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Thread: 3.5" floppy drive voltages

  1. #1

    Default 3.5" floppy drive voltages

    Hi,

    do 3.5" floppy drives require 12V power?

    I started to build a Z80 based system a few years back, but never finished any disk interface. CP/M runs off a ROM disk for now, which isn't that useful. But since I got an old XT FDC card recently, I wanted to add a 3.5" drive (DD only). Since everything runs off a 5V adapter, I won't be able to supply 12V - will that be a problem? A Gotek would work fine, but would a real drive as well?

    Also, since I am already planning to add two ISA slots to the system... where can I source those slots, or edge connectors in general? Is there a search term which would allow me to find them on Aliexpress or other sites?

    Thanks,
    Svenska

  2. #2
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    I am fairly sure that 3.5" floppy drives only used +5 volts.

  3. #3
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    Depends on the vintage. I have some NEC HH units that require 12v; some older Sony drives do as well. Haven't checked, but I suspect my 3.25" drives do as well--they're old enough.

    Card edge connectors are still carried by most of the mainline parts vendors (Mouser, RS, etc.)

    N.B. Edge connectors are subject to a rather strange terminology. A "10-position" edge connector has 20 contacts. Also, pay attention to the contact spacing; usually specified in fractions of an inch.
    Last edited by Chuck(G); June 17th, 2019 at 03:32 PM.

  4. #4

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    In my experience, they require 12V more often than not. But I'm not all that familiar with post-1980s PC stuff.

    You should have no problem finding a DC-DC converter to give you 12V from 5V. ISA slot edge connectors should be still readily available as well. Here's one (of many I found quickly) https://www.digikey.com/product-deta...3328-ND/927280

  5. #5
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    If you're talking about 1.44M 3.5" drives, none that I'm aware of; not even the earliest.

  6. #6

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    Quote Originally Posted by Chuck(G) View Post
    Also, pay attention to the contact spacing; usually specified in fractions of an inch.
    That is why I am asking, my last order turned out to be completely wrong.

    Quote Originally Posted by Chuck(G) View Post
    If you're talking about 1.44M 3.5" drives, none that I'm aware of; not even the earliest.
    I only have 3.5" HD drives, which are rather new (but will need to be run in DD mode). So my 5V supply should suffice.

    Thanks for the answers!

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