M3 ATX plus MX motherboard = power issue

**koll48** · 02-13-2008, 02:33 AM

Please Help

I completed the wiring and installation of my first (newbie to carputers) Car pc however when I start my car (straight to start no waiting on the "ac on" option) The PC doesn't seem to be receiving power.

By receiving power i mean sufficient power I observed that my amp and USB devices such as my GPS receiver is powered on ( there is a red light on the receiver that lets me know) but my Hard drive, CPU fan, and VGA output are not being powered.

possible problems that I can think of are: my connection to the from to the battery from the PC, i twisted the wires and used electrical tape (battery power wire ~ + electrical tape + M3-ATX power cord). i also did the same thing for the ground cable.

Please help

Specs:
Foxconn 661MXPlus (micro ATX)..searched for power specs but no luck
Celeron 2.7GHz
M3-ATX
Lilliput 629GL
1200 watt amp
Honda Prelude

**Arrow** · 02-13-2008, 03:01 AM

Use a volt meter and test connect it between where the 12V and GND wires are connected to the board. You should see ~12V. If not, you have a wiring problem.

**DarquePervert** · 02-13-2008, 11:51 AM

I'm thinking that your hardware draws more power than the M3 can provide, namely on the 12v rail.
The 5v USB devices are powering on, so you know that you're getting adequate 5v power. That leaves 12v, since 3.3v is only used for PCI bus.

That CPU isn't the most power-hungry in the world. it's pretty middle-of-the-road as far as power draw.
However, the actual power output specs of the M3ATX aren't published, so it's impossible to know the actual output on each of the rails.
Blame this on mini-box.com.

**koll48** · 02-13-2008, 06:27 PM

I checked the voltage across the M3 at ground and power in and it is getting adequate power 12.302v when engine off and 14.63v when engine is on. I think it is the M3 ATX its not putting out enough juice.

**koll48** · 02-13-2008, 06:30 PM

Are there any other options for me without having to purchase a whole new power option?

!Idea!
Is there a way I can dedicate my P2 (4 pin second power ) to the battery and then connect the 20pin (M3-ATX ) source?

**Woofnstuff** · 02-13-2008, 07:57 PM

yes..., i saw a diagram somewhere for it here (i think).. but sorry i cant remember where

**koll48** · 02-14-2008, 01:10 AM

Ok i got the cpu fan on and running I believe i can hear the hard drive turn on but i am still not getting an image and the lights on my wifi card are not on as well I am currious what would happen if i where to do the following:

**Nepharius** · 02-14-2008, 11:10 PM

I'm going to go ahead and say nothing. You realise that all the 12V still has to come out of the power supply, it doesn't matter which wire you tap into they all come off the same rail. Conceivably you could tap into 12V from the car... but thats a recipe for disaster.

Are you using a laptop harddrive? That is a possible option for lowering the power required. Also unplug everything else critical to make sure you havn't just fried your motherboard.

For example unplug hdd and all other powered things but leave in the ram and CPU and see if it boots up (yes it wont go into windows but it will show some stuff on the screen)

Good luck

**diosagain** · 02-15-2008, 10:46 PM

I have a m2-atx that I will sell to you if you want. I have two and they both work perfectly. I will take the loss and give it to you for 50 bucks if you will pay shipping. I bought another when when I thought my first one was broken but it wound up being just fine.