherwise, you may just end up going through much of this again, or at the very least, for no reason now.

I personally think you are chasing your tail with the ground. If you have everything grounded well, and the chassis ground you are currently using is fine, your problems lie elsewhere. It sounds to me like you are dealing with maybe a couple different issues and not taking a very systematic approach to figuring it out. Changing multiple things at one time is going to continue to cause headaches.

I still think your problem is with signal interference. Have you checked all your connections? Unplugged them, then re-plugged them? Made sure none of the insulation got scraped off somewhere on the dash chassis? Made sure none of the signal wires are running parallel to a 12V source (yours or an existing one)? Ground everything to a good ground and start systematically looking elsewhere for problems.