M2 will not power on

**romycha1** · 04-29-2012, 06:45 PM

Read through a bunch of threads but didn't really find much on startup issues, just shutdown...

So I recently bought a pre-built PC from mo-co-so that has an M2-ATX already wired in.

On the bench I had no issues whatsoever with power on or off. Yesterday I finally had some time to install the PC and everything was working fine... The PC would startup fine with no issues what's so ever. This morning I start my car, and the PC will not power on.
At the moment, I do not have my amps remote-on wired to the M2... so I am hearing some thumping when I'm assuming the PC is trying to power up but failing.
But I did wire the constant 12V of the PC to a valet switch.

So if I flip the switch to OFF, then back ON, and the PC will finally turn on. But it turns off as if there was a hard shutdown, i.e. asking if I want to start in Safe Mode... etc...

Is it possible that I may have a bad PSU?

**SNOtwistR** · 04-29-2012, 06:51 PM

It sounds like its starving for power, if that makes sense. What size wire is feeding the power supply? SNO

**romycha1** · 04-29-2012, 07:54 PM

12AWG.

I've read that people have used 8AWG, but the mo-co-so instructions said to use 12 or 14AWG.

What's odd, is that it started up numerous times for a whole night with no issues... then all of a sudden it doesn't unless I toggle my valet switch.

**romycha1** · 05-01-2012, 12:38 AM

Odd... all day today, the PC has been starting normally.

Although, I did find that after 2 hours of the car being off, it did not shutdown. Maybe 4-5 hours after I had last turned it on, it had resumed rather than booting up from being shutdown all the way....
I checked the jumper before it was ever installed, and it's at the position where it sleeps for 2 hours, then shuts down....

Anyone have any ideas what's going on?

**mayhembdm666** · 05-01-2012, 01:45 AM

I would think again here, grounding issue... And that may explain the valet switch

**romycha1** · 05-01-2012, 01:57 AM

Interesting...

Would you be able to explain why you think it's the ground? I don't doubt you... I'm just failing to see what the relation is.
But I did ground the the PC to the metal frame (read: bare metal, no paint) behind the dash, and if it's worth anything, I did check continuity between that frame and the negative terminal on my battery and it was good.

**mayhembdm666** · 05-01-2012, 03:05 AM

In previous experience and testing stages we have come across some some of what you described above.

The thumping sound we had at one stage because the ground was not strong enough to handle the load from the PSU, So it would power up and then fail under load / current draw.
Once it was off/resetting it would power back up again and cause itself to fail. Also have experienced this with adding a amp to a existing connection and that not having enough pull to power the amp.

As for the valet switch, could this some how be completing the circuit with a secondary line when been held/toggled on?
If the power up of the PSU is higher then operation, it could need that little extra just to get past the power up.

Added to the random working/not working can be something as simple as vibration for a contact point/connection

-- Its just a thought, but does sound similar to what we experienced with testing/expansion
--- Possibly release some load from the PSU -> Remove PC Attached Devices -> Or bad seating of component

On your bench test, was was the PSU being used? if the same one, what were the connections from the PSU terminals

**mrbean_phillip** · 05-01-2012, 04:45 AM

I think you have a crappy motherboard with BIOS-issues.

**romycha1** · 05-01-2012, 11:01 AM

Makes some sense, but like I said, I grounded it straight to the battery and had the same issue. I may permanently ground it to the battery to see if it continues.

I don't really have any other devices attached to the PC.. 2 USB extensions, the monitor, and a wifi antenna.
And yes, same PSU I used when testing. I connected the PSU directly to my digital power supply, no switches.