Text 16936, 71 rader
Skriven 2006-03-28 11:05:00 av JAY EMRIE (1:123/140)
     Kommentar till en text av JEFF GUERDAT
Ärende: HD PW ?
===============

JG> JG>> It appears that desktop drives still  use +12vdc, probably for the
JG> JG>> spindle motor.   Laptop drives use only +5vdc for everything.
JG> JG>> However, in this case, switching the +5v line may be sufficient.  Of
JG> JG>> course,  it may require the +5v to  get the motor spinning  anyways,
JG> JG>> due to motor control circuits...

JG> JP>         Jeff, I guess that you have never seen a drawer for a HD. ???
JG> JP>    They have the connector end that looks exactly like a 3.5" HD. You
JG> JP>    connect the ribbon AND the 4 wire power cable. I remember looking
JG> JP>    at the red and yellow and they both feed into the inside connector
JG> JP>    where the 2.5" HD sits.

JG>I don't have any experience with the cheap models.  ;)  The hot-swap drawers
I
JG>used were for SCSI and fibre channel.

JG>Based on the pinout I'm looking at, it's not clear to me what would be used
to
JG>detect the switch and the removal/insertion of the hard drive. It may well
be
JG>that there's a buffer in the drawer someplace that would be used to keep
noise
JG>from reaching the IDE bus during removal/insertion as well as power.  The
JG>multimeter may be able to tell you or it may need further examination.  Can
you
JG>see the whole drawer or are there parts that may be covered and possibly
hide
JG>some circuitry?  I've never checked out how such a drawer works but I'd
rather
JG>expect some intelligence to not upset remaining devices on the bus as well
as
JG>the OS.

JG> JP>         Now, a retraction. I was asking if I could cut the ribbon on
JG> JP>    wires 1 and 2 to control the hot swap of a laptop drive. Wires 1
JG> JP>    and 2 that I was looking at were for the small 2.5" connector not
JG> JP>    the ribbon cable definition. The power for that ribbon is in
JG> JP>    parallel to it, physically, in that 4 prong connector where the two
JG> JP>    center ones are black ( ground ). I will have to look again when I
JG> JP>    get home. Maybe you have already implied that the 2P2T switch ought
JG> JP>    to be placed on that bundle ?

JG>Originally, the extra 4 pins were used for power but are apparently used by
JG>some manufacturers to be able to set master/slave these days since I haven't
JG>seen a device use the extra 4 pins for power in a long time. Since there's
no
JG>power spec'ed for the IDE bus itself, something must be onboard the logic
board
JG>to create sufficient current from the data lines, etc.  However, there's
also
JG>nothing stopping anyone from using those pins for power, AFAIK...

Jeff, I have, in my hands, one of the items in question- (that went
defunct).The part holding the HD has NO electronics what so ever. Only a
connector that mates with the connector on a small circuit board in the
carrier which is mounted in one of the external 5 1/4" slots.

This circuit board/connector does have minimal electronics i.e. 2
transistors, 4 resistors and 1 diode and normal connectors for HD power
and standard IDE connection and NO ICs. The switch in question has
only 2 wires, one black which I can see obviously goes to a Gnd terminal
marked -. The other goes to a terminal marked +. Now + what I can't
determine at present. Obviously the switch provides a voltage to the HD
when turned to the locked (on) position.

I hope my description makes a little bit of sense. Tis rather difficult
describing this item.
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