dmurdoch@watstat.waterloo.edu (Duncan Murdoch) (11/06/90)
I've got a Northgate 486-25, and have noticed that under certain conditions, when it's in a loop asking for input I can hear a high pitched ringing (maybe 8 KHz, but I'm not a very good judge of pitch). For example, if I boot with almost no drivers or TSRs except Borland's TDH386.SYS (the driver for virtual debugging), I can hear the ringing when I'm at the DOS prompt, and it becomes much louder after I've run the debugger and exited. If I run a program, or just do a DIR, it stops until I'm back at the prompt again, so I think it must be that I'm hearing the CPU (or some associated circuit) resonating at the frequency of the input loop. Does anyone know whether this is a sign of an impending breakdown? It seems to me that the CPU (if that's what it really is that's vibrating) shouldn't vibrate enough to emit sounds, and if it does, is likely to work itself loose from the socket. Duncan Murdoch dmurdoch@watstat.waterloo.edu
donm@hpnmdla.HP.COM (Don Montgomery) (11/09/90)
Are you sure the ringing you're hearing isn't coming from the pc's speaker?
Depending upon how the speaker is driven, it may be digital noise being
coupled into the speaker-driver circuitry, with the pitch and volume de-
pendent upon bus activity.
I have a Heath Computer Voice Card (with its own speaker) in my '286 machine
that makes all sorts of interesting "space age" sounds due to bus activity
coupling into its audio circuitry. Not loud, but enough to make a guest
user wonder what's going on...
Don Montgomery
donm@hpnmdla.HP.COMpel@pan.ctron.com (Paul Leclerc) (12/20/90)
In article <1990Nov5.210559.5733@maytag.waterloo.edu> dmurdoch@watstat.waterloo.edu (Duncan Murdoch) writes: > >I've got a Northgate 486-25, and have noticed that under certain conditions, >when it's in a loop asking for input I can hear a high pitched ringing I have the very same condition on my old 286 clone with EGA and with a monochrome monitor. I notice it especially with the Emacs editor called Epsilon. Almost no other program does it. >(maybe 8 KHz, but I'm not a very good judge of pitch). For example, >if I boot with almost no drivers or TSRs except Borland's TDH386.SYS (the >driver for virtual debugging), I can hear the ringing when I'm at the >DOS prompt, and it becomes much louder after I've run the debugger and >exited. If I run a program, or just do a DIR, it stops until I'm back >at the prompt again, so I think it must be that I'm hearing the CPU >(or some associated circuit) resonating at the frequency of the input >loop. I think it may hav eto do with the high intensity chars (ie real bright). >Does anyone know whether this is a sign of an impending breakdown? It >seems to me that the CPU (if that's what it really is that's vibrating) >shouldn't vibrate enough to emit sounds, and if it does, is likely to >work itself loose from the socket. Ieeee!!! I hope not. I don't need another computer breaking down right now. Paul L. pel@ctron.com