Presario power supply dies when m/board plugged in:-0

[news_shooter]

Having a strange problem with my Compaq Presario/AMD Athlon (1.5 yrs old). As long as it's running, everything is fine. But, if you shut it off, for any reason, and pull power, even for an instant, it won't restart.

Looking at the power supply on the back, I noticed that the power led (on the power supply) was blinking intermittently. So, I plugged in a spare (working) supply, to no avail. But, I put AC back to the old (still installed) supply, and the light came on.

Through trial and error, I learned that, when the motherboard power connector is plugged in, the computer simply won't start (no lights, no noise, NOTHING) and the power supply led blinks. But, unplug that, and the light is on.

Just to see I tried plugging in the motherboard cable with the AC connected. Okay, not the brightest thing to do, but I wanted to see, and sure enough, as soon as you plug in the connector from the motherboard to the power supply, the light goes to blinking. Note that it's not like an "error code blink", just an intermittent flash of varying intensity.

If you plug and unplug the AC cord a few times (tried 2 ac cords to eliminate that problem) the light will finally stay on, and the computer will work fine, until the next power flash.

I figure I can either puzzle this out, or just go buy a battery backup:-)

TIA
Jim

[Thong_Ispector]

First of all STOP DOING THAT...
You will blow up something important.

Although a year and a half isnt old I would check your cmos battery, replace it if at all questionable.

What was your original power supply rated at?
What was the rating on the power supply you tried?

Did you add anything to the original configuration, drives, ram, or upgrade the video card?

[news_shooter]

The original was a 250 watt p/s, while the replacement was a 400 watt. I hadn't thought about the cmos battery, I wonder if that could make it do this-well, it won't be too hard to replace that.

Nope, I hadn't changed anything from the stock configuration. I'd added a Pinnacle capture card the day I got it, and hadn't done anything since.

I know that doing the "plug it in" stunt isn't the brightest, but it's not likely to damage the hard drive itself, and I figure the motherboard is already toast. I found a direct replacement motherboard online for seventy bucks, so that's my first inclination.

[Thong_Ispector]

A direct replacement would not be my first choice.

For about the same money you can get a new case with power supply and a new MB that will take your CPU and other components.