if you're only hearing them while scrolling the screen (and other
updates) the blips are bus noise from inside the case, radiated
from the expansion bus that the video card is connected to. if you
get them with a static image they are coming from the video card
or the monitor, a ferrite block over the vga cable coulkd help
with that.
I don't think so. The monitor switches scan frequency when going
from Windows to DOS. There is something in the monitor that creates
extra noise when scrolling. There is no noise on a static display.
There is nothing in the cable that knows what scan rate the monitor
is using at the moment. The blips do not occur at 1024X768, only at
640X480.
However, moving to a 5/8 wave vertical completely solved the
problem. There is no more noise on any frequency through the entire
FM band, even though the vertical is only a foot from the monitor.
This problem has plagued me for several years, and this is the first
time I found something that worked. Than you very much for
mentioning EMI in an earlier post. For some reason that triggered
the idea to try a different approach - and it worked!
add fans to improve cooling, or use punched covers (many small
holes)
That doesn't help when switching cards or checking for lint buildup.
Or discovering the cpu fan is seizing and ready to fail.
Obviously, if you are in an environment where screwdrivers, paper
clips, solder balls and coffee is flying through the air, you need
some protection for your computers. But I have a very benign
environment. I have no visitors to worry about, and everything is
open the way I like. The covers on computers just slow me down and
impede creativity. And that's a sin.
Do you know how difficult it is to replace the covers on a computer
after fixing it? I just spent 1/2 hr fooling with the covers on my
landlord's computer. What a pain. I'll leave mine off, thank you
very much
I do have a fan salvaged from the freezer section in a fridge that
mounts on the side of the computer during warm spells. It runs very
quiet and helps reduce crashes on hot days. But obviously it's time
to upgrade all the computers in the lab. And part of the new spec
will be reliable operation at elevated temperature
Regards,
Mike Monett
Antiviral, Antibacterial Silver Solution:
http://silversol.freewebpage.org/index.htm
SPICE Analysis of Crystal Oscillators:
http://silversol.freewebpage.org/spice/xtal/clapp.htm
Noise-Rejecting Wideband Sampler:
http://www3.sympatico.ca/add.automation/sampler/intro.htm