View Single Post
  #5  
Old February 17th 14, 10:45 PM posted to microsoft.public.windowsxp.hardware
Paul
external usenet poster
 
Posts: 18,275
Default Fixing inconsistent RAM detection

BillW50 wrote:
In ,
Paul typed:
BillW50 wrote:
On 2/17/2014 4:31 AM, jphilippa wrote:
I have two identical 1Gb RAM chips installed, and they are not
always detected. I have even had both BIOS and WIN say that RAM is
1.5Gb [as well as 1Gb and 2Gb]. Swapping the chips around seems to
fix it for THAT session, and then what is detected at next reboot
is an adventure/uncertain.
Try cleaning the RAM contacts with a clean pencil eraser. Hopefully
that would take care of it. Don't use other cleaners until you try
the eraser trick first. As this one seems to last the longest.

I generally recommend against this, for a first step.

[...]
c) Only under the most dire circumstances would you apply an
abrasive. If the 10u gold plating is completely shot, perhaps
grinding the **** out of it with your pencil eraser is your
only option. Be prepared to have to do this, every few months.
It is habit forming.


Actually I have found just the opposite. I learned this trick with a
pencil eraser first with those old TV tuners with mechanical contacts
from a very seasoned repairman. They were very sensitive to the
slightest contact problem. And there was two ways this was usually done.

1) The easy way. Pull the tuner knob off and spray inside with contact
cleaner and turn the selector around until all of the selections were
nice and clean.

2) The hard way. Removing the back of the TV. Removing the tuner.
Disassembling the tuner. Using a pencil eraser on each and every
contact. There is like a hundred of them. Put it all back together and
your done.

The difference between the contact cleaner/alcohol and the eraser method
was huge. As the former the problem would come back in about 6 months.
Repeat and maybe it would last 5 months. Repeat again and now it would
last 4 months. Get the idea? Do it once with the eraser and it would
last 20 years before the problem ever came back again even in a smoke
filled house. That is huge!

And it works on any kind of electrical contact. The only thing it is
worthless on is grimy and oily contacts. As all it does is contaminate
the eraser and makes it useless. So then you must use other methods.

Nor have I seem any evidence that a pencil eraser acts as an abrasive on
tin, copper, or gold. Did you ever see any evidence of that Paul? Even
under a 50x microscope I can't see any micro scratches or anything. All
it does is to remove oxidation and dirt. Maybe next time I am by a
scanning electron microscope, I can check again at say 100,000x
magnification if it does act as an abrasion. But I still don't think so.

And if you know about the hardness factor, I am sure you will find that
an eraser is softer than tin, copper, or gold. And in physics, it is
impossible for a softer material to scratch a harder one. An eraser
works on paper because the eraser is harder than the paper is. An eraser
on tin, copper, or gold is only going to remove the oxidation, dirt,
dust, etc.and wear down the eraser.

Problem with cleaners in general is they are never 100% pure. And they
will often leave a slight usually sticky residue. And they attract dirt,
dust, etc. like a magnet. Sure it works for a time, but you will have to
do it again and again later.

Tin on tin is the worst. If you even have to use the eraser trick again
and again (usually only happens on tin to tin), because it oxidizes very
fast. And I hope I got this right is a dielectric paste. Anyway the same
kind they use in boat trailer tail light bulbs and sockets. As it keeps
dirt, water, air, etc out and yet still allows contact. This works well
for those troublesome tin contacts.


You're comparing a rotating assembly in a dirty environment,
to a DIMM making contact with a socket once. Once the contact
is made, the dust swirling around it doesn't matter (within reason).
A moist corrosive atmosphere and packed dust, does matter.
Corrosive atmospheres exist in industrial settings.

Due to the cheapness of the gold plating on computer electronics,
there is always the possibility of pinholes in the finish. I've
seen it on products I've bought here. In the telecom industry,
we specified 50u gold finish, and that provides a measure
of margin. The 10u gold finish computer stuff uses, with pinholes
in it, is a definite compromise. I still don't see an incentive
to use abrasives on it though. The metal underneath the gold,
is no substitute for the gold.

And tin on tin is fine. The only point of mentioning the
two systems, is to mention not to mix them. Many years ago,
there was the possibility of a consumer mixing the metals.
DIMMs now are gold on gold, even if the gold is a wee bit thin.

I don't even need a microscope. The gold finish has pinholes
even when it's new. I don't even need to look for it. Have
you ever seen an improperly plated video card, with gold
missing entirely on some of the pins ? I have. I don't need
a microscope for that. A pencil eraser is an abrasive.
The kind on the end of a pencil, the pink eraser. It's
abrasive, as it'll rip a sheet of paper to shreds after
you've used it a bit. And if you use a gum eraser, it
could leave residue behind.

If you use no chemicals at all, and just re-seat the
DIMM, there's no chance of a chemical residue left
behind. That's why I treat it as the number 1 option.

When I bought a new computer, and the Ethernet cable
wasn't making contact with a pin on the back of the computer,
inserting it five times was enough to clean the computer
pin. And I never had any further trouble with it.
No chemicals. Wiped clean by the connector action.

Paul
Ads