OT: hissing from a hub

From: Tothwolf <tothwolf_at_concentric.net>
Date: Sun Nov 23 18:23:06 2003

On Sun, 23 Nov 2003, Vintage Computer Festival wrote:

> So the question is, what is the most likely cause for this hissing? I've
> had a device before where the capacitor was causing the hiss (or at
> least I was pretty sure). There doesn't seem to be anything else in
> there that would cause the hissing (a bunch of ICs, a couple couls, a
> couple power transistors, etc.)

Sure sounds like the caps to me. US Robotics/3Com had the same problem
with some of the Courier V.Everything modems. I have several of those
modems that make that type of noise unless they have been left on for a
long period of time. One of these days I'll replace the faulty caps in my
modems...

Speaking of noise, if anyone has one of the older APC SmartUPS 900 units
(and possibly some of the other similar models), they also can make quite
a bit of noise. There is a coil in the 900s that start to whine with age,
and it can get quite loud. I haven't yet found a permanent solution to the
problem, but a little silicone seems to help.

On another note, I've not had much trouble at all with the high end 3Com
SuperStack hubs/switches, except for their low quality fans. I've pretty
much just started replacing those cheap fans with high quality types
before putting that kind of gear into production use.

-Toth
Received on Sun Nov 23 2003 - 18:23:06 GMT