[ltp] TP Yoga - touchpad psmouse lost sync, buttons hanging / freeze

Nicole Faerber linux-thinkpad@linux-thinkpad.org
Mon, 04 Aug 2014 10:31:01 +0200

Am 03.08.2014 23:53, schrieb Martin N:
> Lo,

> At 16:45 31/07/2014, you wrote:
>> Is it normal that Lenovo service people do not use ESD protection? I was
>> really amazed that the guy not even bothered to ground himself nor the
>> workspace while handling ESD sensitive parts.
> Having worked in a couple of PC workshops it is normal for no ESD wrist
> strap to be used.
> I have seen an ESD mat used however in one shop but it was not mentioned
> in training.
> Dont know about Lenovo but ESD protection seems to be done mainly in
> classes rather than
> in the real world.

Sure, but just because nobody does it does not make it right either?

I am working professionally in the electronics business for more than a
decade now and every company I now that either makes devices or does
service has pretty strict ESD protection rules. Well, this is not PC
industry, it is rather embedded devices. But I would count a notebook as
an embedded these days. And once you have seend ESD damage to silicon
you know that this is the least you want to do to ensure lowest possible
failure rates. The issue is less the immediate defect. This can be found
and fixed pretty reasily. The more severe problem are the mid and long
term faults. The chip's silicon can be damaged in a way that that
develop into measurable failures over time. But then it will be hard to
trakc them down to the ESD damage again.

Handling an assembled and soldered PCB like a main board or graphics
card will in most cases be OK and there are usually enough capacitors on
them to buffer the discharge and bring it quickly down to voltages that
will not cause damages by disruptive discharge. But such capacitors
and/or protective diodes and resistors cause higher power consumption so
the more low power it gets the more delicate the devices get to handle -
e.g. I would not touch a DDR3 RAM module with bare hands without
properly grounding myself before.

Doing ESD properly is not a great deal. It almost does not cost any
extra money and is usually no big deal to execute. It is more a matter
of will and not resources.

Oh well, the service company is working on it and I expect this to be
fixed this week. Let's hope that the next service guy is better trained
and more careful.

> Martin

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