poulin@POLAR.BOWDOIN.EDU (Jeff Poulin) (12/08/90)
Sorry to keep bothering you folks, but my PC *still* makes those high pitched noises. I don't know what's causing it, but I do know what isn't. It isn't the hard drives, the fan, the PC speaker, or the modem speaker. I had all of these unplugged yesterday and the computer still made those "squeaks" (almost like bird chirps). It sounds as if it's coming from the power supply, but at this point I'm too miffed and frustrated to draw any conclusions. Any more help is greatly welcome. -- Jeff Poulin poulin@polar.bowdoin.edu jpoulin@bowdoin.bitnet
stank@anvil.WV.TEK.COM (Stan Kalinowski) (12/11/90)
In article <9012071856.AA07544@polar.bowdoin.edu> poulin@POLAR.BOWDOIN.EDU (Jeff Poulin) writes: >"squeaks" (almost like bird chirps). It sounds as if it's coming from the >power supply, but at this point I'm too miffed and frustrated to draw any >conclusions. Any more help is greatly welcome. I have "heard" switching power supplies under two circumstances. One is a sort of chirping effect when the power supply goes into it's over-current shutdown mode, the other is simply changing high frequency clicks as some program runs. In both cases I believe the source of the noise is the torridal core in the power supply itself. Typically the windings work a little bit loose and then start to vibrate under changing loads. The chirping effect is usually associated with a short on one of the supply voltages. The high freq. clicks are usually associated with some sort of cyclic high bandwith activity, scrolling text, or zeroing ram, for example. In fact the workstation I'm using right now does it when I scroll one of my X-windows. stank US Mail: Stan Kalinowski, Tektronix, Inc., Network Displays Division PO Box 1000, MS 60-850, Wilsonville OR 97070 Phone:(503)-685-2458 e-mail: {ucbvax,decvax,allegra,uw-beaver}!tektronix!orca!stank or stank@orca.WV.TEK.COM