[GTALUG] a quick question about power supplies?

[Lennart Sorensen]

On Thu, Jul 18, 2024 at 12:19:02PM -0400, Karen Lewellen via talk wrote:
> Hi wise souls of computing.
> One of the creative problems going on with my recently built computer is
> that the fan in the power supply no longer works.  Nor can I use the power
> button to actually turn off the machine anymore.
> When it gets too warm in fact, I must flip the switch on the supply in the
> back..its scary, but so is overheating.
> 
> While I am still hunting for sighted help to fix the mess my prior contact
> left behind..the cd rom is disconnected too, I want to plan properly for the
> power supply replacement.
> I have several, including at least one still in the box.
> I am quite sure that the power supply capacity is too low for the several
> things the machine is doing, I have three hard drives in the unit, several
> internal boards in use those kinds of things.
> Is there a guide, or rule of fun, for  determine how much power capacity a
> supply should provide based on how much work the computer processor will be
> doing?
>  With appreciation.

So for old spinning hard disks (not modern solid state drives), power
consumption is usually in the 5 to 10 watts, but could be 15 watts for
some of the older ones from 25 or 30 years ago.  Not sure which ones
you have in this machine.  But worst case call it 50 watts for 3 drives.

Pentium 3 processor at 1GHz is up to 35 watts.  A couple watts per stick
of memory if I remember right and a bit for the chip set on the board.

It does not seem like that should overload most power supplies.  I think
power supplies under 200 watt were pretty rare, although I am sure Dell
would have tried to put a 180 or even 150 watt power supply in a machine
to save a few dollars.

If the fan has failed, that will definitely make the power supply
unhappy and the heat could very wall make it less stable at managing
the voltages too.

Is the cd-rom internal or USB?  You mentioned a DOS USB driver (looks neat,
I had no idea someone had made that) so maybe the cd-rom was an external
USB.

-- 
Len Sorensen