Date: Tue, 26 Nov 1996 12:25:00 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: dkelly@hiwaay.net (David Kelly) Cc: hackers@FreeBSD.org Subject: Re: Holy Moley Batman... I love ccd. and BTW, if you need 4gb d Message-ID: <199611261825.MAA17332@brasil.moneng.mei.com> In-Reply-To: <XFMail.961126075034.dkelly@hiwaay.net> from "David Kelly" at Nov 26, 96 07:42:17 am
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> >> Anybody know of a source of these power connectors? > > > >I think DigiKey. > > Looked. Haven't called. Also checked the Mouser catalog. Would you > believe neither lists *any* standard HD/Floppy power connectors? Bullch.. uh.. wait. You're right. :-/ DK does carry drive power splitter cables but not the connectors themselves. AE-1027-ND Power Cable for 2 - 5 1/4" Drives claims to be two meters long, which if it is true might still be very practical. At $1.98/each I think DK is probably full of $#!t. Wouldn't hurt to call, though. At that price it would be just as easy to cut 'em up and not even worry about having to crimp the pins. My Molex catalog lists them though, exactly what you wanted as a matter of fact... Disk Drive Power Connection System 70156 Series Female Connector ... insulation displacement ... feed thru or feed to ... Available with red, blue, or black caps :-) Let me know if you want Molex order numbers, I can give you details. They also have the 8981-4P crimp housings that you normally see used on PC power supplies. > >But you do NOT want to do this, I think! > > > >I strongly suspect that you will find that the voltage at the end > >of your "power bus" will be sufficiently less than the power you are > >feeding into it... you would be better off getting a bunch of old > >power supply leads, connecting them all to a 4 pole barrier strip, > >and feeding them that way. > > > >I am sure someone will tell me I am wrong ;-) > > Actually I'm more concerned about the power supply driving 5 or 6 > hard drives. This is probably near the design limit of what should > be a 60W power supply. Three of my drives are labeled "8 watts". > Say each pulls 1.5A on the 5V line, the voltage drop on 18" of > 18ga at 7.5A or 9.0A isn't going to be much. OTOH thats getting > to be a bunch of current. Don't do it! A 60W PS can handle MAX of two 3.5" drives in my opinion and experience, and trying to handle more might work but might also end up with flames shooting out of the power supply. Worse, a 60W PS is typically a cheap unit and may not overload properly, and end up delivering inadequate voltages or current to the drives, which may damage the drives. > Not sure if these drives support "spinup on demand" or not. Am > fairly sure the PS won't tolerate all drives trying to spin up > at once. :-) Absolutely not. I would be impressed if you could even get all of them running at all. I certainly would not want to do it on my equipment: I would lay odds on something bizarre happening. > Also keep in mind this isn't a serious task. These parts are laying > around and I'm going to see what I can do with them. Get a cheap PC power supply. My nice 6-bay 3.5" disk towers have 300W power supplies in them and they are clearly more than adequate. But I can not imagine being able to run even six very efficient drives on 60W, that is 10W/each. "Fat chance". ... JG
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