computer doesn't power up immediately, power down is fine

[GOD]Anck · 12-14-2009, 06:16 AM

For a few weeks now, my computer doesn't immediately start when I press the power button. Sometimes when I try 20 minutes later, it works, and sometimes it even powers up by itself 10-30 minutes after first pressing the button. I use the same button to power down at night, and that always works on the first press without fail so I suspect the actual switch is not broken. I haven't touched the bios or changed any components, it just started doing this for no apparent reason. What kind of failure could cause this behavior?

pixellany · 12-14-2009, 06:38 AM

When you press the power button, check to see if the drive is spinning. Also, what lights do you get?

Is this a laptop or dekstop? For a desktop, see if there are some lights on the back of the case (in the same area where all of the connectors are).

When you press the button to power down, do you get a menu with options? If not, then do not power-down that way---ie always use the software interface to power down.

[GOD]Anck · 12-14-2009, 06:49 AM

Neither the drives nor the fans spin, and I get no lights either. Until it magically decides to power up, that is. Then everything comes on as normal. It is a desktop, but headless. The power button generates a clean shutdown via ACPI, so that should be safe, but just in case, I did try shutting down from the command line (runs linux, cli only) for a few days. Symptoms didn't change.

pixellany · 12-14-2009, 07:17 AM

I would say it was the power button, but I don't know why shutdown would be normal. Regardless, I would open the case and bypass the switch to see what happens. You might have to also bypass the motherboard connections---ie make the correct contact closure directly to the power supply.

I think the power button activates a relay--either in the Power supply--or on the MB. The relay may be sticking.