Mobo starts in Stand-by? Why?

**Davefocus** · 03-16-2006, 06:13 PM

I'm using an old Amptron BKMVP4 mobo. I recently reset the CMOS and the PC starts in stand-by every time when using the dc power supply unit (CarNetix P1280)

. The PC works fine when using the ac power supply unit

. It is obviously unable to undertake PoST aswell.

1) What are the possible reasons for the PC starting in stand-by?
2) Are they any standard bios setting that may be responsible?
3) Any suggested solutions?

I intend to purchase a new mobo in a couple of months

but would really like to use the current one for the time being.

You're comments will be really appreciated.

Cheers,
Dave

**MatrixPC** · 03-17-2006, 09:56 AM

Did you take a look in Window's power option?
Take a look at power button behavior in windows. It could be set to "Stand-by" instead of Shutdown or Hibernate.

**Davefocus** · 03-17-2006, 10:03 AM

The power option is to shutdown when button pressed. The PC works fine when plugged in to the ac atx psu. The pc will only start in the standby state, even from first switch on.
Not sure if the 5vsb may be responsable?
Cheers,
Dave

**Davefocus** · 03-18-2006, 02:56 AM

Here we go, problem from the top. A customised cable was required to power mobo from CarNetix P1280. I had similar problem initially but seem to be resolved. Car PC has been running fine for 8 months, then I made the mistake of trying a mod that involved resetting the CMOS. The problem has reappear every switch on. Below is some details of customisation.

CarNetix P1280 customisation

The Patriot book size iCue BKMVP4 motherboard ac power supply is rated at 100 watts output. The CarNetix P1280 will provide 80 watts to supply the power requirements of the motherboard, floppy drive, CD ROM drive and hard drive.

The CarNetix P1280 output pin connections are:

Pin Wire colour Function

1 White 5 volts dc
2 Black ACPI return
3 Green ACPI power on
4 Red 12 volt dc
5 Black Ground
6 Blue DYLON

The MVP4 motherboard power connector pin connections are:

Pin Wire colour Function

1 Purple 5 volts dc
2 Black Ground
3 Black Ground
4 Green PS on
5 Yellow 12 volt dc
6 Yellow 12 volt dc

The Patriot book size iCue PC front panel header pin connection to utilise ACPI (only pins 1 and 2 required).

Pin Function
1 Ground (ACPI return)
2 Power supply (ACPI on)
3 Ground
4 Reset
5 Ground
6 Power LED
7 HDD LED +
8 HDD LED –
9 Suspend LED –
10 Suspend LED +

A modified power cable is to be manufactured provide the motherboard power supplies and utilise the ACPI (advanced configuration and power interface) function, thus negating manual power switch operation to start up the Car PC. The Car PC is to be located in the boot of the car. The following wiring diagram identifies the modified cables wiring.

http://homepage.ntlworld.com/david.h...1280cable.html

Should PS_ON still be used? Can you see anything wrong? Can you think of any other reasons?

Cheers,
Dave