Strange power hiccup on m2-atx when turning my car off.

**Sonicxtacy02** · 05-27-2011, 08:12 AM

I recently changed my car PC installation over to another motherboard and as a result changed my power supply back to the m2-atx. Keeping all the components (Power, USB etc) the same i figured it'd be an easy deal. I am now having a problem that i really dont know where to begin troubleshooting. Basically the power to my car PC dips down to <9volts whenever i take my key out of the ignition. It only happens for a second before the multimeter jumps back up to 12v, but its long enough that the m2 cant compensate for the dip and keep my system alive. I can hear the processor fan speed slow for a second before it picks back up and the computer reboots.

The thing thats kinda baffling me is this really shouldn't be happening. Both of my batteries are less than a year old and the auxiliary battery powers nothing but the car PC and a single (but new) amplifier. I never run the system with the engine off and both batteries still test fine. So where should i start checking? Could a loose wire cause the problem? Again, i'm using all the same wiring, same battery isolator etc. What could cause a dip in detected voltage from a healthy battery?

**soundman98** · 05-27-2011, 04:32 PM

so if you turn the ignition off, but keep the key in, the power stays around 12v? but as soon as you pull the key out, it momentarily drops?

i wonder if it is a worn ignition assembly causing a brief short.

**Sonicxtacy02** · 05-28-2011, 06:35 PM

actually i was wrong.. i just did tests, the power dips when the ignition is turned off, regardless of the key still being in the cylinder.

**soundman98** · 05-28-2011, 11:33 PM

ok, does the power also dip when you turn the ignition on?(if something is shorted inside the ignition)

it really sounds like a car problem more-so then a pc issue...(maybe check your cars forum, or a local dealership?)

**Sonicxtacy02** · 05-29-2011, 07:40 AM

Yes, it also dips during crank. I figured it had to be something with the PC because i never had such problems with my prior motherboard and DSATX power supply