Intermittent power issue

[Kean]

(specs @ bottom)

I'm hoping someone can help me with an issue I'm having with my system (provided you have the patience to read my lengthy post). Problem.....Power. I built my system back in February 2002 and the problem started in late April. Computer will react one of three ways:

1) Upon start up the lights (HDD & pwr) will flash on, fans will spin, and you hear the click of the power turning on but the system will immediately power off. This happens in an instant (little less than a second).
2) If the computer makes it past that point, it may power down at any time with no warning. The only difference is that the power light begins to steadily flash (as if it were in "stand-by" mode) with no way of resuming.
3) Computer powers up. has no problems for hours, and will power down without any incident either.

In the first 2 instances you have to shut off the power source to the PSU, wait for the green LED to turn off on the motherboard (approx 30 seconds.....I never timed it), and then you are able to try again. I continued using my system (when I could) and attempted to diagnose the problem as I went.

Here is a list of the things that occurred during the period of my "power issues":
- Reflased bios from 1005 to 1006 beta. Still had issues.
- A couple weeks later I began having strange video-like issues. The screen would freeze and display odd characters or on-screen anomalies. This continued until the only thing I got was the post screen and then a "_" cursor in the upper left hand corner of the screen.
- I had already made the purchase of a GeForce 4 card and took the time to install that (just in case the issue was related to my existing GeForce 3 card). The system booted up and it took me a little while to tweak the drivers and settings for the card to work as I wanted. However, the freezing problems continued. I thought it may be the O/S so I did a re-format and a re-install of Win98SE. This worked for awhile and I upgraded to WinXP in the meantime.
- Later that same week, my HDD began to make a random "tocking" noise when it was trying to access data (the same noise as when the arm goes to the resting position during shut-down). This was progressively worse as time went on. It got to the point that it would not even get past the welcome screen. I checked all connections to make sure it wasn't due to an intermittent power connection. As a last resort I took the HDD out and installed it in my girlfriend's computer that I built for her. It made the same noise. HDD failure.
- Confident that I discovered the cause of all of my problems (intermittent power issues included), I made the purchase of a new HDD (see above specs). I loaded WinXP, drivers, programs, etc. I had no problems for a week.
- Last night I went to turn on my computer and it immediately turned off again. DAMN!!!! Same issue!!!!!

During this whole time I've tried connecting the computer to different outlets, checking the power connections, taping unused molex connectors, remounted the mobo (checking for likely short circuits on the back), and unplugging fans, CD-RW, etc. A new 1006 bios version is available but I haven't refalshed it in fear that my computer might shut down in the middle of the process. Anyhow, I've come to conclusion that it's either my motherboard or the power supply. Any ideas? I'm hesitant to continue using my system since I'm not sure the problem caused the failure of my last HDD or it was just a coincidence. Any help would be greatly appreciated. Here's my system:

- Asus P4T-E (bios rev 1006 beta)
- Intel P4 1.6a (with stock heatsink)
- Maxtor Diamondax Plus D740x HDD 40gb (connected as primary IDE device)
- 2x 128mb Kingston 800 RIMM's (and 2 continuity modules)
- HP 9110i CD-RW (connected as secondary IDE device)
- Enemax EG365P-VE FMA 350w
- Lian-Li PC-68 case
- WinXP Home Edition (fresh install)
- Visiontek Extasy 4600Ti GeForce4
- Viewsonic 21" P815-4 monitor

Replaced/Upgraded from these parts during the time I had this issue:
- Visiontek GeForce3
- 20gb Maxtor Diamondmax Plus D740x (problems with noise and access)

thanks,
Kean

[ktkendall]

What wattage is your power supply???

[ktkendall]

I see it there now, as long as PS is enough watts, I would think the Mainbord may be defective! I think 350 is good, but isn't there an extra connection for power on the new P4 boards? Maybe someone else has built one recently, I've seem the P4 power supplies out there that have some kind of auxillary connection to the motherboard for power along with the main connector!

[Kean]

350w

[Kean]

There's the main, aux, and a special 4 pin "ATX 12v" connector.

[Cricket]

Hi Kean,

One thing you can try is booting the system from the motherboard instead of the front panel. Remove the power switch connector from the motherboard front panel header and then jump the two pins with a small screwdriver to try to start the system.

If you PC starts every time with no problems, you might have a sticking power switch. Also check that the reset switch is working properly.

If the computer doesn't start up every time, I would swap in another power supply to test with. Although Enermax is a good brand, the power supply could still be defective.

If your system still doesn't power up properly, then my guess would be the motherboard power circuit is bad.

You might also want to try starting the system with the motherboard out of the case, just to eliminate any chance of the motherboard shorting out against the case.

You might also want to try different sticks of RAM if you can get ahold of some.

Cricket

[Kean]

Thanks for the response. My thoughts were the same regarding the power button (I tried it). I also tried to unplug, move, jostle any piece of hardware I thought might be causing a short. I haven't tried starting it with the mobo removed though. The probelm with swapping the PSU is that I have no extras of the ATX 12v. I may have to resign myself to the fact that I will need to get one (maybe a 400w so I can add some mods and more equipment). I just wanted to see if anyone thought the problem sounded more like a PSU issue than a mobo issue. Also, you never know if someone will come up with a simple solution you never thought of. It's never hurts to ask. I appreciate your input.

Thanks,
Kean