In NewtonTalk V1 # 11, David Humphreys made the following comments.....
>As I follow the threads on this subject, it seems that people are generally
>experiencing this after an upgrade or screen replacement.
>The board is certainly removed for screen replacement and may or may not be
>removed for memory upgrade (depends who does it).
Gee, thanks David for insinuating that the MP2000 Upgrade ( I'm the only US
source )
causes the "jaggies problem".
Apple hasn't provided the upgrade in 2 years so you must be talking about
me.
In the future, get your facts straight before broadcasting misinformation.
If you've spent any time reading the comments of people experiencing this
especially on discussion boards ), you'll see that it has several possible
causes. Upgrading the D-Ram is NOT one of them.
Possible Causes :
1. The Touchscreen "delaminates" in areas over time due to regular use.
2. Slight warping of the bezel edges puts light pressure on touchscreen
edges.
3. Corrupted system "soups" have also been reported to cause it.
4. Grit or dirt particles wedged between the touchscreen and bezel exerting
pressure on the touchscreen.
>The flex connection, as has been observed, is a compression type and relies
on
>the intimate contact of two surfaces. Oxidation of the contacts on the flex
>is a real possibility.(Don't do repairs while eating Doritos;-))
The PCB pads to connect the touchscreen are gold plated. Gold does not
oxidize. The "tail" contacts on the touchscreen are tin. Though tin can
oxidize on the surface a little, cleaning away what little is there has no
effect from my experience.
Note :
When Apple was performing upgrades, they flooded the boards with solvent.
There is a possibility ( in my opinion ) that some contamination could have
settled in the touchscreen related region of the board. This is only
speculation though. I would guess that humidity increases might reactivate
the flux that remained and cause problems. Over the years I have seen some
of the water soluble fluxes cause severe impedance problems with certain
types of circuits.
When I upgrade MP2000's, I do not touch anything outside the D-RAM area.
In several hundred upgrades over the course of 2 years, I have NEVER had a
customer comment that his/her unit now started exhibiting "jaggies" after
the upgrade.
David Watson
a.k.a. "Dr. Newton", "Digital Ocean Dave"
drnewton@kc.net
http://www.kc.net/~drnewton
Provider of the MP2000 Upgrade
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