Mobo sitting on antistatic bag

  • Thread starter Thread starter markjen
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markjen

Someone gave me the advice that when you build up a system on a workbench
for checkout and config, set the mobo on the foam and anti-static bag it
came in so that it's cushioned and protected from static. Well, I've been
having weird hangs with no rhyme and reason, so I decided to just set the
mobo directly on a piece of cardboard on the bench. My problems seemed to
clear up immediately.

I did a little reading and these antistatic bags are mildly conductive - I
noted about 500 ohms resistance if you measure across an inch of the grid on
the bag. Me thinks that setting the mobo on the bag wasn't such a great
idea. At least that's my theory for today's problems.

- Mark
 
Someone gave me the advice that when you build up a system on a workbench
for checkout and config, set the mobo on the foam and anti-static bag it
came in so that it's cushioned and protected from static. Well, I've been
having weird hangs with no rhyme and reason, so I decided to just set the
mobo directly on a piece of cardboard on the bench. My problems seemed to
clear up immediately.

I did a little reading and these antistatic bags are mildly conductive - I
noted about 500 ohms resistance if you measure across an inch of the grid on
the bag. Me thinks that setting the mobo on the bag wasn't such a great
idea. At least that's my theory for today's problems.
Click to expand...

AS bags are of course conductive, that's how they work-by draining away
ESD. Never turn on the mobo while it's sitting on one, as you will
short every pin to every other pin. You're very lucky it still works.
 
I think probably he mean't you should have your mobo on the antistatic bag
as you build your system... putting in the chip and ram... before you put it
into the case. Antistatic bags are conductive. That's what I do... i put
in the few parts while the board is on the antistatic bag... then put
everything into the case.
 
Kenny said:
Don't forget that the antistatic bag and/or yourself must be grounded!!
Click to expand...


I missed the first part of this thread, but yeah - antistatic bags are
conductive, otherwise they could build static... and that means that if you
fire up your motherboard on it, you are likely to have problems.

Ben
 
Ben said:
I missed the first part of this thread, but yeah - antistatic bags are
conductive, otherwise they could build static... and that means that if you
fire up your motherboard on it, you are likely to have problems.
Click to expand...

I'd say not as likely as one might think. Anti-static bags have a pretty
high resistance, which is enough to drain off static charges (usually in
the region of thousands of volts), but on a mo/bo you usually don't have
voltages of more than 5 or 12 volts to begin with, so leakage currents
would be quite minimal (particularly compared with the currents that
regularly flow on the board). If I had to put the mo/bo onto something
and operate it, I'd use a wood or cardboard surface.

Stephan
 
Stephan Grossklass said:
I'd say not as likely as one might think. Anti-static bags have a pretty
high resistance, which is enough to drain off static charges (usually in
the region of thousands of volts), but on a mo/bo you usually don't have
voltages of more than 5 or 12 volts to begin with, so leakage currents
would be quite minimal (particularly compared with the currents that
regularly flow on the board). If I had to put the mo/bo onto something
and operate it, I'd use a wood or cardboard surface.

Stephan
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Click to expand...

The OP said they measures 500 ohms across an
inch. The resistance of all the static bags I've
measured is in the Meg ohm range. I just tried
to measure one with my cheap meter (highest
range is 2 meg ohms) at home. It shows open no
matter where I place the leads.



and it shows open no
 
I used to make conductive packaging for the pharmaceutical industry,
resistance was typically 10^4 to 10^5 ohms to pass QA.
Click to expand...

I was just using a cheap Radio Shack ohmmeter and got around 500 ohms on the
main grid an inch or so apart for the bag that the ASUS mobo comes in.

Thanks for all the comments guys. My mobo has been working for a couple
days without the slightest issue while sitting on cardboard. So putting the
thing on the bag didn't make it fail and it even allowed me to build up the
system, but appears to have caused random minor problems now and then.
Definitely not recommended!

- Mark
 
markjen said:
Someone gave me the advice that when you build up a system on a workbench
for checkout and config, set the mobo on the foam and anti-static bag it
came in so that it's cushioned and protected from static. Well, I've been
having weird hangs with no rhyme and reason, so I decided to just set the
mobo directly on a piece of cardboard on the bench. My problems seemed to
clear up immediately.

I did a little reading and these antistatic bags are mildly conductive - I
noted about 500 ohms resistance if you measure across an inch of the grid on
the bag. Me thinks that setting the mobo on the bag wasn't such a great
idea. At least that's my theory for today's problems.

- Mark
Click to expand...

I build computer with my motherboard sitting on carpet, wool mittens, and 2
cats under my arm. :)
 
I used to make conductive packaging for the pharmaceutical industry,
resistance was typically 10^4 to 10^5 ohms to pass QA.
Click to expand...

I was just using a cheap Radio Shack ohmmeter and got around 500 ohms on the
main grid an inch or so apart for the bag that the ASUS mobo comes in.

Thanks for all the comments guys. My mobo has been working for a couple
days without the slightest issue while sitting on cardboard. So putting the
thing on the bag didn't make it fail and it even allowed me to build up the
system, but appears to have caused random minor problems now and then.
Definitely not recommended!

- Mark
 
I missed the first part of this thread, but yeah - antistatic bags are
conductive, otherwise they could build static... and that means that if you
fire up your motherboard on it, you are likely to have problems.

Ben
Click to expand...

How about the foam?
 
-|- said:
How about the foam?
Click to expand...

Providing it's non-conductive...

I find the case to be the best place in all fairness. If I did want to run
the motherboard out of the case for some reason I'd probably just choose my
desk (worktop).

Ben
 
Someone gave me the advice that when you build up a system on a workbench
for checkout and config, set the mobo on the foam and anti-static bag it
came in so that it's cushioned and protected from static.
Click to expand...


BAD, BAD advice.

"Silvery" anti-static bags are NOT protected on the OUTSIDE.

Placing a sensitive electronic device on the outside of a silvery
metallized bag is probably the WORST thing you can do.


The black "checkerboard" style bags, which it sounds like you have,
ARE protected on both sides, so it's probably OK to use them as a
cushion (but NOT while power testing the board!).


And the bag and work surface needs to be properly grounded for there
to be any protection from static anyway.


BobR
 
Providing it's non-conductive...

I find the case to be the best place in all fairness. If I did want to run
the motherboard out of the case for some reason I'd probably just choose my
desk (worktop).

Ben
Click to expand...

Same here! ;P
eD
 
[snip]
Indeed, the resistance IS pretty high... I should have said "could" have
problems.
Click to expand...

I used to make conductive packaging for the pharmaceutical industry,
resistance was typically 10^4 to 10^5 ohms to pass QA.

HTH

Ian
 
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