Can I place prottype board (power on) on top of silver anti-static bag and work?.

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G

GS

I don't have anti static mat in my cube, if I place prottype board
(by power on) on top of silver anti-static bag and keep working with
that prototype board?. I turned power on, Is it Ok if I keep powered
board on top of anti-static bag, sometimes night times I used to leave
that board on, will be Ok?. Thanks.
 
GS said:
I don't have anti static mat in my cube, if I place prottype board
(by power on) on top of silver anti-static bag and keep working with
that prototype board?. I turned power on, Is it Ok if I keep powered
board on top of anti-static bag, sometimes night times I used to leave
that board on, will be Ok?. Thanks.
Click to expand...

Those silver bags are conductive. You would be better off placing it
directly on your desk without the bag. The box the mainboard came in can
also be used, as long as it doesn't have any "foil" stickers or labels.
 
I don't have anti static mat in my cube, if I place prottype board
(by power on) on top of silver anti-static bag and keep working with
that prototype board?. I turned power on, Is it Ok if I keep powered
board on top of anti-static bag, sometimes night times I used to leave
that board on, will be Ok?. Thanks.
Click to expand...

That should be safe because when I tried measuring the electrical
resistance of those silver anti-static bags, my meter always showed
infinitely high resistance. However I've read that most of those bags
have the anti-static coating only on the inside and that it's possible
to cause static damage by placing a circuit board on the outside of
one. So you may want to turn your silver bag inside-out.

Did your motherboard come with a piece of foam sheet (usually pink or
dark grey)? If so, place the motherboard on top of it because it's
anti-static but doesn't conduct electricity so much that anything will
short out.
 
Did your motherboard come with a piece of foam sheet (usually pink or
dark grey)? If so, place the motherboard on top of it because it's
anti-static but doesn't conduct electricity so much that anything will
short out.
Click to expand...

Don't place your mainboard on anything conductive and power it up.

Are those foam slabs safe? Probably. Do you want to take that small risk
that it might short something out and do damage, or at least skew signals
enough that the board runs flaky?
 
Noozer said:
Don't place your mainboard on anything conductive and power it up.

Are those foam slabs safe? Probably. Do you want to take that small risk
that it might short something out and do damage, or at least skew signals
enough that the board runs flaky?
Click to expand...

If you place it on the foam sheet it might overheat - no airflow under the
board. Best to place it on something known to be non-conductive, but hard
and flat, so there is some air round the board. How about a large book or a
couple of DVD cases (although they might get hot and melt the plastic cover
a bit). If you use a couple of DVD or 4 CD cases, you can leave an airgap in
the middle for good airflow.
 
GT said:
If you place it on the foam sheet it might overheat - no airflow under the
board. Best to place it on something known to be non-conductive, but hard
and flat, so there is some air round the board. How about a large book or a
couple of DVD cases (although they might get hot and melt the plastic cover
a bit). If you use a couple of DVD or 4 CD cases, you can leave an airgap in
the middle for good airflow.
Click to expand...

Or better still, fit several mainboard mounting pillars/spacers and then
stand it on them.
 
That should be safe because when I tried measuring the electrical
resistance of those silver anti-static bags, my meter always showed
infinitely high resistance. However I've read that most of those bags
have the anti-static coating only on the inside and that it's possible
to cause static damage by placing a circuit board on the outside of
one. So you may want to turn your silver bag inside-out.

Did your motherboard come with a piece of foam sheet (usually pink or
dark grey)? If so, place the motherboard on top of it because it's
anti-static but doesn't conduct electricity so much that anything will
short out.
Click to expand...

I know from experience that that's a bad idea. The resistance
of such foams may be so high as to look like an open circuit
to ordinary multimeters, but they do conduct to a minute
degree. Probably not enough to cause permanent damage, but
enough to cause problems if they provide conduction paths
between sensitive points.

Some time ago, I wanted to do a quick POST check of a new
motherboard without fitting it into a case. I installed the
CPU, RAM, switch, PSU and monitor. I've done this many times
before but this time, without thinking, I placed the mobo on
the foam it came with - something I'd never done before.

It wouldn't work. I don't remember the symptoms in detail,
but it wouldn't turn on and POST properly. I'd begun to
suspect that I had a bad motherboard or CPU. Then I woke up,
removed the foam and placed the mobo on the box instead.
Everything worked fine after that.
 
I know from experience that that's a bad idea. The resistance
of such foams may be so high as to look like an open circuit
to ordinary multimeters, but they do conduct to a minute
degree. Probably not enough to cause permanent damage, but
enough to cause problems if they provide conduction paths
between sensitive points.

Some time ago, I wanted to do a quick POST check of a new
motherboard without fitting it into a case. I installed the
CPU, RAM, switch, PSU and monitor. I've done this many times
before but this time, without thinking, I placed the mobo on
the foam it came with - something I'd never done before.

It wouldn't work. I don't remember the symptoms in detail,
but it wouldn't turn on and POST properly. I'd begun to
suspect that I had a bad motherboard or CPU. Then I woke up,
removed the foam and placed the mobo on the box instead.
Everything worked fine after that.
Click to expand...

Agreed, anti-static material like the foam boards are packed
with can prevent proper board operation including failure to
post at all. I've observed it myself and with others who
had placed boards on it.
 
GT said:
If you place it on the foam sheet it might overheat - no airflow under the
board. Best to place it on something known to be non-conductive, but hard
and flat, so there is some air round the board. How about a large book or a
couple of DVD cases (although they might get hot and melt the plastic cover
a bit). If you use a couple of DVD or 4 CD cases, you can leave an airgap in
the middle for good airflow.
Click to expand...

I wouldn't run the mobo for long with it sitting on the foam sheet
(slab?) because of the possibility of overheating. OTOH your
suggestion of using a book or DVD/CD cases could be a lot worse
because they're made of materials that generate a lot of static
electricity (styrene or polypropylene for CD/DVD cases, vinyl or clear
Mylar for book jackets). I like John A's suggestion to install
standoffs on the motherboard to prop it up from the table.
 
GT wrote:

I wouldn't run the mobo for long with it sitting on the foam sheet
(slab?) because of the possibility of overheating. OTOH your
suggestion of using a book or DVD/CD cases could be a lot worse
because they're made of materials that generate a lot of static
electricity (styrene or polypropylene for CD/DVD cases, vinyl or clear
Mylar for book jackets). I like John A's suggestion to install
standoffs on the motherboard to prop it up from the table.
Click to expand...

I usually set boards on a thick magazine or three layers of
cardboard cut from a box. Well actually I always do it,
since all boards are tested before being built into a
system. Putting them on this elevated material merely
serves the purpose of getting the board off the table by a
few millimeters so the card brackets have room to hang over
the board edge.

In some cases where the heatsink is through-board mounted or
attaches to a frame behind the board, I'll put an addt'l
layer of cardboard under the bottom 2/3rd of the board so it
all sits at about the same height, so plugging or unplugging
things doesn't flex the board as the entire back is
reasonably well supported. Standoffs might work in some
situations, but I would not trust that, as pressure on the
board will make the standoff move relative to the surface of
the (table, etc), allowing the board to flex more than it
would in a case with rigidly mounted standoffs.


I've never had a board overheat like that, do not consider
airflow a factor at all, nor any other problems, but if
there were fets on the back, I agree it would be best not to
put the area in contact with any material with a lowish
melting point as even if they stayed cool enough, the
material may be degraded from the heat. It seems fets on
the back are becoming as rare as they used to be though, you
rarely see boards with that layout, configuration, and with
most now at least 3 stages, the heat density is lower.
 
I don't have anti static mat in my cube, if I place prottype board
(by power on) on top of silver anti-static bag and keep working with
that prototype board?. I turned power on, Is it Ok if I keep powered
board on top of anti-static bag, sometimes night times I used to leave
that board on, will be Ok?. Thanks.
Click to expand...

No. They conduct electricity. 'Nuff said.
 
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