Question : Problem: PC will not power up.

I have a self-built PC using an ABIT-KN8 SLI mother board. The PC became intermittent as to whether it would start or not and now it doesn't start at all. I follwed some advice from previous posts and found two things for sure: 1) if i jumer the green wire on the 24 pin connector to ground (Power supply to mother board connector), the system starts fine. I checked the power on switch that runs from the front panel to the mother board and it tests OK. I get continuty when I press the button. Release the button and continuity goes away, as it should. Next, I tried shorting the two pins that that power on switch connects to, still no power up. But, like I said, shorting the Power On pin (pin 14, green) to ground powers up the PC.

My question is, rather than pull the mother board to try and find the problem (and maybe create more problems), is it safe to just short pin 14 (green power on wire) to ground at the connector and leave it like that? A better solution, I think, may be to tie the power on switch to the Power on wire (pin 14) and ground. I may loose the functionality to be able to shut down the PC using the switch, but this PC stays on 24-7 except for an occassional reboot. I'm looking for an easy way out.

What is your advice?

Answer : Problem: PC will not power up.

>is it safe to just short pin 14 (green power on wire) to ground at the connector and leave it like that?

No.

I've built over a dozen computers and servers, some in the $6-8,000 range.  Also did tear-downs and rebuilds of several dozen workstations and a half-dozen notebooks.

I've never had to short anything to make it work.  I've always followed the schematics from the motherboard + chassis + PSU suppliers.  If it's a tear-down, I always make my own sketches and/or take digital photos at each stage.

Jumpers are used for diagnostic purposes.  Wherever jumpers are required for assembly, you will find labeled/numbered posts and pre-fabricated jumper.

I don't know if any ON/OFF computers are made any more.  I haven't seen one in quite a few years...a Pentium processor with 96MB of RAM, IIRC.  All modern desktops, notebooks, servers, etc. come with a logic circuit.  Push the hardware button (which you've tested already for continuity) and it engages logic for power up, power down, sleep, hibernate, etc.

This is controlled by the BIOS and OS.  From your description, you may have messed up the settings in the BIOS, or left the switch in a confused state.

Try these:

1. pull the battery for the CMOS (BIOS settings).  Short the jumpers that will clear all BIOS settings.  See your motherboard schematic for the jumper numbers.  They will be in close proximity to the battery.
2. Reinstall battery.
3. Boot (POST) and enter BIOS setup.
4. choose default settings ("conservative" or "fail-safe").
5. see if desktop will power cycle reliably


--reset soft-switch--works on desktops and notebooks with "confused" power buttons
1. unplug mains (AC) from wall
2. remove batter power (if notebook)
3. push down power button for 10 seconds
4. release
5. plug in mains
6. attempt to power cycle
7. if power cycles OK, re-install battery