23 Nov
2003
23 Nov
'03
7:43 a.m.
On Sunday 23 November 2003 16:35, Vintage Computer Festival wrote:
I've got this 3Com OfficeConnect Dual Speed Hub 8
that is putting out
this obnoxious hissing noise. It's loud enough to be annoying and
add significantly to the white noise in my office. It sounds like
the air is slowly being let out of a tire...forever. I've opened it
up and found a capacitor with some brownish crusty stuff caked on the
top of it. It also was bulged ever so slight at the top, as was
another one right by it. Both are within proximity of the power
connector. I didn't see any blackened spots on the enclosure
indiciating that either had let out any magic smoke.
I'd replace those capacitors. Exploding caps don't have the same
visible effect as ICs or other components. I'm guessing the hissing
sound is from water in the paste/electrolyte inside the capacitors
boiling and coming out as steam.
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.)
Any help appreciated.
Pat
--
Purdue University ITAP/RCS
Information Technology at Purdue
Research Computing and Storage
http://www.itap.purdue.edu/rcs/