How to make USB ports more zap resistant?


L

larry moe 'n curly

Several months ago, a port on an NEC-based USB card failed (a section
of its LM3526 power controller & overcurrent protection chip blew), and
just recently the same happened to an ALI-based USB card. I'm pretty
sure I didn't zap either card with high voltage because I always touch
the outer metal shell of the USB connector to bare metal on the
computer case before plugging it in.

Each USB port has a 100-220 uF aluminum capacitor across its +5V and
ground lines, and the NEC-based card also had a ceramic chip capacitor
in parallel. Is there anything I can change or add to protect USB
ports better? Does it help to use tantalum or low ESR aluminum
capacitors? I installed tantalums on my other USB cards just after the
NEC card blew.
 
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N

NSM

....
| in parallel. Is there anything I can change or add to protect USB
| ports better? Does it help to use tantalum or low ESR aluminum
....

Use a powered hub.

N
 
L

larry moe 'n curly

Use a powered hub.

How does that help when a powered hub costs as much as a PCI USB card
and has ports that are just as vulnerable to zapping as the card's?
 
C

Conor

How does that help when a powered hub costs as much as a PCI USB card
and has ports that are just as vulnerable to zapping as the card's?
Because a powered hub can support a higher load per port than a
PCI/Onboard USB card.
 
J

JAD

larry moe 'n curly said:
Several months ago, a port on an NEC-based USB card failed (a section
of its LM3526 power controller & overcurrent protection chip blew), and
just recently the same happened to an ALI-based USB card. I'm pretty
sure I didn't zap either card with high voltage because I always touch
the outer metal shell of the USB connector to bare metal on the
computer case before plugging it in.

Each USB port has a 100-220 uF aluminum capacitor across its +5V and
ground lines, and the NEC-based card also had a ceramic chip capacitor
in parallel. Is there anything I can change or add to protect USB
ports better? Does it help to use tantalum or low ESR aluminum
capacitors? I installed tantalums on my other USB cards just after the
NEC card blew.
is this with various USB devices or one in particular? I have yet to
do harm to any USB port, on even my oldest machine. All kinds of
different devices- DC's, printers, keyboard/mice, speakers, sound
devices, USB LAN converters etc.
 
J

John Larkin

Several months ago, a port on an NEC-based USB card failed (a section
of its LM3526 power controller & overcurrent protection chip blew), and
just recently the same happened to an ALI-based USB card. I'm pretty
sure I didn't zap either card with high voltage because I always touch
the outer metal shell of the USB connector to bare metal on the
computer case before plugging it in.

Each USB port has a 100-220 uF aluminum capacitor across its +5V and
ground lines, and the NEC-based card also had a ceramic chip capacitor
in parallel. Is there anything I can change or add to protect USB
ports better? Does it help to use tantalum or low ESR aluminum
capacitors? I installed tantalums on my other USB cards just after the
NEC card blew.


Tantalum caps are inclined to explode.

John
 
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N

NSM

| How does that help when a powered hub costs as much as a PCI USB card
| and has ports that are just as vulnerable to zapping as the card's?

What is zapping these? This seems to be unusual? Is the grounding OK on your
systems?

N
 
R

Rob Stow

NSM said:
| How does that help when a powered hub costs as much as a PCI USB card
| and has ports that are just as vulnerable to zapping as the card's?

What is zapping these? This seems to be unusual? Is the grounding OK on your
systems?

It's winter time in the Great White North. -35'C overnight but
it has warmed up all the way to -22'C so far this afternoon.

I hate this time of the year because I have to deal with all the
friends, friends-of-friends, etc., who fry keyboards, mice, PS/2
ports, and USB ports simply by sitting down to use their computer
in a room with 15% relative humidity.

Doesn't matter how often you warn them to use a humidifier. The
knowledge /you/ have acquired over the years means nothing to
them until /after/ they fry something. At which point they
wonder why you never warned them about it before.
 
N

NSM

| It's winter time in the Great White North. -35'C overnight but
| it has warmed up all the way to -22'C so far this afternoon.
|
| I hate this time of the year because I have to deal with all the
| friends, friends-of-friends, etc., who fry keyboards, mice, PS/2
| ports, and USB ports simply by sitting down to use their computer
| in a room with 15% relative humidity.
|
| Doesn't matter how often you warn them to use a humidifier. The
| knowledge /you/ have acquired over the years means nothing to
| them until /after/ they fry something. At which point they
| wonder why you never warned them about it before.

Radio Shack used to sell 'Anti Static Spray' which, AFAIK, was a detergent
solution you sprayed on the carpet. Also, ISTR some sort of grounding pad
you could get which you touched before touching the computer. I suppose some
sort of USB spike suppressor is possible but I haven't seen one so far.

Even in the Lower Mainland, BC, it's -6 C. We don't care for that sort of
thing in Lotus Land. Even the freaks are staying indoors.

N
 
K

Ken Weitzel

NSM said:
| It's winter time in the Great White North. -35'C overnight but
| it has warmed up all the way to -22'C so far this afternoon.
|
| I hate this time of the year because I have to deal with all the
| friends, friends-of-friends, etc., who fry keyboards, mice, PS/2
| ports, and USB ports simply by sitting down to use their computer
| in a room with 15% relative humidity.
|
| Doesn't matter how often you warn them to use a humidifier. The
| knowledge /you/ have acquired over the years means nothing to
| them until /after/ they fry something. At which point they
| wonder why you never warned them about it before.

Radio Shack used to sell 'Anti Static Spray' which, AFAIK, was a detergent
solution you sprayed on the carpet. Also, ISTR some sort of grounding pad
you could get which you touched before touching the computer. I suppose some
sort of USB spike suppressor is possible but I haven't seen one so far.

Even in the Lower Mainland, BC, it's -6 C. We don't care for that sort of
thing in Lotus Land. Even the freaks are staying indoors.

N

Wow, -6 degrees. I feel sorry for you folks; must be
terrible! Shall we send emergency aid? :)

Come and visit Winnipeg. -29 now (mid afternoon; with -34 forecast
for tonight. And that doesn't include the windchill... with
it it will drop to the mid -40's :

Seriously though, if the OP lost two usb ports in as many
weeks, I'd be guessing that he's either extremely unlucky,
or more likely should be looking at what he's plugging into them.

Ken
 
D

daytripper

Tantalum caps are inclined to explode.

That's a mischaracterization.

When they *fail*, they tend to 'splode.
But they don't tend to fail if the application is appropriate...

/daytripper
 
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T

ToolPackinMama

NSM said:
Radio Shack used to sell 'Anti Static Spray' which, AFAIK, was a detergent
solution you sprayed on the carpet.

Get the same effect with liquid fabric softener one part to four parts
water in a spray bottle.

Works great, smells great. :)
 
K

keith

That's a mischaracterization.

When they *fail*, they tend to 'splode.
But they don't tend to fail if the application is appropriate...

....and you don't buy shit. They do get grumpy when inserted backwards
though. That was the real problem thirty years ago. Tants are expensive
though and thus the cheaper leaking aluminums.
 
L

larry moe 'n curly

is this with various USB devices or one in particular?

The NEC card's port blew when I tried a thumb drive, the ALi card with
a Netgear wireless LAN adapter. Neither of those devices was damaged.
 
L

larry moe 'n curly

NSM said:
What is zapping these? This seems to be unusual?
Is the grounding OK on your systems?

Everything is grounded to earth, and I ground the USB connector to the
computer case just before plugging it into the port.
 
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L

larry moe 'n curly

Rob said:
It's winter time in the Great White North. -35'C overnight but
it has warmed up all the way to -22'C so far this afternoon.
Doesn't matter how often you warn them to use a humidifier. The
knowledge /you/ have acquired over the years means nothing to
them until /after/ they fry something. At which point they
wonder why you never warned them about it before.

I'm in Arizona and haven't used any heat yet, and the indoor humidity
was 20% even when it was 4% outdoors (measured with wet and dry bulb
thermometers). I'm sure that the zaps weren't from high voltage (I
touch metal to metal before plugging anything in) but from high
current.
 
R

Rob Stow

larry said:
Rob Stow wrote:




I'm in Arizona and haven't used any heat yet, and the indoor humidity
was 20% even when it was 4% outdoors (measured with wet and dry bulb
thermometers). I'm sure that the zaps weren't from high voltage (I
touch metal to metal before plugging anything in) but from high
current.

When it gets as cold as it has been today, it is not unusual to
have 80% r.h. outdoors, but 10% to 15% indoors if a humidifier is
not used. You drink a *lot* of water when you visit someone who
doesn't use a humidifier.

At such places, it is not unusual to see huge freaking blue-white
sparks fly if you walk across a carpet and then reach out towards
something grounded.

Dogs learn quickly to stay away from children. ;-)
 
L

Lee Waun

N
Wow, -6 degrees. I feel sorry for you folks; must be
terrible! Shall we send emergency aid? :)
No no need to panic. The cold spell has ended and it is raining and 6
degrees out. Luckily the rain is now melting that snow we had. We have
bylaws outlawing snow here. Snow is for the rest of the country. We don't
allow it here.
Come and visit Winnipeg. -29 now (mid afternoon; with -34 forecast
for tonight. And that doesn't include the windchill... with
it it will drop to the mid -40's :
Only fools and my brother and sister live in Winterpeg. There is a reason it
is called winterpeg.
 
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