sharing a power supply

Alvin Oga alvin at
Wed Jul 2 17:51:44 EDT 2003

hi ya

hang a 100uf or 1000uf ( +50v or +100v ) electrolytic
capacitor across the mb power-on switch  to slow down its
power-on signal  ... or do a extra resistor-capacitor circuit ..

-- dont run 4 mb off one power supply.. you'd probably
   exceed the current output of the power supply
	- it will work.. it will just run hot and soon die

	( 1/2 life rule for every 10C increase in temp )

c ya

On Wed, 2 Jul 2003, Alan Ward wrote:

> Dear listpeople,
> I am building a small beowulf with the following configuration:
> - 4 motherboards w/ onboard Ethernet
> - 1 hard disk
> - 1 (small) switch
> - 1 ATX power supply shared by all boards
> The intended boot sequence is the classical (1) master boots off
> hard disk; (2) after a suitable delay, slaves boot off master
> with dhcp and root nfs.
> I would appreciate comments on the following:
> a) A 450 W power supply should have ample power for all -
> but can it deliver on the crucial +5V and +3.3V lines? Has anybody
> got real-world intensity measurements on these lines for Athlons
> I can compare to the supply's specs?
> b) I hung two motherboards off a single ATX supply. When I hit
> the switch on either board, the supply goes on and both motherboards
> come to life. Does anybody know a way of keeping the slaves still
> until the master has gone through boot? e.g. Use the reset switch?
> Can one of the power lines control the PLL on the motherboard?

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