New project - fan and mame question

[bjhille]

I purchased an HP Pavilion p6570t a few years ago.  When I plug the unit in (with the power turned off, no OS running or booting) the PSU and CPU and case fans all come on at very high speeds.  They will stay this way unless you:
   * turn the computer on, hence booting into Windows 7 when then the fan speed kicks down
   * unplug the computer.
 
These are the only two situations where the computer fans will turn off.  While this behavior has been happening since I took it out of the box I know it isn't a dust problem.  I never called support because the computer was being left on all the time anyway, so I didn't care.  Now, I have purchased a new computer and was going to use this one in an arcade cabinet.  I want the computer to be able to be off without the fans running but remain plugged in.
 
I figured there was a BIOS update as mine says it's a "American Megatrends Inc 6.07, 5/19/2010".  I can't find an update on HP's site.  Any ideas?

Also, this is a i3 Dual with 12GB of RAM.  I don't think I should run the latest version of mame as I don't believe this will have the horse power to run it.  I was going to run Mala as my front-end, but am not sure which version of name I should start with.  What do you guys think?

Thanks.  Brian

 
Any thoughts as to how can I have the computer plugged in, but turned off and have the fans off?  It can't be heat because I can leave it this way for days in the cold basement and it will just keep running.

[dkersten]

My first thought would be that the power supply is bad.  If that isn't it, then the motherboard is bad.  Something is telling the 12v rails to turn on in the power supply all the time, regardless of whether the motherboard is powered up or not, and so all 12 volt items are running wide open.  Once the motherboard is powered on, it dials the RPMs on the fans down based on the temp of the sensors on the motherboard and the settings in the bios.  I have seen this a few times, and it is usually one or the other. 

An ATX power supply needs a signal from the motherboard to turn on, but the 12v rails in yours are powering up without that signal.  So to troubleshoot, I would open the case and unplug the main 24 pin harness from the motherboard but leave all other things plugged in.  Then plug the power supply in and see if the fans come on.  If they do, it is the power supply.  If they don't, it is more likely to be the motherboard that is signaling the power supply to come on but not actually turning itself on, and the motherboard is the likely culprit.

I would guess with about 95% certainty that your computer uses a standard ATX power supply, but there is a very small chance that they used something proprietary, usually when that happens it is a standard PSU with a few pins different on the motherboard connector.  You should be able to track this information down pretty easily though.

As for mame, I would think that a gen1 core i3 cpu would be more than sufficient to run any version of mame.  There might be a couple games that won't run well, but overall I wouldn't hesitate to run the latest version, I have run .153 and .154 on half the CPU of an i3 with no difficulties.

[Vigo]

If troubleshooting the mobo fails, you can just unplug the fans from the mobo completely, and wire them to an old 12v DC wall wart. When you have your computer on a smart strip to power your cab, the fans will be plugged into a slave outlet and they will shut off automatically when your computer is powered down.

While you are at it, I would personally go the extra step and buy a couple nice quieter fans to use that are a cut above the old HP fans. Maybe decase the motherboard and have a few larger fans mounted on the cabinet itself.