Hard drive not detected on boot when in my car-works in my house

**Boxxman** · 04-27-2006, 11:11 AM

I did some searching on my probably and haven't found anyone who's had this issue.

I built my CarPC in my house, so I had my M2-ATX connected to a mini-ATX PSU. Everything worked fine, and I have successfully installed WinXp, all my software and CarPC frontends.

The problem is when I move my CarPC to my car. It boots as it should when I turn the ignition on, but on the POST it does not detect my 2.5" HD. Basically I get the SYSTEM DISK FAILURE message.

I have my carPC connected as follows:

12V HOT to the battery, GND to the body, 12V switched to my ignition and thats it. I dont have the amp turn on in use b/c its only putting out 3.6V so I connected my cars amp turn on to the switched 12V line from my ignition.

Other stats:
M10000 mobo
1 gig RAM
DVD+-R drive

USB devices:

Bluetooth, Wifi, USB HUB-(GPS, extra USB port, touchscreen, griffin volume control)

Any ideas why this only happens in my car?

**TruckinMP3** · 04-27-2006, 11:29 AM

I would suspect power is the issue.

My guess is not enough juice to spin the drive... this means the PC does not see the boot volume.

If the DC-DC PS works in the house but not in the car, the car electrical system is suspect.

Consider getting your charging system checked by a parts store (generally free).

They have a little handheld tool that measures info in the battery, alternator, and voltage regulator.

**Zebelkhan** · 04-27-2006, 11:41 AM

According to M2-ATX specs, the 5v output is 8 amps, or 40 watts.

http://resources.mini-box.com/online/M2-ATX/specs.pdf

From what I see, just about everything on your PC is using 5v, with total perhaps near or over 40 watts. So it looks like not enough power is the problem,

**FredTT** · 04-27-2006, 12:10 PM

You may not be getting enough power to the system from the car itself. Check the current coming back from the battery.

~Fred

**TruckinMP3** · 04-27-2006, 12:14 PM

Originally Posted by FredTT

You may not be getting enough power to the system from the car itself. Check the current coming back from the battery.

~Fred

See post # 2.....

**FredTT** · 04-27-2006, 12:20 PM

Originally Posted by TruckinMP3

See post # 2.....

I was agreeing with you. Now its 2vs1 (post #3)

~Fred

**TruckinMP3** · 04-27-2006, 01:49 PM

Originally Posted by FredTT

I was agreeing with you. Now its 2vs1 (post #3)

~Fred

Whatever, it could easily be both. The limit on the 5 volt rail could be less tolerant in a brown power condition from the car.

The PS should not be maxed or near max on any rail. It leads to problems like this.

**Boxxman** · 04-28-2006, 12:17 AM

I appreciate both suggestions. The reason I am going to lean towards the car issue (getting it tested) is that although I have all those items on the 5v rail, even when I unplug all USB devices, leaving only the computer with 1 HD and DVD drive, it still does the same thing.

I did measure that I am getting 12 V in from my car, so I guess it could be a current issue.

I'll find out soon.

**2k1Toaster** · 04-28-2006, 12:38 AM

Does the drive even attempt to spin up? I had a similar problem, but my 12v pin was loose on the molex connector!

**Boxxman** · 04-28-2006, 12:50 AM

Well my case cover is on so I can't hear it, but this is what is happening. Hook it up to my PSU in my house, computer powers on and HD detected. move it to my car and the pc powers on, but does not detect the HD, so I get no where. I can move it back and forth and its the same result.

I am curious if your computer even booted if you had a 12V connector loose. I know the connecters inside my case are fine b/c they work in my apartment.