Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ucbvax!bloom-beacon!eru!hagbard!sunic!news.funet.fi!assari.tut.fi!assari.tut.fi!n67786 From: n67786@lehtori.tut.fi (Nieminen Tero) Newsgroups: comp.sys.mac.hardware Subject: Re: Help: IIcx powers itself down Message-ID: Date: 17 Dec 90 07:54:17 GMT References: <1192@dg.dg.com> <1990Dec8.010224.14756@cunixf.cc.columbia.edu> <110870@convex.convex.com> <111548@convex.convex.com> Sender: news@assari.tut.fi (USENET News System) Organization: Tampere Univ. of Technology, Finland. Lines: 47 In-Reply-To: woods@convex.com's message of 17 Dec 90 01:39:06 GMT In article <111548@convex.convex.com> woods@convex.com (Darrin Woods) writes: > BTW - for those of you who didn't catch it.. The socket on the back is > not a pass through - it draws its current from the mac itself just like > the hard drive and floppy and moboard > >Huh? Passing wall otlet power though the CX power supply. No way! There >might be a relay that the CX switches on when the machine is powered up >and so feeds power to the monitor, but that power surely don't pass trouhg >the CX power supply in any way. Check you facts. > > Tero Nieminen Tampere University of Technology (Opening Apple Technical Manuals - flipping pages) OK, I checked - unless one of my friends from Apple corporate would like to correct me, I state again. The power going out from the back of all Mac II's is directly controlled by the Power Supply - IT IS NOT A PASS THROUGH. The wattage that is stated on the back of the PS as being the max includes any power going out through the power connector to the monitor, HD or whatever. I guess you can always try it - Plug a hair dryer into the back of a cx and see what happens. Correct. A pass trough outlet would be one that is directly wired to the power inlet in the machine and it would pass power though regardless of wther the machine was on or not. The "directly controlled by the Power Supply" simply means that the power supply passes power through the outlet only when the machine is powered on. So there is some kind of relay cicuit that makes the connection, and I would allmost bet my head on it that it's a normal kind of electro-mechanical relay (of cource it could be a solid state relay, but I doubt that). And that relay is the one limiting the power draw from the outlet and it has nothing more to do with the power supply (relays do have their power ratings too, you know). As I understand the function of the computer power supply to be something more than just a relay, I don't see any reason to chance what I said before. The hd, floppy and mother board draw their current throught the power supply, but the monitor power is just switched on by the power supply. (BTW, what reason would there be to make it differently). Blacksheep Senior Systems Engineer -- Darrin R. Woods woods@convex.com -- Tero Nieminen Tampere University of Technology n67786@cc.tut.fi Tampere, Finland, Europe