While not recommended you can also consider removing the ground connection to the pre-amp to test and see if you have a ground loop somewhere.... if it uses a standard IEC cord, the easiest way is to just break off the round ground contact on the cord.. they are a dime a dozen.
-sc > -----Original Message----- > From: John Aldrich [mailto:[email protected]] > Sent: Tuesday, April 20, 2010 9:01 AM > To: NT System Admin Issues > Subject: RE: OT: HP/Compaq NC6120 laptop noise > > Just out of curiosity, have you tried a USB mic? That might bypass whatever is > causing the hum. > > > > -----Original Message----- > From: Peter van Houten [mailto:[email protected]] > Sent: Tuesday, April 20, 2010 8:02 AM > To: NT System Admin Issues > Subject: Re: OT: HP/Compaq NC6120 laptop noise > > Thanks Daniel. The nc6120 does not have an internal mic but the noise is > produced whether an external mic is plugged in or not. This is verified by > using the sound recorder or running Skype. It is beginning to look like > oscillation produced in the mic preamp section. I was hoping that someone > else had seen something on this and could point me to a quick fix but it is > looking like a laptop strip :-( > > -- > Peter van Houten > > > Daniel Rodriguez wrote the following: > > Is this happening with the internal mic or an external mic when it is > > plugged in? > > > > On Mon, Apr 19, 2010 at 7:00 PM, Peter van Houten <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hello all, > > > > We have recently upgraded several of these laptops at a client. The > > machines are old but not too badly specified, so it was decided > > to upgrade to the max. The RAM to 2GB, the disks to 320GB and the > > O/S > to > > Windows 7. The users were delighted and all was well...except for an > > audio problem. > > > > It occurs when recording sound from the mic input. Skype can > > trigger > the > > situation and is the application that uncovered the problem. It is a > > continuous, low-level, [approx.] 500Hz whine (groan?) It is not a > > feedback problem :-) The user couldn't hear the noise but the > > people on the other end of the conversation were complaining. The > > problem doesn't occur when simply playing audio, so it hadn't been > > noticed previously. > > > > First test was to check a laptop that had not been upgraded. That > > returned exactly the same fault. After that, we booted from an > > Ubuntu > CD > > to rule out the O/S and drivers and the same problem occurred. So, > > it > is > > hardware related and before we open one and start testing for bad > caps, > > ground loops and crispy spiders, has anyone else seen this? > > > > I have searched endlessly and found one *similar* problem on the HP > > forum with no resolution. I am an electrical engineer and equipped for > > (and comfortable with) all manner of hardware down to smt but I am > > getting too old for this! > > > > TIA > > -- > > Peter van Houten > > > ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ > <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ > > > ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ > <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
