M2-ATX isnt powering on in -20C

**nobb** · 01-20-2008, 01:53 PM

I thought this power supply was supposed to be good down to -40C operating. It was -20C this morning. When I start the car, the +12 volt line briefly powers on, then suddenly powers off. My Epia m10000 doesnt even get a chance to POST because the power is cut. Through my "valet switch," I cut +12v to the ignition wire going into the M2-ATX, then reapply the +12v. I do this 5 times (each time the M2-ATX behaves the same way as before) before the M2-ATX powers on like normal, my board POSTs and then everything works just fine.

Anyone have any ideas? What is going on and how can I fix it?

**jontz** · 01-20-2008, 06:28 PM

Something on your power supply doesn't like the cold (wow...that was obvious

)

It could be any number of things, including a bad capacitor on your power supply, bad transistor, loose wiring...

Sorry I can't be specific, but it is kind of hard to tell you for sure what is going on. Hopefully someone else here has a better answer for you...

**nobb** · 01-21-2008, 09:33 PM

Hmm, after some reading it appears that the M2-ATX has alot of unfixed timing issues (probably magnified at low temperatures):

http://www.mp3car.com/vbulletin/powe...tx-jetway.html
http://www.mp3car.com/vbulletin/powe...ng-mobo-2.html
http://www.mp3car.com/vbulletin/gene...-mornings.html

I guess I will try putting a switch to manually short the motherboard's on/off pins and see how that goes. But the temperature has gotten warmer, so I might not have a chance to do more testing any time soon. Anyone with a M2-ATX + M10000 care to share their experiences with this combination in the cold weather?

I contacted Chris at Mobile Computing Solutions (the guy I bought it from) to see if he had any ideas on this issue. Although I havent gotten a solution to the problem yet, he was very willing to help. Answered all my emails extremely quickly, even on a weekend. Seems to stand by his products 100%. Highly recommended, thanks Chris.

**Charly** · 01-21-2008, 10:43 PM

Also don't forget that car batterries put out less power when its cold

**nobb** · 01-21-2008, 10:49 PM

Nope, this was when the engine was running. I'm pretty sure it's the M2-ATX and its timing issues because my problem seem to match very close to those mentioned in the links to the threads I posted above. Some people suggest programming the PIC, or replacing some resistors/capacitors. But there doesn't really seem to be a definitive answer.

**nobb** · 01-22-2008, 01:05 PM

I just emailed Andrei of mini-box (the designer of the M2-ATX, I think). His reply was that it was probably my motherboard or ram which is getting fussy. But I powered the entire setup just fine in -20C with a standard ATX power supply, so I am really suspecting that I am having timing issues. These issues were supposed to be fixed in the newer versions of the M2-ATX, but I still keep reading posts of other people having these issues too. I have also read some posts by other users that also say they are having issues with the M2-ATX in the cold. Kind of dissapointed that the M2-ATX is advertised to work down to -40C, but does not even function properly in -20C for me.

In addition to the capacitor problems which are causing these issues, the user xtremak says that the PIC code on the M2-ATX causes (in some cases) the on pulse getting sent before the motherboard is fully powered:
http://www.mp3car.com/vbulletin/powe...hing-mobo.html

So other than shorting the on/off pins manually, replacing the capacitor, or reprogramming the PIC, I have no other idea what I can do.

EDIT: NVM I think I found a temporary band aid to the problem. Went into the BIOS and turned on the option to turn on after power loss. Booted up in -30C just fine.