mite be your video card fan
----- Original Message ----- 
From: "JMB" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, March 04, 2006 9:17 PM
Subject: Re: [PCBUILD] Buzz Sound At Bootup


> Okay, let me take a stab at this and give you some ideas.
>
> As I understand it, this is a physical noise from the computer and not 
> from the speakers, right? If it IS from the speakers, it could be related 
> to a bad ground on one of the many peripherals that are pluged into the AC 
> outlet strip. A bad ground can cause a ground loop current to occur - 
> which is not healthy for anything. Since the software is acting erratic 
> when the noise occurs, it is affecting the proper loading of the software, 
> which will mess it up. All three wire plugs should have less than 0.2 ohms 
> resistance between the ground pin and a metal part of the device.
>
> You have disconnected all CD-rom devices and any spare hard drives and 
> just have your boot hard drive connected. (While doing that, check each 
> power plug (four pin plug) for any pins that are pushed back. A faulty 
> connection can cause lots of trouble. Be sure to eliminate any other 
> peripherials you don't need for checking out this problem (printers, 
> scanners, etc.). You want a bare system (keyboard, mouse, monitor).
>
> You stated you swapped out the PSU with a KNOWN good one. Make sure it is 
> a known good one. Is it a new one? If it is an old one that was working in 
> another computer without any problems, it MAY be a good one. Since your 
> problem is intermittant - you really have to be careful with what you swap 
> in.
>
> On the motherboard, you may find a small, black round object, about 1/2 
> inches in diameter, with a tiny (1/16th - 1/32nd in.) hole in the center. 
> This is a speaker. Some motherboards have them, some do not. Is the sound 
> coming from the speaker? Test it during a noisy boot by putting your 
> finger over the hole. If it deadens the sound, then it is something in the 
> software/board that is causing the PC to generate the noise.
>
> Capacitors were mentioned. While a motherboard make look good, there were 
> problems with Electrolytic caps made since about 1999 (some cap 
> manufacturers stole a formula for electrolyte paste from a company and 
> used it to make their caps. Problem: formula stolen was incomplete - 
> therefore the electrolyte they made was bad, and large size Aluminum 
> Electrolytic Capacitors in many devices (PC Motherboards, PSU's, etc.) 
> were failing after about three years of use. Your computer may be outside 
> of the problem years, but just in case, look at the large size caps 
> (usually around the CPU) to see if they are bulging at the top or leaking 
> at the bottom (a brownish fluid or whitish powder). If so, you have a bad 
> cap problem (see www.badcaps.net). It may be contributing to a messup of 
> the software loading which in turn could be causing the noise problem.
>
> Do you have a battery operated toy recorder with a microphone (the kind 
> kids sing into - like a fischer-price or some other brand)? When you boot 
> the computer, with the recorder going, run the microphone in a gride 
> pattern around your computer (cover off) and as you go into certain areas 
> you can make a verbal clue (shout A, B C) according to your own plan. When 
> you play it back, listen for an increase in the noise sound and relate it 
> to where the microphone was (between C & D). That should help you pinpoint 
> the source. A toy recorder usually has a plastic case microphone so you 
> can get really close to things without worrying about shorting anything 
> out.
>
> And yes, the monitor can cause a problem an feed it back into the 
> computer. The electronics can handle some electrical noise, but not when 
> something faults and creates current loops.
>
> Hope these ideas help.
>
> Jean Bourvic
>
> Dan Deucalion wrote:
>
>>On Sun, 26 Feb 2006 15:26:50 -0500, Chris Ryan <[log in to unmask]> 
>>wrote:
>>
>>
>>>There's still one more moving part, the PSU fan. Can you briefly stop it
>>>
>>>from spinning (say, with a toothpick?) at bootup just long enough to rule
>>
>>>that out? Otherwise I'm thinking a capacitor on the MB is starting to act
>>>up. Have you left the case open and tried to listen during boot up to see 
>>>if
>>>you can pinpoint the noise?
>>>
>>>
>>
>>I swapped out the power supply so I know that wasn't the cause.  I remove 
>>the cover every time I boot up to try to zero in on the noise location. 
>>So far, no luck.  How would I be able to tell if a capacitor is faulty ... 
>>and would it be possible for the problem only to exist for 90 seconds or 
>>so at boot up?
>>
>>Dan
>>
>>        The NOSPIN Group has added a new feature on our website,
>>           web based bulletinboard for questions and answers:
>>              Visit our sister website at http://nospin.com
>>
>>
>>
>
>               The NOSPIN Group Promotions is now offering
>                 our special coffee mugs and mouse pads
>              with the PCBUILD logo...  at a great price!!!
>             http://freepctech.com/goodies/promotions.shtml 

        The NOSPIN Group has added a new feature on our website,
           web based bulletinboard for questions and answers:
              Visit our sister website at http://nospin.com