RE: ~e; deconstructing electronics: PDA cradle

["Mike McPherson" <mike@mcpherson.net>]

All,
  I'm a little late on this post, but I hope you find it useful.

Taking things apart is a favorite pastime of mine.  I think this passion
started when I was young, probably out of curiosity of how things worked and
were put together.

Today I mostly take electronic devices apart for salvaging purposes. I can
literally spend hours doing this.  With an old TV and a de-soldering iron
(or just a cheap Weller 25 Watt iron and a pair of needle nose pliers) I can
amuse myself for hours.

It's almost like a treasure hunt or something.

Anyway, I wanted to share some tips and tricks I've picked up over the
years, mostly from trial and error.  These hints should apply to the range
of seasoned repair technicians as well as first timers.  

1. Your work bench or desk area should be clean as possible (i.e., no
clutter) and ideally perched on top of a smooth surface or concrete.  Avoid
any form of carpeting.  The floor turns out to be a place you spend more
time than you might think (it's the place where the little items like
screws, springs, etc. inevitably fall.  

2. If you can arrange for a simple uncluttered area that is painted all
white (or close to it), hunting for dropped or misplaced parts becomes much
easier.

3. As soon as a part springs from your control, use martial arts eye
movement to follow the trajectory.  The same goes with your ears.  For
example, the sound of metal against concrete is significantly different that
plastic against metal, and so on.  This helps you track the part.

4. A metal cup like a mint container is very useful to confine certain
extracted parts.  When more tools creep their way into the work area, they
tend to obstruct things (even other tools!).

5. If the case on the item you are taking apart has many screws of different
sizes, lay them out on the workbench in a physical pattern as they would be
reinstalled.  In other words, space them out on the bench like they are
installed on the cover.  This gives you a location map for reinstallation
(if reinstallation one of your goals :-).

6. For plastic cases that snap together, the press fit tabs can be located
by running your thumbnail down the separation groove that is used in most
plastic injection molding designs.  Once located, your goal is to reduce the
mangling of the surrounding plastic as much as possible.

7. Use a thin blade flathead screw driver combined with a suitably wide
chisel or a wide and thin flathead screwdriver (very hard to find - that's
why I mention the use of a chisel).  Push down on one tab while gently
twisting the chisel to widen the gap. Do this while the case is pressed
against the bench.  *Note*: never put any apart of your body in a potential
landing zone where a tool that slips from you hand may end up (especially
with a chisel!).

8. With the advent of cheap digital cameras, complex devices can be
photographed as you dismantle it so you don't have to sketch the layout or
memorize it.

9. A permanent magnet is useful for confining screws that are not stainless.
The screws will become slightly magnetized which allows you to place them on
the end of the screwdriver and reinstall with one hand behind your back.
The same technique will work if you rub the tip of the screwdriver back and
forth over the magnet.

10. Use whiteout as a paint or marker to identify key areas.  For example,
if you pull a 32 pin ribbon cable off a connector, use the whiteout to mark
PIN 1 or mark both the cable and connector side in a fashion that you can
only line them up one way. The beauty of whiteout is that a) it dries fast,
b) you can write on it with a pen, and c) you can always just scratch it off
with your fingernail.

11. Use an eraser to clean oxidized connectors like battery pins or edge
card connectors.  A white plastic Stadler-Mars, or pretty much any soft
architectural eraser are both excellent tools for cleaning oxidized
contacts, although sometime you may need a mechanical pencil eraser or
similar to get into tight places.  The first thing I do before building any
electronics kit is to clean the PCB board copper traces with an eraser.
Soldering becomes much easier and makes for superior connections.  I also
clean the tip of the soldering iron before soldering each point with a brass
wool tip cleaner.  Flux dipped brass wool efficiently cleans tips without
drastic temperature drop and extends life of any soldering iron tip. 

12. If you can't get your device back together and are fed up with the whole
exercise, you always can send it to me for salvage :-)

Happy exploring!

Best regards, 
 
/// Mike

-----Original Message-----
From: info@electronetwork.org [mailto:info@electronetwork.org] On Behalf Of
brian carroll
Sent: Sunday, August 15, 2004 1:43 PM
To: electronetwork-l@openflows.org
Subject: ~e; deconstructing electronics: PDA cradle

Hi everyone, I took apart a bunch of stuff a few weeks ago
as I am planning to demonstrate an approach to learning
more about electronics (and how hardware and software
connects) through the dismantling of the artifacts in the
attempt to get a glimmer of conceptual understanding,
however slight, about how these things operate from the
viewpoint of a novice in search of something meaningful
in the electronic wasteland of junk that is all around today.
So here's the first, probably most in-depth of future such
excavations of electronics as an embodiment of ideas:

Deconstructing Electronics: The PDA Synchronization Cradle
http://www.electronetwork.org/education/decons/pda.htm

Did not think it through completely and dismantled and
recycled parts of things that could have been presented in
a more 'whole' manner, so kept only some really neat little
artifacts from computer speakers, floppy and harddrives,
and such, and did not document the dismantling process.
Though, there is a keyboard, Zon/credit-card machine, a
small pager, (maybe) calculator (my beloved HP 20 S is
nearing the end of its life, sadly), and some other high-tech
items that are in a different category of exploration, such as
an IC silicon wafer, IC dies, a MEMs mirror assembly, and
other things that are more towards comparing high-tech
with high-art or at least to question this aspect in artifacts
(that is, where is the dividing line between art and artifact?).
One thing I learned, besides that this is a lot of fun, and that
I am glad I studies up on what to do (UNPLUG!) and not do,
only after the fact (don't handle printed circuit boards with-
out gloves, then touch your face, as chemical burns result!).
In any case, here's a sampler and have photos for others,
and other sections of the electromagnetic education
website, at: http://www.electronetwork.org/education/
comments, feedback, suggestions appreciated.
thanks, brian

  brian thomas carroll: architecture, education, electromagnetism
  http://www.mnartists.org/artistHome.do?rid=13102
  http://www.electronetwork.org/bc/

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