Think I fried my mobo...electrical buzz sound coming from PSU

carl33p · May 12th, 2007, 01:12 AM

Place the mobo on a non-conductive surface, and only have 1 GPU, stick of ram, and CPU + HSF hooked up to a PSU. Short the power pins.

We will be able to narrow down the problem depending on what happens.

StealthyV · May 14th, 2007, 12:47 PM

I'll be testing this tonight, thanks all for your input!

The new psu automatically senses the voltage, and the old psu was correctly set at 120v.

Would any multi-meter work, or should I buy a specific kind? I'll be reading up on how to work the device, as I haven't used one since high school electronics class some 8 years ago!

StealthyV · June 7th, 2007, 08:15 PM

well...I found the problem.

the computer troubleshooting process has been shelved a few weeks, but I decided to tackle the problem this afternoon, after a couple glasses of 2003 Chardonnay.

After taking a flashlight to the problem, I discovered I had plugged in the 4-pin PCI-E power cable from the psu into my mobo's 12v 4-pin socket. Correctly connecting the designated 12v 4-pin power connector from the psu to the motherboard solved the problem.

doh!

thanks to everyone who replied; I did the "paperclip" trick on my old psu, and it's toast. luckily, there's a computer recycling center close by (Cromwell, CT) so I don't have to throw away the old psu.

problem solved!

~Branson

now, back to BF2 and CS:S!

*edit: and the original psu is still dead. it lasted me 4 years, and only cost me $54 new, so I think I got a pretty good deal, considering. The new psu is much quieter! and it's rated at "85% efficiency" so that's gotta be good, right?

DanU · June 8th, 2007, 03:15 PM

Are you sure it's the PCI-e power connector? That's a 6-pin connector.

JPMiller · June 8th, 2007, 03:50 PM

What new PSU did you get?

Jfrostt · June 24th, 2007, 01:47 PM

Hey all,

Sorry to dig up an old post, but I'm having this exact same problem with the difference being I can't quite distinguish if the buzz noise is coming from the bottom of the PSU or the CPU. The power LED on the mobo lights up when the PSU switch is on, and when I press the case power button, it makes that buzzing noise and all of the fans twitch briefly. After that the power button does nothing until I turn the PSU off/on again.

For me the problem definitely isn't the 4pin connector, as my PSU only has one of those, and my mobo is getting the proper 24pin cable, and the PSU is 450W which is sufficient enough to cover all my power needs. Also the voltage switch on the PSU is at its correct 115V position.

Also I've tested the PSU in another machine, and it works fine.

I'm afraid to try the basic boot-up by putting my mobo on a non-conductive surface, because there's the chance I might fry it by messing something up.

Also everything is hooked up correctly, RAM pushed in all the way, CPU placed in correctly, CPU fan tightly locked in place, mobo properly supported in place with those copper bolt thingys underneath it, power properly hooked into everything needing it.

Any ideas on what could be causing this problem?

Thanks!

KarmaKiller · June 24th, 2007, 01:57 PM

Hi there, Welcome to TIMO..

I would pull your motherboard out and put it on something Non conductive, and use only the bare essentials.(CPU,1 stick of RAM,graphics,PSU) Don't plug in any drives and see if you can get a post..
Also, you might post your system specs..

Jfrostt · June 24th, 2007, 02:47 PM

Ah sorry, forgot to post my parts:

Mobo: Asus P5N-E (775socket)
CPU: Intel Core 2 Duo E6600
RAM: Corsair 2x 1Gig sticks, DDR2, PC2-5300
PSU: Antec SmartPower 2.0 450W
Case: Antec Sonata II

Jfrostt · June 26th, 2007, 03:56 PM

Ok, I tested my motherboard outside of the case and here are the results:
-When I switch the PSU on, the green LED on the motherboard lights up

-When I use a screwdriver to short the power switch button pins to turn it on, there is the same electrical buzzing sound that persists for about a half second before stopping. The green LED stays on until I cut the power to the PSU. Also shorting the power switch again after this does nothing, until I cut the power to the PSU and turn it back on again.

-If I put my face close to the PSU fans, I could smell a faint burning plastic smell. I'm not sure if this is that new PSU smell or a something very wrong smell.

-The fans still twitch briefly when the power switch is shorted, so I'm guessing some power is getting through?

I'm about to try my current PSU in it to see if that works, but I'm not positive the PSU is the problem since it worked fine in another computer 3 days ago, before I had tried it in the one I'm building. Could it be something else in my computer causing the PSU to backfire or something?

I appreciate any help you can give me in this matter!

EDIT: On second thought I'm going to wait before trying my computer's PSU in the one I'm building because I don't know for sure if it's possible it is damaging PSU's - I don't want to risk until I know that isn't possible!

Jfrostt · June 27th, 2007, 12:52 PM

Anyone have any ideas?

EDIT: Just a random idea - I'm really reaching in the dark here - could it be the PSU isn't supplying enough power? If that's the case though, would it cause the PSU to make an electrical buzzing noise? It even does this if only the CPU/Heatsink are plugged in, which really wouldn't take much power I don't think.

I went ahead and tried my old PSU in it, but it doesn't have a 24pin ATX, just a 20pin ATX, so it wouldn't even get the fans to twitch or do anything. I also tried the buzzing PSU in my old computer, and it worked fine - no buzzing or anything.