Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

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Is it possible to connect a 2.5in drive into 3.5 in cable on a
standard motherboard?

There are some adapters that convert between 2.5 and 3.5 in

What I'd like to know if it is electrically safe to do so?


Re: Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

vfclists wrote:
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I've run the smaller drives using an adapter and did not see any
problems.  I believe the adapter compensates for the differences


Re: Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

vfclists wrote:
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Since the difference is purely mechanical, you should have any problems
with an adapter of suitable quality.  I've use one like this:

Re: Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

Grinder wrote:
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The 2.5" IDE is a 40 pin standard section, plus four more pins,
of which some are used for power. Both drive types would have
+5V available for a logic supply. The connector styles are
different, in that the center to center spacing of the pins
on each connector are different. The adapter Grinder linked to
above, converts between the two center to center pin spacings,
and also brings out the power pins, for connection to a power supply.

A 2.5", runs the motor and logic off +5V. The power is relatively
low, which is why some 2.5" drives can run off USB bus power.

A 3.5" uses +12V for the motor and +5V for logic. The peak
12V current is pretty high, at 2.5 amps on some brands. The
idling power is lower than that. Bus powering via USB or Firewire,
for a 3.5" drive, would be problematic. One Firewire solution
tried, was the idea of storing up power, so that a
ten second surge could be provided to get the disk to
spin up. But generally, a 3.5" drive needs a serious
power source, to operate properly with no issues.
The 2.5" drive has lower power requirements, making
more powering options possible. (Some 2.5" external
enclosures have two USB connectors, to provide
slightly more than 2.5W total power, while others
for more modern drives, can get by with one connector.)

The 2.5" drive may have a separate section with pins on it,
for setting master or slave. On a few laptop optical
drives, there are no master or slave pins, and the
master or slave setting is actually determine by
firmware load. Which is one stupid "innovation".
Jumpers make the job much easier, for general usage
by end users. The firmware technique only suits mass

In this picture, the 4 pin jumper area is on the left, and 44 pin
connector section is on the right. And the 44 pin part is
40 pins interface plus 4 for power and other functions.
(I have no idea what the TYPE pin options are...)


Re: Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

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you can get both PCB style ones, and Cable ones.

I use the cable ones. Because PCB ones have a funny design. With the
PCB ones I can't get the drive to be flat on a surface.

I just did this search on
2.5 3.5 ide cable -usb -usb2.0

That picked them up

A similar search on google images found a pic

All these 2.5 - 3.5 adaptors (adaptors for plugging 2.5" drives into
3.5" IDE connectors) are only unsafe in the sense that any time you
plug a 2.5" drive in, if the connectors can go on both ways, then you
can break the 2.5" drive.
And many techies even have done it.

A bit of background..
HDDs and MBRDs , the IDE connectors are MALE.
They are connected together by a cable Female at both ends

The 2.5" IDE connector is smaller than the 3.5", but has more pins/
holes. 44-pins/holes.
The 3.5" IDE cable is bigger but has less pins/holes. 40-pins/holes.

The 2.5" drive takes its power in its 44-pins.
Looking at my adaptor cable's 2.5" connector, it does it in 3 of the
holes(holes 41,42,43). It has 3 red wires one black wire..  Pin 44 has
no wire going through it.

So.. Of those extra 4 pins/holes, the power is there. Those wires(2
red one black) are on hte end of the cable.. So you have red wires on
the end of the cable.
They are on the 40s end of the cable.

And there is a SERIOUS problem psychologically with that, that can
cause human error.

Pin 1, with the red stripe.

We identify RED as pin 1.

The most striking red, is the red wires of the power.

So that's mistake number 1.. That one could make.  And end up
connecting the cable the wrong way.
That mistake is with connecting the cable the wrong way.

There is another mistake.. a huge one, people can make

Instead of looking at the cable, look at the 2.5" drive now

that 2.5" IDE pinout is fine.

You see those pins adjacent but separate to the IDE connector.
They are 4 pins.

They are actually jumpers, as the pinout shows.

But Somebody could easily not have it crystal clear in his mind that
the power is within the IDE connector.  They could associate the power
with those pins. And, as with 3.5" Drives, they would say, well, pin1
of the cable aligns with the power pins!!!!!!   (those are actually
jumper pins, and they would be right that pin1 aligns to them - though
they are jumper pins not power pins)

But They might then go and plug the Power side of the cable alongside
them. After all, they kind of associate them with power and are
confused. Or after all, the red on the cable looks like pin1.

Another thing they could think, is that if those are the power pins,
then they are the extra 4 pins. WRONG!
Those jumper pins are ABCD, and they are adjacent to pins 1-2.

Somebody may know he is holding the power, but think it is pin1,
because it is red.

 So somebody could easily make a bunch of mistakes, 1 mistake and get
it wrong. 2 mistakes and get it right. 3 mistakes and get it wrong.

It's a good idea to break a toothpick into pin20.
See that pin-out.

You could get that wrong too.. Which end was pin1, which side am I
looking at, which side was I looking at.  But once you have it done
for one cable, you can check new cables against that one!!!!!!

You a cheap drive first so you know you get it right.

And when you put the toothpick in, don't get frustrated and get a bit
of toothpick stuck under your finger nail!!!!!

Lots and lots of good techies have plugged it in the wrong way.even
when they know what they are doing. A minor lapse of concentration can
cause a mistake like that.   I would use a toothpick to block pin-20,
that's safer long term.

Laptop HDDs have pin20 missing.  .   And if you blocked that pin-20
hold in your 2.5" Connector, then you You can't plug it in the wrong
way even if you wanted to

Most 2.5" adaptor cables do not have that hold blocked.. Maybe most
PCB adaptors don't either. So make that amendment to htem.

So yeah. other than that, they are perfectly fine!! So, with those
precautions, they are fine.

They are extremely useful.

Re: Is it possible to connect a 2.5 inch drive to 3.5 in IDE cable?

On 8 Jun, 15:22, ""
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I mean hole not hold..


another mistake people might make.. That affects buying
them,reseraching them. Thinking about them.   Is not being crystal
clear that the motherboard and hdd connectors are male

The motherboard connectors have this encasing around them, which makes
them socket like. But they are male, they have pins in them. Just like
the IDE connector on a hard drive.

The IDE Cable is female both ends. Or rather..
Has any connectors, female.

A regular IDE cable has 3 connectors. One going to the MBRD.
A 2.5-3.5 IDE adaptor cable, has 2 connectors.

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