ESD procedures???

[SteveDeBeave]

Most of us know to use a wrist strap for ESD reasons. We clip it on our case or psu when we work on the computer. What if your building a new puter? Should we clip on to a grounded unit like a plugged in (grounded) computer near the work area that we use?

I'm thinking about when we are pulling the motherboard out of the bag for the first time, if we ground out to that new case sitting on the table we are not grounded. The new case is not plugged in to the power receptacle so it's not going to attract an ESD, right?

Any ideas on proper procedures for ESD?

Steve

 

[pm]

ESD is electrostatic discharge. The worry is that your body could pick up static and that charge could arc onto an electrical component and the several thousand voltage charge that static arcs contain can fry the electronic component on the motherboard. So if you tie yourself to ground, you discharge all static into the ground strap before you build up a charge.

I plug the power supply in but turn off the master switch on the power supply (so it can't turn itself on when I'm installing the motherboard). But this solution occassionally makes people nervous. You need to attach yourself to ground so you could tie into a water line pipe, or a radiator, or I have seen plugs that plug into the ground connection of outlets.

 

[SteveDeBeave]

So if you hook that wrist strap on a computer case that's not plugged in...........YOUR NOT GROUNDED. You could still get a static charge to parts your touching.
The ground strap needs to be hooked up to a computer case that is plugged in with a U ground plug! Man I can't imagine how many problems come from ESD because people ground to a case thats not plugged into a grounding source!

 

[pm]

The idea is that you want something that can sink charge. And a metal case on a table doesn't really sink charge that much better than a regular person does. So, yes, you need to have it plugged in - or you need to plug yourself into something that is tied to ground or that can sink a lot of current. A pipe, a water faucet, a metal fireplace, the ground on a grounded outlet, a radiator or heater vent. These will all work pretty well.

ESD is more common and a larger problem than people probably think. I worked on the test floor at Intel for a while and I learned that it doesn't take much to fry a chip - or a $750k tester. There were signs everywhere. I remember when one of my co-workers touched one of the tester boards on an IMS FT tester (think: expensive) without a grounding strap and nuked it pretty much completely so that it couldn't be used for a week while a technician replaced chips. It was a big deal.

And before that, I remember I nuked one of our latest prototypes microprocessors once... We'd spent 36 hours FIB'ing it (rewiring a silicon chip with a multi-million dollar gizmo), we tested it, it was working great and a coworker and I were carrying it from the FIB lab to the test lab. He said he needed to do something, handed it to me, and I could feel the shock through my fingers. Got it on the tester and it was thoroughly dead. One less priceless prototype in the world. I have strongly respected ESD ever since.