[Gllug] Memory errors

[Chris Bell]

On Wed 26 May, Pete Ryland wrote:
> 

> 
> The most frequent cause of component failure is ESD[1], but usually that
> doesn't manifest itself until weeks or months afterwards.  This is called
> "latent failure"[2].
> 
> So how many people do /you/ know who complain of short lifespans of devices,
> yet don't take precautions when installing kit, claiming that their handling
> of components doesn't damage them? ;-)
> 
> But I'm sure Tet was careful when installing the RAM though, just thought
> I'd make a point. :-)
> 
> Pete
> 
> [1] Electro-Static Discharge, caused by handling components with
> statically-charged hands/tools.
> 
> [2] See http://www.esda.org/basics/part1.cfm

   If you move a sensitive meter probe around your dry skin you will often
find that the voltage does vary, possibly coincident with nerve ends. Even
wearing a grounding strap does not prevent this, but the voltages are
usually low as long as you first ground yourself to the outside box. It is a
bit like the static that you notice as you get out of a car, you are charged
relative to the car as you slide across the seat unless you earth yourself
to the car body while you are climbing out.
   I had to avoid wearing clothes which generated static electricity,
especially early man-made fibres, and we had to treat some carpets with
anti-static spray or cover them with antistatic mats, but most modern chips
now have integral clamp diodes on external connections so even FET's are
fairly well protected.
   On the other hand, take a close look with a magnifying glass at the
soldering on larger motherboard components such as connector strips. The
board is only supported at a few points in the box, and is easily stressed
as cards are inserted. Some components such as memory cards can be inserted
before the motherboard is placed in the box, but others including PCI cards
must be inserted later. This can cause the motherboard to fail as it flexes.

-- 
Chris Bell

-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug