Date   : Fri, 16 Jan 2004 00:28:11 +0000
From   : Richard Gellman <splodge@...>
Subject: HD Powre Consumption

Someone previously was asking about power consumption of hard drives on 
startup.

While doing a little research on Seagate's site regarding the power 
usage of a 500Mb ST1480N SCSI drive (I have one here that I planned to 
use) it turns out said drive uses around 0.54A on the 12 and 5 volt 
lines while running, but its startup 12V current is a whopping 2.5A!

Checking on the underside of my Master 128, the aux power connector 
rates 12V at 1A and 5V at 900mA. I think connecting that drive might fry 
the PSU somehow. An external power supply is definitely going to be 
necessary.

Anyone have any quick n dirty ideas for a BBC-turns-on-PSU circuit?

-- Richard Gellman