ESD on X31 keyboard.

[Arkor]

Just recently (since it's summer) I've noticed that twice touching the keyboard (the ctrl key) has given off electrostatic discharge.

I'm not well educated on ESD, but does that hurt the X31 in any way?

[sjthinkpader]

This is kind of impossible for the high humidity environment of Houston. Are you running the A/C already and the house has low humidity inside?

[rkawakami]

I've locked up a T23 a couple of times via an errant static discharge; typically by sliding into the cloth chair and then touching the system around the right side of the keyboard/Ultrabay. Usually when I notice that I've received a shock, nothing happens to the laptop. As far as any damage is concerned, I don't think that touching the keyboard will lead to any permanent problems. If, however, you directly apply the discharge to any one of the system's ports (or equipment plugged into them), or handle the memory modules, MiniPCI cards or similar printed circuit boards, then yes, you might cause some failures.

[Arkor]

This is kind of impossible for the high humidity environment of Houston. Are you running the A/C already and the house has low humidity inside?

The workshop has the AC running full blast as my quad core Intels get hot, although the humidity is supposedly high.

I could stop wearing socks.

[sjthinkpader]

Most consumer electronics goes thru some level of ESD testing. There are different test specs such as JEDEC for components and systems. ESD discharge may cause the Thinkpad to reset but should not cause permanent harm.

For on chip protection, performance permitting, the I/O pins have a row of diodes before the input circuit for protection. These diodes would take the damage of ESD and allow input circuit to continue working after the event.

It is common practice to use clear plastic cases during testing to see where the discharge ground path went in order to make improvements to ESD resistance. I still have a few clear plastic products packed away in my garage of these past projects. Usually dry area in the middle of winter such as Calgary are considered to be the worst case environment.

[rkawakami]

All of the ICs that I've seen/tested over the years have had input protection diodes on all of the pins (not just the I/Os), with very few exceptions. Those exceptions have been on test pads not normally bonded out to a package pin. One of the basic tests that a test engineer has to do on a device is a continuity check. That insures that each pin of the device is being properly connected to the tester. That continuity check is actually detecting the presence of the input protection diodes.

Very early CMOS devices had poor ESD characteristics such that they would be damaged with shocks of less than a hundred volts or so. Modern process and design improvements have increased this level to several thousands of volts. During my testing career I've only blown up two or three parts, out of many thousands, due to a static discharge.

[sjthinkpader]

Not in consumer products certainly, very high speed chips such as laser drivers cannot withstand the added capacitance of the protection diodes. So the input protection diodes are either sized very small or not implemented.

[sjthinkpader]

...
I could stop wearing socks.

Then it'll be hard to pull off your boots.