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PC PSU connector types?

Discussion in 'Electronic Repair' started by Terry Pinnell, Apr 14, 2006.

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  1. My 300W PSU on my 4-year old PC has died. It was underpowered anyway
    (after adding extra HDs and a DVD drive) so I'm about to order a 400W
    replacement. My problem is that I'm not really clear about the
    specifications for the cable connectors. I see all sorts of
    descriptions on various web pages:
    5.25" Device Power Connectors
    3.5" Device Power Connectors
    Molex connectors
    SATA connectors

    "20-pin adapter for ATX version 1."
    5.25" Device Power Connectors : 4 + 2 SATA
    3.5" Device Power Connectors : 2

    Antec SmartPower 2.0 SP-450P 450W Active PFC PSU
    "24-pin power connector with detachable 4-pin section for backwards
    compatibility with ATX 20-pin motherboards."
    5.25" Device Power Connectors : 4 SATA
    3.5" Device Power Connectors :

    My dead unit has 5 connectors each containing 4 round sockets about
    2.5mm in diameter. They were powering my 3 hard drives, my CD drive,
    and my DVD drive. (A pair of wires also went from one of these to the
    rear fan.) Are these 3.5" connectors? Or are they what I see described
    elsewhere as 'Molex connectors'?

    My unit also has several other connectors, of which the only one being
    used was a small 4-hole one, a bit like a phone socket connector, used
    for the floppy. Is that what is described above as a 5.25" connector?

    My unit also has a few connectors that were not being used: a little
    4-hole one (2 rows of 2) which I *think* is described on some sites as
    needed for certain motherboards? And one with 6 rectangular holes. And
    a spare one like the one used for the floppy.

    I don't suppose anyone knows of a page showing labeled pictures of all
    these please?

  2. They are one type of Molex connectors, referred to as 5.25" drive
    connectors in this application.

    That is the 3.5" drive connector. The holes are on .1 inch centers
    like the pin sppacing on older DIP IC packages. They are also availible
    from Molex.

    It was the CPU power cable on some motherboards.
  3. Hi!
    Let's see if we can't break this down and make it a little easier.

    The "Molex connectors" you see discussed are the larger ones that have four
    holes in them. They are so named because Molex is the company who developed
    them (AFAIK). As you've seen in your computer, these usually plug into
    devices like hard disks, CD-ROM drives and some older floppy diskette
    drives. You'll have between four and six of these, and maybe more or less in
    some exceptional cases.

    The smaller rectangular four wire connectors are used for physically smaller
    drives, such as your 3.5" floppy drive. Some internal Zip drives use these.
    There are probably only two of these.

    As for powering the motherboard, you usually have two major groups of plugs,
    at least that I'm aware of.

    The first is a long rectangular plug that fits into a matching socket on the
    motherboard. This is the so-called "ATX plug". It is responsible for
    providing power to the motherboard. There is only one of these.

    The next plug is a four pin square. This plug has two rows of two pins each.
    It is used to power the CPU core on most motherboards. There's only one of
    these as well. It has all yellow and black wires going to it.

    Other plugs:

    The so-called SATA-plugs are long and very thing rectangular plugs often
    filled with little edge-connect pins. They're usually made of black plastic
    at one end.

    Your current power supply may have a few other wires coming out of it that
    aren't connected to anything at all. The ones that look like the "Molex
    plugs" or anything described above are usually for future expansion. (Don't
    be too surprised if you have extras--I've seen PC power supplies that had
    many more of these than could ever be used. I've also seen some with far too
    few for the case they were installed in.)

    Other plugs that don't fit any description above are probably just not used
    in your computer, and needn't be hooked up.

    Your best bet (if you don't mind shopping locally) if you're not sure what
    to buy is to head into a computer shop where the people know what they're up
    to and take your old supply with you. They'll know what you need and can
    explain things if you have questions about the plugs.

  4. "William R. Walsh"
    Thanks both, those have really helped. Also found a good picture here:
  5. Molex company makes lots of different connectors, including the power
    connectors for mobos and 3.5" hard and 5.25" drives (often wrongly
    called IDE power connectors for PATA drives). I don't know what 3.5"
    connectors are. Could they be for 3.5" floppy drives?
    The 4-hole one is for extra +12V power for certain mobos. The 6-hole
    one is probably for high-performance graphics cards.
    Here's a guide to PSUs that includes descriptions and photos of the
    various connectors:

    It also lists good and bad PSUs, but in its list of good ones the best
    are probably Antec, Seasonic, Fortron-Source/Sparkle/Hi-Q/PowerQ/Trend,
    Zippy-Emacs, and PC Power & Cooling. I don't know about all the other
    brands, like SilentX and Silverstone, but you may want to look for
    Fortron (most model numbers start with "FSP") because they're not only
    good but also cheap. Thermaltake/High Power/Sirtec isn't the best.
    Other good brands are Delta and Lite-On, which in the U.S. are rarely
    sold on the retail market, and Channel Well, although for the latter
    you have to be careful because their quality is all over the place, and
    you want only those that are like the Antec SmartPower and TruePower,
    their "B" and "A" suffix series, i.e., CWT-350BSP, CWT-430ADP ("S" =
    single fan, "D" = double fan, "P" = power factory corrected).
  6. Great, thanks Larry.
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