SSD and computer casing.

My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.

On Sun, 15 Apr 2018 09:51:56 +1000, Peter Jason wrote:

My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.

It shouldn't be a problem if the SSD has a case around it. I wouldn't
let a MSATA type drive flop around in there.

Speaking of flopping, I'm using an old Lenovo M72 It has room for one
3.5" drive and I've one 2.5" SSD and one 2.5" disk drive. There
wasn't enough room in there to mount the SSD to the bracket and still
get the connectors to mate properly, so it is loose and works fine (my
desktop doesn't get moved often or treated harshly). I've also
plugged in plenty of drives that weren't screwed down to see what was
on them without the cases being grounded.

Plenty of laptops work without any earth ground on the power supply,
but with an internal supply, a grounded case will protect you from a
shock if water gets in it or a wire shorts to the case.

On Sun, 15 Apr 2018 09:51:56 +1000, Peter Jason wrote:

My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.

If you have the space to install a 3.5" storage device then you might
consider a conversion tray which provides for you to securely install
a 2.5" drive to a 3.5" bay. Check your local PC parts store.

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.

I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the ohmmeter,
between GND and chassis, and you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul

On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.

I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the ohmmeter,
between GND and chassis, and you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the ohmmeter,
between GND and chassis, and you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/

Paul

On Sun, 15 Apr 2018 09:51:56 +1000, Peter Jason wrote:

My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs


Go to Amazon.com and buy an SSD tray or mounting bracket for each SSD
you have. They are only a few dollars each and will let you install
the SSDs in 3.5" drive bays.

On Sun, 15 Apr 2018 09:25:01 -0600, ken1943
wrote:


Go to Amazon.com and buy an SSD tray or mounting bracket for each SSD
you have. They are only a few dollars each and will let you install
the SSDs in 3.5" drive bays.

I wrapped one in bubble wrap and stuck in a 3.5 bay.



Do they get hot? I don't know for sure, but if they do, what you did
could start a fire.

"Paul" wrote in message news

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the
ohmmeter,
between GND and chassis, and
you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/

Paul

Paul,

Have no idea why you would expect the SSD to be isolated from case ground.
Everything in the computer and the case itself is tied to the grid ground.
Mount a motherboard and the mounting screws screw into the case as well as
the screw heads tighten down on ground pads on the motherboard. SSD's are
also grounded when placed in a mounting tray to case ground.

As for the longer pins on power and data connectors, the pins that are
designated as ground pins are longer to insure a ground connection is made
before any data pins mate to prevent static discharges. This pin design
also accommodates "hot swap" capable devices such as hard drives and SSD's.

While it's always good practice to use measures to prevent ESD when mounting
a device such as a SSD, do not isolate it from the mounting mechanisms such
as placing an insulator between it and a metal case. Depending on the SSD
(some cases are plastic), the metal case is the heat sink as shown in the
link you included in your post. Please note that the logic board is held
in-place by a screw in the back that fastens to the SSD case and tightens
against a ground pad on the SSD logic board.
--


Bob S.

On 15/04/2018 00:51, Peter Jason wrote:
the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs

Why buy a 2.5 inch drives when you don't have the facility to use them?
Do I sense some mental problems here? Why not plan in advance when
buying something!!. There is no point in buying something just because
it is new and your neighbour has got one. It's plain silly.

3.5 inch drives are much cheaper because they are produced in bulk and
the users change their drives more frequently than on their laptops.
2.5 were made mainly for laptops but these days desktops and laptops are
almost identical but desktops still have more accommodation for
different devices.


/--- This email has been checked for viruses by
Windows Defender software.
//https://www.microsoft.com/en-gb/windows/comprehensive-security/


--
With over 600 million devices now running Windows 10, customer
satisfaction is higher than any previous version of windows.

On 4/15/2018 11:52 AM, Bob_S wrote:
"Paul"Â* wrote in message news

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium.Â* Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface.Â*Â* Is this a problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

Â*Â*Â* GNDÂ*Â*Â*Â*Â*Â*Â*Â* GNDÂ*Â*Â*Â*Â*Â*Â*Â* GNDÂ*Â*Â* === logic ground pins are longer
Â*Â*Â*Â*Â*Â*Â* tx+ tx-Â*Â*Â*Â* rx+ rx-Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* on the SSD connector. The data
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* pins on the 7 pin data are
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* recessed. Check with the
ohmmeter,
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* between GND and chassis, and
you'll
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
Â*Â* what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Â*Â* Just like you would not touch any "hot" Molex pins,
Â*Â* to the computer case metal posts. The motherboard has a hard
Â*Â* short to the chassis, through the standoffs. Most everything
Â*Â* in the computer, has a hard ground. The only poorly designed
Â*Â* feature, is "plastic fascia" on the front of the computer,
Â*Â* around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
Â*Â* SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
Â*Â* scuff across the carpet if you must, pick up the
Â*Â* SSD by the ESD bag, touch the ESD bag plastic on
Â*Â* the inside of the bag, to bring yourself and the bag contents
Â*Â* to the same potential. With your other hand, touch
Â*Â* the computer chassis. Now, everything is "drained" to
Â*Â* the same electrostatic potential, you can remove the
Â*Â* SSD from the ESD bag, and connect it to SATA power
Â*Â* and SATA data.

Â*Â* By using the series resistance of the ESD bag, to limit
Â*Â* ESD current flow, you're *safely* bringing the SSD up
Â*Â* to the same electrostatic potential as the thing you
Â*Â* wish to connect it to.

Note: I just changed my handling procedure! as a result
Â*Â*Â*Â*Â* of this ohmmeter measurement. I'd assumed SSD chassis
Â*Â*Â*Â*Â* were drain connected, not "hard" connected. Now I
Â*Â*Â*Â*Â* will have to start using ESD bags for them, just as
Â*Â*Â*Â*Â* I do for hard drives.

Â*Â* Paul


Thanks Paul.Â* I have put my SSDs in plastic sleeves, and rested this
combination on cardboard.Â*Â* I thought this might be the cause of my
computer restarts.Â*Â* Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/


Â*Â* Paul

Paul,

Have no idea why you would expect the SSD to be isolated from case
ground. Everything in the computer and the case itself is tied to the
grid ground. Mount a motherboard and the mounting screws screw into the
case as well as the screw heads tighten down on ground pads on the
motherboard.Â* SSD's are also grounded when placed in a mounting tray to
case ground.

As for the longer pins on power and data connectors, the pins that are
designated as ground pins are longer to insure a ground connection is
made before any data pins mate to prevent static discharges.Â* This pin
design also accommodates "hot swap" capable devices such as hard drives
and SSD's.

While it's always good practice to use measures to prevent ESD when
mounting a device such as a SSD, do not isolate it from the mounting
mechanisms such as placing an insulator between it and a metal case.
Depending on the SSD (some cases are plastic), the metal case is the
heat sink as shown in the link you included in your post.Â* Please note
that the logic board is held in-place by a screw in the back that
fastens to the SSD case and tightens against a ground pad on the SSD
logic board.

Had no idea the ground pins were longer, thanks Data, er, Paul.

Mike S wrote:
On 4/15/2018 11:52 AM, Bob_S wrote:
"Paul" wrote in message news

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for
2.5"
SSDs I have them resting on an aluminium surface. Is this a
problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the
ohmmeter,
between GND and chassis,
and you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/


Paul

Paul,

Have no idea why you would expect the SSD to be isolated from case
ground. Everything in the computer and the case itself is tied to the
grid ground. Mount a motherboard and the mounting screws screw into
the case as well as the screw heads tighten down on ground pads on the
motherboard. SSD's are also grounded when placed in a mounting tray
to case ground.

As for the longer pins on power and data connectors, the pins that are
designated as ground pins are longer to insure a ground connection is
made before any data pins mate to prevent static discharges. This pin
design also accommodates "hot swap" capable devices such as hard
drives and SSD's.

While it's always good practice to use measures to prevent ESD when
mounting a device such as a SSD, do not isolate it from the mounting
mechanisms such as placing an insulator between it and a metal case.
Depending on the SSD (some cases are plastic), the metal case is the
heat sink as shown in the link you included in your post. Please note
that the logic board is held in-place by a screw in the back that
fastens to the SSD case and tightens against a ground pad on the SSD
logic board.

Had no idea the ground pins were longer, thanks Data, er, Paul.

Advanced ground prevents ESD or DC potential problems on
tx+,tx-,rx+,rx- .

Some connector systems use three lengths of pins, or even resort
to power bugs, to sequence which pins touch first, second, third
on an interface. They've done some complicated ones.

Paul

Bob_S wrote:
"Paul" wrote in message news

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for 2.5"
SSDs I have them resting on an aluminium surface. Is this a problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the
ohmmeter,
between GND and chassis, and
you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/


Paul

Paul,

Have no idea why you would expect the SSD to be isolated from case
ground. Everything in the computer and the case itself is tied to the
grid ground. Mount a motherboard and the mounting screws screw into the
case as well as the screw heads tighten down on ground pads on the
motherboard. SSD's are also grounded when placed in a mounting tray to
case ground.

As for the longer pins on power and data connectors, the pins that are
designated as ground pins are longer to insure a ground connection is
made before any data pins mate to prevent static discharges. This pin
design also accommodates "hot swap" capable devices such as hard drives
and SSD's.

While it's always good practice to use measures to prevent ESD when
mounting a device such as a SSD, do not isolate it from the mounting
mechanisms such as placing an insulator between it and a metal case.
Depending on the SSD (some cases are plastic), the metal case is the
heat sink as shown in the link you included in your post. Please note
that the logic board is held in-place by a screw in the back that
fastens to the SSD case and tightens against a ground pad on the SSD
logic board.

There are two ground philosophies for protecting assemblies
from ESD.

Neither was followed in this case.

Paul

ken1943 wrote:
On Sun, 15 Apr 2018 08:32:03 -0700, Ken Blake
wrote:

On Sun, 15 Apr 2018 09:25:01 -0600, ken1943
wrote:

Go to Amazon.com and buy an SSD tray or mounting bracket for each SSD
you have. They are only a few dollars each and will let you install
the SSDs in 3.5" drive bays.
I wrapped one in bubble wrap and stuck in a 3.5 bay.


Do they get hot? I don't know for sure, but if they do, what you did
could start a fire.

They run cool. Check specs. on one, they only draw under 2-4 watts for
the size I use. Probably depends on how many chips/capacity one has.

For the record, what's been "printed on the tin" of SSDs
is just plain wrong.

There is at least one web site, which has done measurements
on a variety of models, which gives more realistic numbers.
The site would open a box that said "200mW" on the outside,
and find a healthy 2-3W draw instead, during sustained write.

What's wrong with the "printed on the tin" value, is some
marketing bunny decided to print the "devsleep" or other
pointless numbers on the outside of the box. Like some
badge of honor. When in fact, we want the "continuous read"
or "continuous write" value, or high power state values,
to decide how to handle the devices in various situations.

The 2-4 watt value is a good estimate, first of all.

There are some Sandforce ones up around 7 watts. That power
number would not be sustained forever, but on a sustained
write, it might be. The power might be coming from the
data compression solution those controllers use. The ability
to attempt to compress a full-rate stream, is pretty
damn impressive. It's gotta use some power.

One reason for needing to know the SSD peak power, is when
the SSD is on a USB conversion cable (tether). This is why I measured
the power on my SSDs and they all seem to be compatible
with USB2 ports, if I use a converter. A USB2 port is good
for 2.5W long term, 5W short term, and so a 7W SSD being
"cloned over" on an SSD port, has the possibility of
opening the Polyfuse on the motherboard, in mid-transfer.

A second reason for needing a decent high-power-state value,
is for laptops. Where the laptop bay is an "insulating"
design, and from previous experience, only 5400 RPM drives
"survived" in the completely-uncooled bay. A Kingston
(Sandforce) drive might not be the best choice for
such an application.

Once an SSD is inside a desktop, there's no power engineering
to do in there. If you're not cloning on a tether, but
just cabling to the internal SATA cables, you'll be fine
no matter what it is. Leave one exposed surface, so
the small amount of heat can escape. Like, don't
build a styrofoam box for it.

There are some PCI Express ones that draw 15W. Again, not
an issue, as they're open on both sides. And if the
controller on those is a hot spot, it'll have a heatsink.

Paul

"Paul" wrote in message news

Bob_S wrote:
"Paul" wrote in message news

Peter Jason wrote:
On Sat, 14 Apr 2018 22:25:50 -0400, Paul
wrote:

Peter Jason wrote:
My computer case is of Aluminium and earthed to a domestic copper
water pipe. , the casing of the Samsungs SSDs seem to be anodized
aluminium. Since my computer case is old it has no provision for
2.5"
SSDs I have them resting on an aluminium surface. Is this a
problem?
I assume the SSDs have internal insulation.
I just measured a couple SSDs here, and son of a bitch,
there's a hard connection between SSD casing and logic ground!

That's not supposed to be good for ESD handling.

I was expecting to find a 1 megohm connection between
aluminum SSD casing and the logic ground on the SSD.

But it's a hard short.

*******

The chassis of your computer case, runs at logic ground
potential.

The casing of your SSD, runs at logic ground potential.

This means you can safely rest the SSD on the bottom of
the computer case, without any "thru" current flowing.

Just don't touch a 3.3V, 5V, or 12V pin from some
Molex connector, to the chassis of the SSD. Since
it's a hard ground, we can't be carelessly resting
a Molex power pin in contact (somehow) with the chassis.

While the pins on Molex are flush or
slightly recessed, there might be some conceivable
way for something to touch. And my finding a
hard ground on the SSD chassis, is not a good
thing.

I'll be extra careful in future, to keep Molex
away from it.

I was really expecting to find a 1Megohm (high resistance)
drain between shiny aluminum SSD casing and the logic
ground next to the data pins of the SSD.

GND GND GND === logic ground pins are longer
tx+ tx- rx+ rx- on the SSD connector. The data
pins on the 7 pin data are
recessed. Check with the
ohmmeter,
between GND and chassis, and
you'll
see the hard short I measured.

Summary:

1) Safe to rest SSD on bottom of computer case, no matter
what the casing is made of.

2) Don't touch any "hot" Molex pins, to the SSD housing.
Just like you would not touch any "hot" Molex pins,
to the computer case metal posts. The motherboard has a hard
short to the chassis, through the standoffs. Most everything
in the computer, has a hard ground. The only poorly designed
feature, is "plastic fascia" on the front of the computer,
around front USB ports, which is a poor way to handle ESD issues.

3) Don't scuff across the carpet and pick up your
SSD by the aluminum casing. Keep unused SSDs in an ESD bag,
scuff across the carpet if you must, pick up the
SSD by the ESD bag, touch the ESD bag plastic on
the inside of the bag, to bring yourself and the bag contents
to the same potential. With your other hand, touch
the computer chassis. Now, everything is "drained" to
the same electrostatic potential, you can remove the
SSD from the ESD bag, and connect it to SATA power
and SATA data.

By using the series resistance of the ESD bag, to limit
ESD current flow, you're *safely* bringing the SSD up
to the same electrostatic potential as the thing you
wish to connect it to.

Note: I just changed my handling procedure! as a result
of this ohmmeter measurement. I'd assumed SSD chassis
were drain connected, not "hard" connected. Now I
will have to start using ESD bags for them, just as
I do for hard drives.

Paul


Thanks Paul. I have put my SSDs in plastic sleeves, and rested this
combination on cardboard. I thought this might be the cause of my
computer restarts. Also I have disabled all "fast startups" via the
registry.

I wouldn't entirely insulate the thing. Some SSDs have
high peak power usage (SandForce compression), and they
get a little warm.

Put a cardboard underneath if you like. Leave
at least one metal surface for cooling.

In this review, you can see (and it's mentioned in the text),
that thermal pads were used on all the NAND chips. That means
both metal surfaces are used for their slight cooling advantage.

http://www.thessdreview.com/our-revi...-review-512gb/

Paul

Paul,

Have no idea why you would expect the SSD to be isolated from case
ground. Everything in the computer and the case itself is tied to the
grid ground. Mount a motherboard and the mounting screws screw into the
case as well as the screw heads tighten down on ground pads on the
motherboard. SSD's are also grounded when placed in a mounting tray to
case ground.

As for the longer pins on power and data connectors, the pins that are
designated as ground pins are longer to insure a ground connection is
made before any data pins mate to prevent static discharges. This pin
design also accommodates "hot swap" capable devices such as hard drives
and SSD's.

While it's always good practice to use measures to prevent ESD when
mounting a device such as a SSD, do not isolate it from the mounting
mechanisms such as placing an insulator between it and a metal case.
Depending on the SSD (some cases are plastic), the metal case is the heat
sink as shown in the link you included in your post. Please note that
the logic board is held in-place by a screw in the back that fastens to
the SSD case and tightens against a ground pad on the SSD logic board.

There are two ground philosophies for protecting assemblies
from ESD.

Neither was followed in this case.

Paul

Paul,

Not sure I follow your logic on this. The OP said he had his case grounded
to a copper pipe. What wasn't stated is how his power supply is grounded or
if it was even plugged in. In the US, the 3rd lug on a plug is the green
(safety) ground and in a typical home wiring setup, the white wire and green
are tied to a single bus bar in the distribution panel so as to prevent
ground loops / current loops.

So while his setup using a ground from the case to a copper water pipe could
potentially create a ground loop if there were other wiring problems, it
still is ground as long as there's no interruption to earth ground in that
copper pipe and in his wiring and would dissipate any ESD charge.

Potential for ESD would be from him picking up the SSD and then plugging it
in before he touched the case (grounding himself) and creating a arc between
his hand holding the SSD and getting the data or power connectors close
enough so the static potential went from him to the ground pins on the cable
or the case.

That’s' why the manufactures include warnings about using ground straps
and/or touching the case before working on it. What people don't realize is
that usually, they unplug the power cord from the wall or the power supply
and that’s when their case is no longer grounded. But in the OP's situation,
he had an additional ground to a water pipe. That may or may not be a good
situation depending on his house wiring and I've never seen a power supply
plug without a polarized plug. Now if the wall socket (old house wiring)
does not have a safety ground, then his water pipe ground is a good idea.

I've worked at radar sites and on some of the largest computer installations
in the world and worked worked with power engineers that specialize in how
"all things" need to be grounded and why. It is a complicated field of
study and ESD can create havoc on computer components when you have
thousands of volts jumping between you and the computer.

So I'm not trying to argue with you but saying "Neither was followed in this
case" didn't make sense to me. Perhaps you could expand on the "Neither" a
bit. I'm not sure if you are referring to the OP or to your own situation.
If it's your own, then I'll shut up and sit down cause I don't know what or
how you were doing your measurements.
--


Bob S.