m1-atx: no hd power

**blasterguy128** · 03-06-2005, 03:05 AM

I finally got around to installing my carputer and now it looks like my m1-atx psu isn't working right.

I made all the connections and when I start the car, the motherboard powers up but the harddrive does not. I connected a regular atx psu and it worked fine. I looked at the m1 and everything looks fine (nothing melted,no burnt fuse, etc.). Then I tried different jumper settings and that did nothing.

I don't know what else to try, so if any of you have ideas, I would love to hear some. I am just about ready to break the m1 into little tiny pieces just for fun.

Also, I found this thread but I didn't find it very helpful because at the end neon_eddy says he fixed it by getting a new "power trench thingy", which I have no idea what he is talking about.

Thanks,

steve

**kyrenia** · 03-06-2005, 11:45 AM

try using a volt meter on the hard drive connector to measure the m1-atx output red = +5 , yellow = +12 black 0v. the voltge levels must be ok on the mother board connector for it to boot. might be a cable problem . try measuring the resistance between the hard drive wires and the motherboard wires . should be 0 ohms ( shorted)

**blasterguy128** · 03-06-2005, 05:06 PM

I bought a volt meter and tested everything. All my connections seem to be working perfectly. The +5 and +12 on the molex hd connector measured perfect. Then I tested the resistance and it was about 2 ohms, is this bad?

Also I didn't test 20-pin motherboard connection, should I?

I don't think it is a cable problem because the power output is fine, so the psu connections look good. I connected a regular atx psu and everything worked fine including the hd, so its not any cables for the comp.

I feel like I've tried everything, is there anything else I can try/test?

**rando** · 03-06-2005, 05:39 PM

What are the voltages on the 4pin molex when it's plugged into the hard disk (i.e. under load)?

**blasterguy128** · 03-06-2005, 05:50 PM

Originally Posted by rando

What are the voltages on the 4pin molex when it's plugged into the hard disk (i.e. under load)?

I'm sorry I'm pretty new to this. How do I check the voltage while it is connected. Should I cut the covering and check?

**rando** · 03-06-2005, 06:57 PM

you should be able to touch the pin contacts from the back side of the connector.

**blasterguy128** · 03-06-2005, 08:04 PM

Ok, I did what you said and tested the harddrive power while it was running. First I connected the meter and then I turned the comp on. So as soon as I booted the comp the meter went from 0v to 12v right away, and the same with the 5v.

Does the motherboard control how the hd is turned on or is it the psu?

This is very confusing because I figured if the hd has power then it should turn on.

**blasterguy128** · 03-06-2005, 08:47 PM

Alright, I just took some pics of my setup. Maybe if you see my connections it will help you see what I looking at. I tried getting some good pics of the m1-atx but with my setup it is kinda hard to see, mainly because the motherboard is on top of it.

http://geocities.com/carputerion/

**blasterguy128** · 03-06-2005, 09:54 PM

Oh and I forgot to mention that I am pretty sure I'm not overloading the psu because I have disconnected everything except for the mobo and the hd.

Epia V 1ghz mobo
3.5" 30gig hd

One thing I was thinking about was that I spliced into the remote turn on for my amp and ran an 18 guage wire from it, to the switched power on the m1. Could this be causing a problem?

Other than that I have just ran straight 10 guage wiring from the car battery to the m1-atx.

**drait** · 03-07-2005, 12:16 PM

When I first put together my CarPC it was doing the exact same thing as yours (no HD power). Turns out it was a bad IDE cable. Probably not an issue on yours though, since it works fine w/ a regular PSU.

Have you checked your car battery to make sure it's providing at least 12V? The M1 should still work up until it drops to 11V, but if it's close it might be wigging out. The smaller gauge ignition wire shouldn't affect it too much, since it doesn't draw its power from that line (or at least shouldn't).