ok , dunno if this will help.
i once had 2x 300 watt psu's in my amiga (both was atx)
why? , because my hdd's keept falling out (u know the sound) ..
so i added one more (and my miggy is pretty souped up).
i had 2 psu's...belived that would cure my problems..., and sure it did until the weird things started to happen.
THE fan on psu 1 died, just stopped to rotate (it was powering a hd and 2 fine..
so i replaced Psu1 with a new one.
Then Fan on PSU 2 died , just like psu 1 did , so then i belived that having 2 psu's in one tower aint a good idea.
but i got another psu. and a few months later both was dead.
note that psu 1 got replaced by a new one and the new one didnt die until after psu 2 had died.
any connection? .
i use the atx converter for the RBM towerhawk.
anyway i never blew any psu with the adapter when i had 1 psu connected.
later on (now) i use 1x AT psu as i removed my atx stuff when i got an mediator , i tried with 2 psu's now also, but the psu dies (fan stops to rotate)
(and it max deliver powerenough for maybe 2 hdd's ... or else it will just die....crap)
maybe its of the same problem? , system not meant to be powered like this? , maybe its the tower GROUND ? ...oh well i dont know and i find it very mysterious.