Power Leads and Splitting Cables

Posted by: waamatt

Power Leads and Splitting Cables - 09/01/06 10:35 PM

The power leads in an MDD PowerMac (like for the hard drives and optical drives) supply 12V, right? If fans use 3V, could you take a 4-pin to 4-pin Y splitter, connect it to 2 4-pin to 3-pin Y splitters and get 4 fans off of one lead, or would this be unwise?

I FINALLY ordered stuff to work on my machine, but if there's room, power wise, to add more I'll do so. I expect to have all the parts by the 8th, and then I'll be working on it that weekend. So, I'll clean the case, take photos the whole way through. Since I'm going to do the work at my parents' place I can use my dad's amazing digital camera.

FYI: I ended up getting a Sapphire Radeon 9800 Pro (256MB) from Newegg. It was out of box, so I'm going to slap it in someone else's PC to see if it works OK. If it has a 128k ROM (and how I hope it does), I'll get to use all 256MB of DDR memory on the thing. Otherwise, it'll only function as a 128MB card until I replace the EEPROM. Which really makes me wonder what's so special about those EEPROMs that no one seems to think it's possible to just go buy some generic, blank 128k chip (they must only come in a couple of sizes - rectangular or square) and flash it. Do EEPROMs get formatted like hard drives do? I guess I just don't know enough about 'em. I also ordered 2x1GB memory modules. I've never heard of the brand but it had plenty of positive reviews and really good timings, plus they come equipped with heat spreaders. Since I'm going to be acquiring another MDD soon (for $300!), I can put the RAM currently in my Dual 867 into the "new" machine. The fans, cables, thermal compound, sound dampening pads (for one part of the case) and chip heatsinks I ordered from SCV.com.
Posted by: Waragainstsleep

Re: Power Leads and Splitting Cables - 09/05/06 11:02 AM

I had a bunch of 80mm fans running off of two HD (molex) connectors. I think there 7 fans in total. No problems whatsoever. That was an AMD 1200 with a single HD, optical, reasonably decent graphics card and a 350W PSU. You may find you can;t have quite so many fans if you are running a stack of drives and other bits and pieces.
Posted by: waamatt

Re: Power Leads and Splitting Cables - 09/05/06 11:05 AM

Oh... Silly me. Fans require a 12V DC connection... So... Wait... How, then, is it OK to split the 12V lead to do two parts/components that each require 12V? Do they not really?

Oh, and by the way, almost all my parts are here, so I'll be doing my mods (all internal work) soon. One thing to note right away, which I'll go into when I write my mod article, is that the MDD's optical drive fan mounted to the door is not a normal fan. The mounting holes are bored out slightly larger than a normal fans'. I haven't checked to see if the main fan is also this way. Shouldn't be too hard to change, though, with the right tools (and I have or have access to plenty of tools).

My only concern is the size of my soldering iron. I might have to drop by Radioshack or somewhere and pick up a finer one. Anyway... Carry on!

War: I'm only going to have 1 optical drive, 1 HDD, a Radeon 9800 Pro, the RAM, and an AirPort card. Eventually I may add both a PCI-slot fan and a USB 2.0 port card (PCI, obviously). I'm going with 4 extra fans for starters. When I can come up with a fun way to mount a couple into the HDD chasis, I'll add a couple more.
Posted by: TCPMeta

Re: Power Leads and Splitting Cables - 10/24/06 06:09 PM

Why so many fans? If you add too many you will strain the power supply. Might want to try water cooling or get a higher wattage powersupply.

I had a PC that had 13 fans. They all ran off one molex connection but I built a special circut board for all of the fans to connect to and also had a fan controler installed.

You can always make the fans run at +5V too you know. May not be much in CFMs but it gets the job done.