Re: GS Upgrade

[dempson@swell.actrix.gen.nz (David Empson)]

In article <22irqu$gbp@ausom.ausom.oz.au> peterm@ausom.oz.au writes:
> If the specs in the various manuals are to be believed, the GS power supply
> is the weakest of the three. Although they are different sizes the II(+) and
> the //e power supplies have identical spcifications. The GS has a slightly
> lower current rating. Probably because of all that CMOS on the board :).

According to my calculations, the IIe's maximum power output is 42.75W
(averaged over an hour, under 66% loading on the 12V rail at 2.5A, the
rest of the time at 1.5A), and the IIgs's is 36.25W.

However, the rails are biased quite differently: the IIe can supply
2.5A at 5V and 1.5A (2.5A intermittent) at 12V; the IIgs can supply 4A
at 5V and 1A at 12V.

The IIgs motherboard has a lot more 5V components, I assume - it is
probably there for memory more than anything else.  There is also the
Apple Desktop Bus, which can supply up to 500 mA to external devices
(this is in addition to anything that is equivalent to the IIe's drain
on the 5V rail).

I don't have any II+ hardware documentation handy, but from memory,
the II+ supply is very similar to the IIe's.

It looks like my earlier posting on the "weak power supply" in the II+
might have been premature.  :-)

I was surprised to note that the IIgs's 12V rail can only supply 1A -
the IIgs fan draws 350 mA (according to its label).  That doesn't leave
much.

-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand