Commate P2BXA mobo lost 3.3v power

[Machy2k]

Does anyone know the commate P2BXA motherboard?
My board is still running stably, but i noticed that the cpu fan stopped running when the pc boots into windows..
when I checked it out I noticed that the board has no 3.3v power so I gather
the cmos switching is not working also the usb buss does not recognize devices.
I fixed the problem once by switching power supplies, but problem returned.
All caps seem ok on my inspection so I wondered if it could be any mosfets or voltage regulators or how to determine if it is definately capacitor related when all I have to test them with is a v-ohm meter.
Any help will be greatly appreciated
Thank you

[Topcat]

Welcome to the forums!

Have you checked the PSU's 3.3v rail? That would be my starting point. The fan headers run off a 12v rail, not 3.3. Also, check in the BIOS and disable power management. That will cause the fans to spin down when the load is light or temps are low. Disabling PM in the BIOS should force the fans to stay powered up all the time.

[Machy2k]

HI Topcat, Thanx for the reply about my Commate mobo.
Yes I actually have tried 4 power supplies.
When I changed the first one the problem disappeared for a while, 3 month's maybe.
I have a lot of old pc's so supplies are easy to come by, but I finally bought an Antec smartpower 350 because ther older supplies were soft..
the antec allowed my board's usb buss to recognize devices, also I believe I disabled the power management in the bios
and the other thing is I use a Soyo Techaid and I do not get the pci 1st led, nor the 3vsb led, and the 3.3v led is very dim .
so I can use the system by plugging the fans directly to the power supply, but if I use my 800mhz pIII chip and mx440 vid. card I lose usb device recognition, and that led me to youse guys

[Rainbow]

Re: Commate P2BXA mobo lost 3.3v power

I doubt that it would work without 3.3V. The chipset, DIMM and AGP slots are all powered by 3.3V on P2/P3 boards.