Another "PC Won't Power Up" thread

[Stickboy]

Sorry to post another "PC Won't Power Up" sob story. I read the boards for about an hour, but couldn't find an thread that was close enough to my problem:

My PC won't power up. (It's a 5 year old Quantex P2-400 /64 MB Ram, 11 GB HD, 32xCD and 1 Floppy) It has an 230W ATX power supply.

Usually, I leave the machine "on" all the time. I came home one day, and the machine was off (Troubleshooting step #1: Ask wife if she turned the thing off...she said "no." ) When I tried to turn it on...nothing...no fan, no lights, nothing.

If I completely unplug the machine, and then plug it in again, I get the ever-so-subtle dimming of the house lights for a half second, and occasionally see a spark in the outlet. Now, when I press the power switch, the power LED comes on for about a second, it sounds like the fan comes on, but then, nothing. Subsequent cycling of the power switch yields nothing...stone cold dead (not even the 1 second of the power LED).

I tried different outlets in the house (direct off the wall and through power strips) I tried a new power cable. I verified the voltage switch was at 115V.

I opened up the machine, and found no circut breaker or switch on the power supply (none on the outside, either). I reseated all power connections to the motherboard and all the drives. Still, no luck.

I bought a new, 300W power supply, replaced it, and had the same problem (the LED coming on for a second or so if "freshly" plugged in, but then...dead.)

Now, I began searching the SysOpt board for help. Based on some threads suggestions, I put the *old* PS back in, and short circuited the green and black wires. The fan came *on*, which tells me that the PS is indeed, okay. I plugged the PS back into the motherboard, and then tried plugging the PS into 1 drive at a time, and still, no joy.

I re-seated the power switch leads into the motherboard, plugged the PS into the motherboard and all the drives, still nothing. Then I disconnected the power switch from the motherboard and tried to short the two pins with a paper clip (the same paper clip I used to short the PS, earlier). Still nothing.

Finally, I kind of looked around and it doesn't seem like the motherboard is grounding against the case...I don't think this would be the problem anyway, since the machine was fine one day, and dead the next...there was no "trauma" to the PC or anything that could have knocked anything off-kilter.

So, what can I try next? somebody had a similar problem and a recommendation was:

"I've gone through this before. The problem was for some reason corrected by resettng the CMOS."

I have no idea what this means.

Anyway, there's where I stand. I'd greatly appreciate any help in trying to fix this, or a recommendation of what kind of new PC to start shopping for

Thanks,
-Stickboy

[rrockingb]

Hi stickboy

from your post it really sound like you have a short because of spark at outlet.

First thing I would do is disconnect everything hardrive,cd rom,floppy and any printer or anything else you have connected to computer, this includes power cord.

Next remove memory and video card then reseat them back in, remove battery from motherboard carefully it just slide out to the side DO NOT PRY UP you can break holder. Its about the size of a quarter leave out for about 5 mins this should clear your cmos, look in your manual for a jumper also that will clear it. Then reinstall battery, plug power cord in and see if comp will post.

If it does shut down computer and plug back in one item at a time restart and see if it post if so continue same procedure until you locate item that has shorted out.

If comp does not post first time try another memory stick if you have one, then try same with viedo card. Or if you have another comp you can check this parts out on to see if they work, If they do then since you tried a new power supply it most likely motherboard as I have never know a cpu to cause spark at outlet.

You could remove board from comp as last resort just to make sure it is not shorting out, and try to see if it will post then.

Post back your results and we can go from there.
Good luck

reny

[nemesys777]

I had a similar problem. My problem was caused by a bad RAM chip. (they can go bad)...Remove the memory altogether and turn it on then..(it should at least power up and beep several times if this is the case)
Now for CMOS:
I have seen computers not power up because of a bad CMOS setting(like overclocking..etc.)
There are two ways to short the CMOS on the motherboard. The first way is to check through your mother board manuals and see if there is a way to remove a jumper from the motherboard (this works for my computer) Otherwise you can remove the motherboard battery and short it out (paperclip between two contacts while plugged in)
Also a bad perhiphreal might cause this..just try one at a time removing and checking.
I know you said you tried different outlets but it sounds peculiar that your lights in your house would dim because you plug your computer in..(the spark too!) A computer should in no way cause that to happen..not enough amperage use...Maybe not the cause of your computer failure..but definately something to look into. Good luck man..lemme know what happens.

[EasyFast]

I had the same problem as you and tried the same things as you, except I didn't buy a new powersupply, but I was about to.

Despite my checking every connection, and it kind of stumped me how it happened, but here is what happened;

Simple, the power plug of the CPU fan is plugged into my motherboard. My CPU fan power plug mysteriously became unplugged fromt the mother board. As a safety feature, the mother board will not allow your system to POWER-ON unless the CPU fan is working upon boot. This is done in the bios, so there is only a moment of power before it shuts everything off.

Make sure this is plugged in. Some mother boards don't have this feature, but some do.

I am glad mine did, or my CPU would have gone up in smoke!

[Stickboy]

Hi Team-

Well, the troubleshooting continues with no avail. Since we last talked, I've done the following:

Replaced the motherboard battery (actually, that was the *first* thing I did, but I forgot to mention it)

I reseated the CPU fan connector

I unplugged *everything*...RAM, Video Card, all PCI cards, drives, etc...so that the only thing connected was the Power Supply to the motherboard.

All my efforts have been to no avail, I get the same results (although in my observations, I have noticed the following):
If the machine is "freshly" plugged in, when I press the power button, the CPU fan begins to spool up (and the power LED comes on). About a second later, everything dies. After that, successive attempts to push the power switch do nothing...absolutely dead.

If I completely unplug the machine (unplug at the wall end and the PC end), then re-plug it in again, I get the same "1 second of life." on the 1st attempt to power up.

Any more suggestions?!

Frustrated,
-Stickboy

[rrockingb]

Stickboy

Have you or can you try different ram, video card and cpu?
If you have and you are still getting this result then it surely sounds like your motherboard has a part opening under load, which would be very hard to find without having the spec's from the mfg. Net result would be get new motherboard.....

If you can try using ram, video card and cpu in another comp if they work then you know for sure its your motherboard, as you have already tried different P/S.

I have to say it does not look good for the m/b as far as I am concerned. But you cannot be sure till you know that ram,video card and cpu are ok....

Post back and let me know what you have done....

reny