PC won't turn on - PSU or MoBo?

Computer Forum Power Supplies and UPS's
1

Micron PC, ATX, Pentium 2GHz, Delta Elec 300W PSU.

PC started going into standby at random times even if I was actively using the keyboard and it was not recoverable by normal key press/mouse move or even with power button press. I had to unplug the power cord for 10 seconds, plug back in and hit the pwer button to restart the PC.

Now the PC will not start at all. The green light inside the case on the MoBo comes on when the power cord is connected but the main green LED on the faceplate does not come on when the power button is pressed. Instead the orange standby indicator turns on. I can turn that off only by pulling the power cord or by holding the power button down for 5-10 seconds.

So… does this sound like a PSU issue? BTW, I tried the “ATX reset” procedure described here to no avail.

Thanks for any assistance.

Ray

2

I’ve done a bit more troubleshooting. I pulled the PSU and jumpered pins 14 and 15 as per this instruction and got no response.

Test ATX Power Supply

So my guess is the PSU is dead. Does this sound logical? I’ll probably pick up a new one tomorrow and give it a try.

3

Yeah, that definitely sounds like a PSU going out. Power up problems that aren’t consistent? Check. Oddities happening at random? Check. PSU not powering up on it’s own? Check. Sure, it could be the motherboard, but the symptoms support a dead/dying PSU.

4

Thanks for the feedback B. I’ll pick one up soon and give it a try. 20 years of owning PCs and I’ve never had one of these die. It’s always something!

5

There’s always a first time for everything. :wink:

6

Ain’t it the truth! I picked up an Antec 350W PSU at CompUSA, dropped it in and the PC booted right up. As PC problems go it was a very easy fix. I got the Antec instead of a cheaper unit because of the lesser fan noise. But it turns out that the case fan is the real noise culprit. I wonder if there a quieter replacement for that?

7

Yes there is. There’s several different sizes and you’ll have to find that out. The typical sizes in cases are 80mm and 120mm. There’s a few 90-92mm out there, but it’s usually the other two I mentioned. The RPM of a fan is a good way to determine the noise. A higher RPM, obviously, spins faster, and are generally going to be noisier.

Without modifying your case, you’ll be limited to what size is there, and to find that out, you’ll have to look. Antec fans are commonly available at Best Buy and Circuit City. However, I’ve found them to be a little expensive, so check a local PC shop to see what prices they have. An 80mm fan runs around $10. You might find some online, but with shipping, it might be more expensive.

For some quite fans, you’ll want to look for Panaflo (by Panasonic) or Vantec’s Stealth line.

It may be that your current fan is just old, so you probably don’t need to be too picky if you’re not too particular about noise.

8

I figured they came in standard sizes. Mine is easliy accessible and I’ll measure it one of these days. The noise isn’t that bad and the bearings and motor are fine. The noise is strictly due to the high rpm of the fan blades. If I can find a quieter one in my size I may try a swap one of these days. Thanks for the info.