OT silent power supply update

["bfp" <bfp-at-earthlink.net>]

Hi All,

I've managed to hack the original Compaq power supply for silent running
here are some of the details
the original fan was a Nidec 12v .15a brushless fan and was connected
to +12v and a +5v health monitor circuit as "ground" return (it was already
fairly
quiet but had some bearing rattle) the health monitor wire showed +5v with
sharp
spikes to ground when the fan was running  and the supply would shut down if
the fan stopped spinning so I had to replace the fan load with a simulated
load

snip snip and out comes the fan in its place goes a small (1/2" dia)toroidal
transformer
(1:1) with series diodes (1N4001) 1 in and 1 out of the primary winding
on the secondary winding I put 2 more diodes out to a 68ohm 2w resistor then
2 more
series diodes back in to the secondary
don't ask me why but it works :-)

the modified supply is re-mounted more or less vertically in the case to get
a little
bit of a chimney effect and during testing it did not need any additional
heatsinking
the sides and top of the case and supply did not get noticeably warmer than
a standard
box with fans in place and it has not gone into thermal shutdown after
several hours
of running with a test program to give the cpu something to do

silent workstation specs so far are
Compaq Presario 486SX-33 with 12mb ram
2S,1P, ps/2 mouse&kbd ,hard&floppy drive controlers and svga on motherboard
1ea 1.44mb floppy for boot only
1ea ethernet card
running QNX demo disk for today working on a Linux floppy next

thanks again for the help on this
Brian