Problem with 12v power

[cinOxen]

Hi,

I just got a Mach II GT and was able to set it up successfully for one bootup and ran it about a day. The second time I tried to boot it up the motherboard wouldn't power on at the proper time. In fact the motherboard won't power on at all when it is plugged into the Mach II's molex plug. Unplug it and it boots up fine. The motherboard power switch cables are connected properly. If I unplug the Mach II's molex the computer turns on at the appropriate time but then the mach II shuts down due to "no power" (or something like that). I took another power supply and found that it wouldn't even turn itself on if it was plugged into the mach II's molex plug. This is a power supply I use for testing parts and works fine - I plug it into the mach II and it won't power on.

Not sure what I'm doing wrong or if I'm doing anything wrong. It seems like there is a problem related to the molex plug/controller board (or simply user-error).

 

[K404]

Does the mach 2 take most of its power from the mains or the computers PSU? Its possible the PSu you`re running isnt strong enough to power the computer and the Machs board. Please can you post a full system spec for us?

Cheers,

Kenny

 

[cinOxen]

Hi,

Like I say I've tried a couple power supplies. The main one is a silverstone zeus 650w. The other was a 350w with nothing else attached, just the prommie.

The rest of the specs are toledo X2 (4400), Lanparty SLI-DR, XFX 7800, OCZ 2GB platinum, maxtor 36GB.

I don't think it is a problem with load. It worked the first time fine.

Tried this experiment again: Took a power supply and attached a fan to it and turned it on – the fan turns. Plug the molex from the prommie (unplugged from AC) into a molex from the PS – the PS turns off and fan turns off. Unplug the prommie, fan turns back on.

Just checked and the 12v of the molex has no resistance between the prommie’s case although I don’t see any nicks on the wire or anything to explain that.

 

[cinOxen]

The only thing I can think of that I did between the first success and now is plugging in the USB header, perhaps I shorted out the controller

 

[K404]

Sorry, i`m out of ideas... I`m not a Mach user

 

[cinOxen]

No worries. I removed the molex cable from the controller and tested the 12v pin directly off the controller. There is still a short between it and the case - it must be traveling through the ground wire. I think I have no choice but to replace the controller.

Has anyone heard of such a short before or heard of an improper USB connection damaging the controller?

 

[cinOxen]

Well started unplugging things from the controller and suddenly the problem became obvious. i choose a bad spot to route the wires from the rear-heating element - right under a motherboard mount.... problem solved.

I'm more happy than embarrassed