Rail voltages before starting pc
I'm having trouble starting my boat pc. I typically have to remove the bios jumper and replace the cmos battery to get it to start, after it has been sitting there a while without power. Normally, the pc will power up, with fans, but not post.
Now, I'm not even getting to the power idle up phase. I'm getting the intermittent "on" signal (short) to the motherboard, but it is not powering up.
I checked the rail voltages and the only one I see is 5V (No 12V or 3.3V). Also, the 4-pin to the motherboard does not have voltage.
MY QUESTION IS:
Should all the rail voltages be on after the 12V is connected or does the motherboard send a signal back to the m2-atx to enable the 12V and 3.3V? The +, -, and ignition voltages are all correct. Just trying to see if the motherboard is the problem or if it isn't starting because only the 5V is being supplied.