disadvantage of hd-suspension?

Silencing hard drives, optical drives and other storage devices

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axhind
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disadvantage of hd-suspension?

Post by axhind » Tue Feb 24, 2004 5:08 am

Hey all,

I spent some time browsing the forum, and read a lot of topics about silencing comps, including the ones where one gets advice about suspending his hd's. I have one remark concerning this method, but i'm not 100% sure if my thoughts on this matter are correct.
What about static electricity and the likes? I mean, if you suspend your hd's without them making any contact with your case, the hd is not grounded. And imho a computerpart that's not grounded is not a safe computerpart.

Am I making sense here or not? :wink:

ruprag
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Post by ruprag » Tue Feb 24, 2004 5:23 am

If you are worried about grounding your HDD then you can easily add grounding by just connecting a wire to the side of the HDD and then to the chassis of the computer.

aphonos
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Post by aphonos » Tue Feb 24, 2004 5:44 am

As has been said in other places in better ways and by people smarter than I: 2 ground wires in the PSU connector. 40 ground wires in an 80 wire IDE cable. Someone who knows more needs to weigh in on SATA connectors.

But in the worst case scenario, as ruprag said run your own ground wire between the drive and chassis.

m0002a
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Post by m0002a » Tue Feb 24, 2004 7:40 am

Since companies like Dell grommet mount their hard drives, I think you can be assured that it is safe. Dell actually has degreed engineers on their staff. Their liability would be enormous if any potential problem existed. However, I am not sure about grounding of the PSU.

However, I do cringe sometimes when I see people using certain kinds of foam, cardboard, etc, on the inside of their computer that are not fire rated, or not designed to be used around electrical circuits. I am certainly not saying that all foam is dangerous, but some foam may be. Remember that Rhode Island nightclub that went up in flames a few years ago when the acoustical foam behind the band caught fire?

aphonos
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Post by aphonos » Tue Feb 24, 2004 9:13 am

m0002a wrote:Remember that Rhode Island nightclub that went up in flames a few years ago when the acoustical foam behind the band caught fire?
Very few computers have pyrotechnic effects going off inside the case (especially those designed for silence) :wink: as was the case at the nightclub. Though perhaps there is a market for that kind of thing among modders???

Completely OT. Sorry. :( Now back to questions about disk suspension. :)

Good point about Dell and liability.

m0002a
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Post by m0002a » Tue Feb 24, 2004 10:34 am

First, I don't think it is off topic, since the materials in question are used to suspend hard drives.

Second, the pyrotechnics in the nightclub were sparks that ignited the foam. Electrical components can produce sparks. I have seen such sparks myself while installing a floppy drive (already wired) to the drive cage of a powered computer.

I am not saying that it is likely this will happen, but I would venture an educated guess that no PC manufacturer would be allowed by the regulatory agencies to use some of the materials described in this forum inside a computer. I am not speaking about all foam; but some foams, cardboard, etc, are not designed to be used around electrical circuits.

Baker
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Post by Baker » Tue Feb 24, 2004 11:20 am

That's interesting... has anyone taken a lighter to melamine yet?

If not... I'm gonna do it :lol:

lenny
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Post by lenny » Tue Feb 24, 2004 11:43 am

Baker wrote:That's interesting... has anyone taken a lighter to melamine yet?

If not... I'm gonna do it :lol:
Please do - and send photos if it's spectacular :-) Though I doubt it, since it's rated for use in the ceiling. If it's flammable, can you imagine the lawsuit, settlement and boat loads of happy lawyers?

IsaacKuo
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Post by IsaacKuo » Tue Feb 24, 2004 12:16 pm

I'm sure there are types of foam which may catch fire from sparks, but cardboard?

Have you ever played with fireworks on New Years or the 4th of July? A lot of those things are made of the cheapest grade cardboard imaginable, but disappointingly it is nigh IMPOSSIBLE to get spark shooting fireworks to ignite any of them!

My Calvin-like childhood fantasies of setting up spectacular battles with cardboard fireworks tanks and ships were dashed by the difficulty of setting even cheap cardboard on fire.

Of course, cardboard is used ubiquitously in fireworks, including mortar barrels. The stuff gets singed by burning gunpowder, but I suppose gunpowder sparks just don't get hot enough long enough to set cardboard on fire Heck, cardboard used to be a common material for 12 guage shotgun shells.

So, what about the heat/sparks that might be generated by a noteworthy computer hardware incident? Could it be enough to set cardboard on fire? I can't imagine 12v or 5v loose connection sparks could do it.

With these voltages, the only way I can think enough heat could be generated would be if there were some sort of circuit through some sort of heating element. Cardboard itself is not nearly conductive enough to short circuit anything. Maybe some sort of foam is a risk--foam which is conductive enough to cause a short circuit and resistive enough to heat up to ignition temperature. But not cardboard alone. I just can't see it.

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Post by IsaacKuo » Tue Feb 24, 2004 12:22 pm

Bringing those thoughts back on topic--for a hard drive suspension, I would indeed be wary of foam causing a short circuit. For my suspensions, I make sure nothing can accidentally contact the circuit board side of the hard drive. Since my suspensions support from below, this means the circuit board is on top--the hard drive is "upside-down" from the more common orientation.

I wouldn't feel any danger from directly placing the circuit board side against cardboard, but cardboard wouldn't be used anyway since it's not suitable for vibration dampening.

lenny
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Post by lenny » Tue Feb 24, 2004 12:26 pm

while on the subject of disadvantages, I think they are mainly (depending on suspension technique and suspended drive position) :

- out of path of airflow
- lost whatever cooling may be provided by attaching to case
- not secured - possible damage when moved

Trip
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Post by Trip » Tue Feb 24, 2004 12:41 pm

axhind, one possible problem with suspensions is that the drive won't be perfectly horizontal or vertical. Another is the obvious problem that some aren't made to transport and will allow the drive to swing in or even fly out the suspension and hit something. Suspensions have been made though w/o these problems.

As for flammability, Melamine is neither inflammable nor flammable.

Melamine "meets ASTM E-84 for flame and smoke," heh, and in reference to the burning club:

"A polyurethane panel typically costs about $150 while a melamine panel, which experts say withstands heat and is tested for fire resistance, sells for nearly $250."

As for Sorbothane... I think it IS somewhat flammable and the temperature range of the stuff I bought is only -20° to +180° F (mcmaster-carr.com)
Last edited by Trip on Tue Feb 24, 2004 12:45 pm, edited 1 time in total.

MikeC
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Post by MikeC » Tue Feb 24, 2004 12:45 pm

OK, firmly on topic... ;)

Assuming you suspend the right way -- ie, in airflow path, secure enough for light transport -- then the only disadvantage is that it is not enclosed, so that noise that gets radiated directly from the drive to the air is not as blocked as in an enclosed system -- like SmartDrive. AFAI am concerned, that is the ONLY real drawback, and it is a concern only if you have a pretty noisy or whiny drive to begin with... which if you value silence, you wouldn't do anyway. ;)

Xspringe
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Post by Xspringe » Tue Feb 24, 2004 1:03 pm

lenny wrote:while on the subject of disadvantages, I think they are mainly (depending on suspension technique and suspended drive position) :

- out of path of airflow
- lost whatever cooling may be provided by attaching to case
- not secured - possible damage when moved
The not secured issue can easily be resolved with some tape/velcro/other adhesive

DanceMan
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Post by DanceMan » Tue Feb 24, 2004 1:20 pm

Xspringe wrote:
lenny wrote: - not secured - possible damage when moved
The not secured issue can easily be resolved with some tape/velcro/other adhesive
How loose are you mounting them. My stretchy cord hangs could be picked up and moved in any position without any danger of falling out. I seriously doubt they are so tight as to be transmitting vibration.

DanceMan
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Post by DanceMan » Tue Feb 24, 2004 1:27 pm

IsaacKuo wrote:I'm sure there are types of foam which may catch fire from sparks, but cardboard?

Have you ever played with fireworks on New Years or the 4th of July? A lot of those things are made of the cheapest grade cardboard imaginable, but disappointingly it is nigh IMPOSSIBLE to get spark shooting fireworks to ignite any of them!
Has it never occurred to you that fireworks cardboard has been impregnated with fire retardent, for blatently obvious reasons?
Almost nothing burns hotter and faster, once started, than corrugated cardboard -- all the air channels.

IsaacKuo
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Post by IsaacKuo » Tue Feb 24, 2004 2:39 pm

The cheap chinese fireworks impregnated with fire retardant? Why? It would not, under any plausible circumstances, prevent a fire. Anything which might have ignited the cardboard would have ignited the fireworks fuses regardless.

No, there's no point in putting fire retardant into cheap fireworks, and it would merely increase manufacturing costs. Besides, these are really low margin dirt cheap products, so I'd think the cost savings would far outweigh any marginal benefit.

Trip
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Post by Trip » Tue Feb 24, 2004 2:39 pm

DanceMan wrote:
Xspringe wrote:
lenny wrote: - not secured - possible damage when moved
The not secured issue can easily be resolved with some tape/velcro/other adhesive
How loose are you mounting them. My stretchy cord hangs could be picked up and moved in any position without any danger of falling out. I seriously doubt they are so tight as to be transmitting vibration.
Add a set of bands around the other two sides of the HDD if needed - I couldn't find it but a guy used a wooden cradle with two bands guarding each side of the HDD. He gave credit to Mike C for the original idea but did it on another site.

aphonos
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Post by aphonos » Tue Feb 24, 2004 2:44 pm

Trip wrote:Add a set of bands around the other two sides of the HDD if needed - I couldn't find it but a guy used a wooden cradle with two bands guarding each side of the HDD. He gave credit to Mike C for the original idea but did it on another site.
Trip, correct me if this is not the idea to which you refer....

cmcquistion is the SPCR forum member and here is the link to his article at Overclockers Forums.

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Post by Trip » Tue Feb 24, 2004 2:53 pm

Scott, you're the man

axhind
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Post by axhind » Tue Feb 24, 2004 10:52 pm

m0002a wrote:Since companies like Dell grommet mount their hard drives, I think you can be assured that it is safe. Dell actually has degreed engineers on their staff. Their liability would be enormous if any potential problem existed. However, I am not sure about grounding of the PSU.
My harddrives in my Sonata are grommeted too, but that way they still make contact with the (grounded) chassis via the screws since they are pushed through the grommets into the harddrive.

And you can indeed ground your suspended harddrives by connecting them to the chassis with a wire, but the reason I thought of this issue is the fact that on most pictures I have seen on this forum the suspended harddisks are not grounded with such a wire.

Anyway, thanks for all your thoughts on this subject :) . And since none of you harddisk-suspenders has written about a dead harddrive because of the reason I mentioned, I suspect this to be a fairly safe method. Probably because of the fact that a harddisk is also grounded by its power- and datacable.

Oh, and thanks alot for introducing me to the magic world of firework-mechanics guys :D.

IsaacKuo
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Post by IsaacKuo » Wed Feb 25, 2004 7:22 am

If the screws are contacting the chassis, then the grommets aren't serving any purpose--worse, they might actually cause damage with "banging" forces.

At best, the screws are merely transmitting the vibrations of the hard drive directly to the case (the same as a traditional mount).

At worst, the screws are causing "banging" shock forces. Think of it as a vibrating object being bolted to a rigid plate--but the bolt is not completely tightened. The object has some ability to freely move a small amount, but when the bolt hits the plate it will be with a hammer-like "bang".

The proper way for grommets to isolate vibrations is for the screws and hard drive to ONLY contact the grommets.

m0002a
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Post by m0002a » Wed Feb 25, 2004 7:31 am

Axhind, I also have a Sonata, and usless you are doing something unusual, the hard drive screws do not touch the chasis. As noted by others, both the power and data cables for the drive have ground wires.

I did have a problem with a Pentium 90 years ago in that the floppy drive would not work properly unless it was grounded to the chasis. I don't know if the same problem existed for older hard drives.

axhind
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Post by axhind » Thu Feb 26, 2004 12:55 am

m0002a wrote:Axhind, I also have a Sonata, and usless you are doing something unusual, the hard drive screws do not touch the chasis. As noted by others, both the power and data cables for the drive have ground wires.

I did have a problem with a Pentium 90 years ago in that the floppy drive would not work properly unless it was grounded to the chasis. I don't know if the same problem existed for older hard drives.
ok now you guys got me confused :oops: . maybe I didn't explain it right because English is not my language. Second try: When you don't use the grommets, you put a screw in the hole of the harddrive cage from below, then you put the hd in the cage and you screw it in the harddrive, right?

visual attempt:
==== HD
---||----cage
screw

now, when you use a grommet, you just put it between the hd and the cage, and since its a "double" grommet it's between the cage and the top of the screw too.

visual:
===== HD
---||-grommet around screw
---||--cage
---||-grommet around screw

...

LOL, ok now I see what you guys mean and that you are actually right and I'm wrong :D Oh my god, I so ashamed :oops: Ah well, never to old to learn he :)

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Post by dukla2000 » Thu Feb 26, 2004 1:58 am

aphonos wrote:As has been said in other places in better ways and by people smarter than I: 2 ground wires in the PSU connector. 40 ground wires in an 80 wire IDE cable. Someone who knows more needs to weigh in on SATA connectors.
My SATA power connector takes 2 ground cables from the psu and spreads them across a couple of pins. The SATA data cable has only 3 grounds (pins 1, 4 & 7). And to be completely anal the 40 pin IDE connector has 7 ground pins and the UltraDMA spec only added the 40 grounds to the cable (to reduce crosstalk), not the pinouts.

And of course the other side of this equation: of all the hdd, fdd & optical disks I have checked, there is no resistance between the signal ground, power ground and chassis of the things. Folklore says some very old MFM or wotever hdd were not: if this were true and I managed to destoy it by NOT grounding the chassis I reckon I would actually be pleased :twisted:

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