Path: utzoo!news-server.csri.toronto.edu!rutgers!mit-eddie!uw-beaver!zephyr.ens.tek.com!gvgpsa!gold.gvg.tek.com!grege
From: grege@gold.gvg.tek.com (Greg Ebert)
Newsgroups: sci.electronics
Subject: Re: IBM Power Supply - quick question
Message-ID: <2059@gold.gvg.tek.com>
Date: 11 Mar 91 17:15:37 GMT
References: <1991Mar10.173827.1690@ncsu.edu>
Distribution: usa
Organization: Grass Valley Group, Grass Valley, CA
Lines: 17


 bcasper@eos.ncsu.edu (BRIAN  CASPER) writes:

>I'm building a project and using an old XT power supply for a source.
>
>On P8, I think pin 1 is labeled "Power Good".  What is this for?  Do I need
>to loop it back into ground or something to keep the PS from shutting down
>or something equally bizzarre?
>

'Power_good' is just that... It's a TTL-level signal which goes high when the
supply outputs are stabilized. It ties into the CPU reset signal.

Some power supplies require a _minimum_ load before the voltages come up, so
if you measure them unloaded with a meter, you get near-zero readings. I have
seen load resistors which plug into systems without hard disk in order to
satisfy the minimum load requirement of the power supply.