John Woodgate wrote:

I read in sci.electronics.design that Terry Pinnell
wrote (in
) about 'PC CPU fan', on
Mon, 3 Oct 2005:

It may be coincidence, but I've only become aware of this since
installing a third HD - a 200GB Maxtor Diamond, 7200 rpm, in addition
to my two 60GB Maxtors.

Try loosening its fixing screws. If that stops the beat, tighten
slightly at random until the beat comes back. Reverse last step. Relax.

OK, will try that, thanks. As the tray has to be removed to get at the
screws, that potentially implies means a lot of rebooting though.

It's too soon to be sure, but I think I've made an improvement by not
using the 'locking knob' after attaching the side panel of this MESH
UK Athlon 1800 PC. The LF hum is still there, but it sounds almost
steady now, rather than beating.

I may also try some self-adhesive insulation of some sort on that side
panel.

--
Terry Pinnell
Hobbyist, West Sussex, UK