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Re: Looking for an external enclosure for a salvaged 2.5 laptop drive.

 
 
Paul
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Posts: n/a
 
      1st Dec 2013
John wrote:
> To be used for backup images for both a new laptop and a work station.
> Both ESATA and USB3 capability would be great.
>
> I have a laptop with a bad LCD and am going to remove the drive anyway
> before the rest is recycled. So I thought I may as well put the drive to
> use. Its a 500GB 5400 RPM about 2-1/2 years old.
>
> Any recommendations?
>
> Thanks,
> John


To find good USB3 and ESATA, I had to look for a 3.5" enclosure.

http://www.newegg.com/Product/Produc...82E16817392050

ESATA comes a couple ways. The original ESATA was a data only cable.
It assumed the hard drive was self powered. Thus, the enclosure end
had its own power adapter.

Some of the ESATA enclosures may use a USB cable as a source of +5V.
But then, I don't know how the drive selects which I/O standard to use.
Or whether it's one of those power-only USB cables with a barrel power
connector on the end.

ESATA itself, had a couple contacts added to the ends of the connector.
The trouble with that concept, is on the computer end, you could either
send 5V down the cable, or 12V. The 12V option was good for 3.5" drives,
while 5V made sense for the 2.5" devices. This was effectively
turning users into engineers, selecting components to make the
setup work. And you can imagine, if a family member came along
and connected the wrong stuff, there would be issues. In the description
here, I can barely follow the power options. This is the so-called
eSATAp non-standard.

http://en.wikipedia.org/wiki/Esata#eSATAp

So plain ESATA on the enclosure is preferred. Plus having a power adapter
for the housing. That's how I ended up selecting the 3.5" enclosure,
something that at least has the right infrastructure, even if
the drive doesn't conveniently bolt into place.

*******

If you go for just USB as an interface standard, this is so much easier.
The 5V on USB bus, can power some (but not all) 2.5" drives. Some
drives draw a little too much current on +5V. What helps though, is
the USB3 standard allows a bit more current flow, which helps cover
more of the 2.5" hard drive market.

http://www.newegg.com/Product/Produc...82E16817392043

The 2.5" drives can draw anywhere from 500mA to 1 amp during spinup
phase. USB2 is 500mA, USB3, is 900mA. USB on desktops is policed by
a Polyfuse, which is set several times higher than the official
current flow limit (suggesting using the one cable, should
always have worked). On laptops, an 8 pin chip may be used, in
place of a self-recovering Polyfuse, and the current limit on
a laptop may be set different than a desktop. A laptop is more
likely to have issues powering the external drive.

Back when there was more trouble getting the 2.5" drives to spin
up on USB power, that lead to the invention of the USB "Y" cable.
The cable had two "computer" ends on it. One fork had data and power,
the other leg of the fork had just power pins. The idea was to
steal power from two USB ports. From a gambler's perspective,
there are better odds now, with modern gear, that this won't
be necessary. (Versions of this also exist, where the second
USB computer end, is on its own cable with a barrel power connector
as the output on the other end.)

http://www.amazon.com/Bytecc-USB2-HD.../dp/B002GWMLE8

On that Nexstar enclosure, there is a barrel power input on the
left hand side. This would allow usage of a USB2 to barrel power
cable, in situations where the drive was drawing 1 ampere at
startup. When paralleling power like that, the power source
ideally should come from the same source supply (like, both
traceable to the 5V on your desktop).

http://images17.newegg.com/is/image/newegg/17-392-043-Z04?$S640$

And this is the variation on the Y cable, for connecting a
USB port as a power source for the drive enclosure.

http://www.newegg.com/Product/Produc...9SIA30R14K5096

If you use a USB3 port between computer and
USB3 enclosure, you're not likely to need the barrel
thing. Still, if you run into problems, the presence of
the barrel connector means you may still be able to
salvage the value of the enclosure.

The algorithm would go like this. Try just a USB2 or USB3
cable, from enclosure to drive. If you can read the drive, you're
done. If you cannot read the drive, then it's time to explore
adding power via the barrel power input.

*******

A dock is another way to do this. You could buy a dock and
just leave the drive plugged into it. What happens with the 2.5" drives,
is there is a plastic insert that fills the space for the
naturally 3.5" dock, and that's how a 2.5" drive is adapted
to fit. This isn't the ideal configuration, but the
benefit of docks, is sometimes you get different I/O
options than you get on the enclosure concept.

http://www.newegg.com/Product/Produc...0VN-0003-000H5

*******

It all seems to give the impression sometimes, that
nobody really thought out external drives all that
carefully :-)

Paul
 
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Paul
Guest
Posts: n/a
 
      1st Dec 2013
John wrote:
> On 12/1/2013 8:38 AM, Paul wrote:
>> John wrote:
>>> To be used for backup images for both a new laptop and a work station.
>>> Both ESATA and USB3 capability would be great.
>>>
>>> I have a laptop with a bad LCD and am going to remove the drive anyway
>>> before the rest is recycled. So I thought I may as well put the drive
>>> to use. Its a 500GB 5400 RPM about 2-1/2 years old.
>>>
>>> Any recommendations?
>>>
>>> Thanks,
>>> John

>>
>> To find good USB3 and ESATA, I had to look for a 3.5" enclosure.
>>
>> http://www.newegg.com/Product/Produc...82E16817392050
>>
>> ESATA comes a couple ways. The original ESATA was a data only cable.
>> It assumed the hard drive was self powered. Thus, the enclosure end
>> had its own power adapter.
>>
>> Some of the ESATA enclosures may use a USB cable as a source of +5V.
>> But then, I don't know how the drive selects which I/O standard to use.
>> Or whether it's one of those power-only USB cables with a barrel power
>> connector on the end.
>>
>> ESATA itself, had a couple contacts added to the ends of the connector.
>> The trouble with that concept, is on the computer end, you could either
>> send 5V down the cable, or 12V. The 12V option was good for 3.5" drives,
>> while 5V made sense for the 2.5" devices. This was effectively
>> turning users into engineers, selecting components to make the
>> setup work. And you can imagine, if a family member came along
>> and connected the wrong stuff, there would be issues. In the description
>> here, I can barely follow the power options. This is the so-called
>> eSATAp non-standard.
>>
>> http://en.wikipedia.org/wiki/Esata#eSATAp
>>
>> So plain ESATA on the enclosure is preferred. Plus having a power adapter
>> for the housing. That's how I ended up selecting the 3.5" enclosure,
>> something that at least has the right infrastructure, even if
>> the drive doesn't conveniently bolt into place.
>>
>> *******
>>
>> If you go for just USB as an interface standard, this is so much easier.
>> The 5V on USB bus, can power some (but not all) 2.5" drives. Some
>> drives draw a little too much current on +5V. What helps though, is
>> the USB3 standard allows a bit more current flow, which helps cover
>> more of the 2.5" hard drive market.
>>
>> http://www.newegg.com/Product/Produc...82E16817392043
>>
>> The 2.5" drives can draw anywhere from 500mA to 1 amp during spinup
>> phase. USB2 is 500mA, USB3, is 900mA. USB on desktops is policed by
>> a Polyfuse, which is set several times higher than the official
>> current flow limit (suggesting using the one cable, should
>> always have worked). On laptops, an 8 pin chip may be used, in
>> place of a self-recovering Polyfuse, and the current limit on
>> a laptop may be set different than a desktop. A laptop is more
>> likely to have issues powering the external drive.
>>
>> Back when there was more trouble getting the 2.5" drives to spin
>> up on USB power, that lead to the invention of the USB "Y" cable.
>> The cable had two "computer" ends on it. One fork had data and power,
>> the other leg of the fork had just power pins. The idea was to
>> steal power from two USB ports. From a gambler's perspective,
>> there are better odds now, with modern gear, that this won't
>> be necessary. (Versions of this also exist, where the second
>> USB computer end, is on its own cable with a barrel power connector
>> as the output on the other end.)
>>
>> http://www.amazon.com/Bytecc-USB2-HD.../dp/B002GWMLE8
>>
>>
>>
>> On that Nexstar enclosure, there is a barrel power input on the
>> left hand side. This would allow usage of a USB2 to barrel power
>> cable, in situations where the drive was drawing 1 ampere at
>> startup. When paralleling power like that, the power source
>> ideally should come from the same source supply (like, both
>> traceable to the 5V on your desktop).
>>
>> http://images17.newegg.com/is/image/newegg/17-392-043-Z04?$S640$
>>
>> And this is the variation on the Y cable, for connecting a
>> USB port as a power source for the drive enclosure.
>>
>> http://www.newegg.com/Product/Produc...9SIA30R14K5096
>>
>> If you use a USB3 port between computer and
>> USB3 enclosure, you're not likely to need the barrel
>> thing. Still, if you run into problems, the presence of
>> the barrel connector means you may still be able to
>> salvage the value of the enclosure.
>>
>> The algorithm would go like this. Try just a USB2 or USB3
>> cable, from enclosure to drive. If you can read the drive, you're
>> done. If you cannot read the drive, then it's time to explore
>> adding power via the barrel power input.
>>
>> *******
>>
>> A dock is another way to do this. You could buy a dock and
>> just leave the drive plugged into it. What happens with the 2.5" drives,
>> is there is a plastic insert that fills the space for the
>> naturally 3.5" dock, and that's how a 2.5" drive is adapted
>> to fit. This isn't the ideal configuration, but the
>> benefit of docks, is sometimes you get different I/O
>> options than you get on the enclosure concept.
>>
>> http://www.newegg.com/Product/Produc...0VN-0003-000H5
>>
>> *******
>>
>> It all seems to give the impression sometimes, that
>> nobody really thought out external drives all that
>> carefully :-)
>>
>> Paul

>
>
>
> Thank you for the thorough explanation.
>
> Basically you recommend a separate power supply as used in a docking
> scheme?
> If so that makes more sense than drawing power from a USB port, it has
> enough to do already.
>
> * The first one above is $50, comes with both an ESATA and USB3 cable
> but appears to be 3.5" drive only.
>
> The 2nd is inexpensive ($16) but USB only & no separate power supply.
>
> Skipped the 'Y' cable thing as both USB ports are side by side on the
> work station and are connected to the same block. Who knows on the
> laptop, won't be delivered until next week, but I would suspect a
> similar hookup internally, after all it only makes sense.
>
> The last is a possibility if all else fails and certainly reasonably
> priced.
>
> * Do they sell adapters to go from 3.5 to 2.5? I like the first one you
> pointed out but don't have a spare 3.5" drive.
>
> Also is there an easy way to tell which ports are USB2 and which are USB3?
>
>
> John


If the drive is 500GB, chances are it is SATA. 2.5" SATA and 3.5" SATA
use the same physical interface dimensions. A 2.5" drive would fit
a 3.5" SATA enclosure connector. When drives get to 1.8", they
switch to microSATA and an adapter is required.

If the drive is IDE, the 2.5" laptop drives use a 44 pin
connector, with 2mm spacing. The 3.5" desktop drives, use
a 40 pin connector, with 0.1 inch spacing. An adapter is
needed to go between those two standards. It's a good question,
whether a 3.5" IDE enclosure would have space for a 2.5" IDE 44 pin,
plus an adapter.

(IDE adapter, 2.5" IDE drive to 3.5" IDE desktop cabling)
http://www.newegg.com/Product/Produc...82E16812196219

My assumption is, your hard drive is SATA. And really the only
issue at that point, is fastening the 2.5" drive in position,
in the 3.5" sled. You can buy 2.5" to 3.5" mechanical adapters,
which would be one solution for SATA.

If the drive was IDE, I would just buy a matching enclosure
(2.5" enclosure for 44 pin IDE, 3.5" or 5.25" enclosure for
40 pin IDE drive).

*******

USB3 ports are powder blue in color. A USB3 port has a total
of nine contacts. Five contacts for USB3 (TX+/- diff pair,
RX+/- diff pair, ground). Four contacts for USB2 (VCC, D+, D-, GND).
If you plug a USB3 device into a USB2 hole, only the four
contact portion makes contact. The five contact section is
recessed in the connector. When shopping for my first
and only USB3 flash drive, the plastic packaging prevented
me from visually inspecting the connector. So I couldn't
verify it really was a USB3 device, until I got it home
and under a strong light source.

*******

With regard to power sources, it's really hard to offer
advice that is rock solid in every case. I know with the
enclosure I have here, definitely and for certain,
the power section is independent of the interface, and
so I know any combination of wiring is OK. I can connect
just the USB portion and leave the power supply disconnected.
I can connect the power supply to the enclosure, and leave
the USB disconnected. Again, no problem.

A problem that arises occasionally with USB devices, is
the manufacturer connects an external power source, in
common with the VCC pin on the USB bus cable. This can cause
a lot of current to flow backwards in the cable.

In the case of a 3.5" external enclosure, we can be
fairly certain the designers do not connect
+5V or +12V of the enclosure power, to the VCC pin on
the USB side. But, when it comes to 2.5" enclosures,
there is a good chance they'll do something stupid,
like connect the barrel connector to the VCC pin.
What we interpret this to mean, is the barrel connector
in that case, is only meant for a USB to barrel power source.
(Since in that case, the USB power comes from the ATX supply,
and it's the same source as the primary USB interface.)
You should not connect an external power adapter +5V to
the barrel connector on the enclosure in that case. You'd
need an ohmmeter to verify the connection is present.

The first time I saw a proper implementation, it was a
datasheet for a hub chip. The manufacturer showed how to
build a powered hub. The hub was intended to support
both externally powered, and USB bus powered operation.
They solved the problem with power, by using a small
relay. When the external power adapter is plugged in,
the presence of power energizes the small relay. The
relay contacts break the connection between USB bus power
and enclosure power. In that way, there is no danger the
external adapter will drive current backwards into the
ATX supply. (That's really only an issue if it causes the
Polyfuse to trip, and the USB port state changes to
disabled due to the port power failure being detected.)

Your average $15 USB2 enclosure, if it has a barrel connector,
chances are it's connected to bus power. They could not
afford to stick a relay in there, for a $15 product. But
if you bought one of those powered hubs I described, then
those are intended for powering with an external adapter.

So this is a safe configuration. Both power sources come
from the same original source. No loop current flows.

USB_cable ---------- barrel_power
USB enclosure with
USB_cable ---------- power+data barrel power provision

If we do it this way

Ext. +5V ---------- barrel_power
USB enclosure with
USB_cable ---------- power+data barrel power provision

then power can flow from left to right on the top cable, and
from right to left on the bottom cable.

A USB hub, with the relay present, looks like this.
Here, Ext. adapter power can't flow up the USB cable, because
the power path has the relay contacts there to stop it from
flowing. The relay opens, any time power appears
on the barrel_power input.

Ext. +5V ---------- barrel_power
USB powered hub
---------- data
USB_cable
---/ ----- power (Power can be interrupted by relay)

So the Y cable concept, or the USB to barrel concept
is pretty safe. If you use an wall powered +5V source to
plug into the barrel connector, then you'd need to ask
more questions. Maybe, even check to see if a small
plastic relay is present as a form of protection.

HTH,
Paul

 
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