Date: Sun, 12 Sep 1999 03:15:42 -0400 (EDT) From: Mike Nowlin <mike@argos.org> To: Kevin Day <toasty@dragondata.com> Cc: hackers@FreeBSD.ORG Subject: Re: damn ATX power supplies... Message-ID: <Pine.LNX.4.05.9909120310450.23083-100000@jason.argos.org> In-Reply-To: <199909120658.BAA43940@celery.dragondata.com>
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> Yeah, you're supposed to tie PE low when you want power... However, in a > system I'm working with now, we've discovered that some inexpensive ATX > power supplies don't expect to have PE come up immediately when they're > given power. If you see the symptom that all the LED's on your system dim > about 1-2 seconds after you give the power supply AC for a second or so, you > need to make a small timer circuit to wait 5 seconds or so before turning > the PE line on. Related info: if you have external devices (printer, and especially modem) attached, try turning them off and then applying pwr to the computer. In some of the cheaper systems we have around here, the modem needs to be turned off, or the computer flashes on for a second and then turns off... (486 boards, AT power supplies)... I did a bit of measuring, and on these cheap ones, some of the +12V from the modem serial lines gets leaked back into the power supply, causing it to wig out... --mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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