Random bits:

This web page contains random bits related to things technical - mostly having to do with repair/fixing of things -  that don't fit anywhere else on my web site.

A few words of caution/warning:

Adobe Flash will install without error, but won't work on Firefox or Seamonkey.

Sony TRV730 camcorder throws a "C:31:something" error when loading a tape.

Camera Images on a Sony DCR-HC42 camcorder start to get erratic/flaky and then finally disappear.

Images on a Polaroid X530 camera started to get erratic/flaky and then finally disappeared.

The "Take Picture" button on a Nikon Coolpix L5 camera no longer works - or it only works sometimes.

My laptop started crashing more and more frequently - but then I noticed that if I never touched it, it would be fine...

Now, the cynical would say that this sounds like every Windows (tm) machine ever made - and that was my first thought that there was some errant driver, bad memory, loose connection.  It *seemed* at first that the "busier" it was, the more often that it would crash, but then I would leave the laptop alone when it was crunching something (e.g. rendering video, sound, printing, etc.) and it would *never* crash - unless I touched it.  In the process, I checked drivers, re-seated connectors and everything else - but to no avail.

I finally realized that if I had ANY static on my finger at all and touched the computer, it would either lock up or reboot the laptop!

It didn't used to do that!  I remember that it used to be that I could discharge a pretty good "zap" to the laptop from static (on carpet, etc.) and it wouldn't flinch - so what changed?

That wasn't a good sign!

I carefully disassembled the computer far enough to be able to lift the "top" half of the plastic case that had the keyboard/mouse pointer/aluminum plate and looked at it carefully to see how that plate was supposed to be grounded to the rest of the chassis.  In two places - one next to the CD/DVD drive and another next to the memory card reader -  I noticed some pieces of metal mesh tape and in feeling around, I could tell that there was a hole in the plastic case beneath the tape that provided access to the bottom of that aluminum plate, the idea being that these would make contact with the metal bodies of the disk and card readers.  Using the ohmmeter again, I checked for continuity between that mesh and the plate and there was none unless I pressed firmly on it - and that was true for both places where this metal mesh/tape was located.

I carefully peeled off the mesh/tape and saved it and this revealed a small foam-filled roll of this mesh:  The idea was that this piece would connect the metal plate to the tape, bridging the gap left by the thickness of the plastic shell.  Apparently, either due to oxidation, loss of elasticity, or something else, the metal mesh wasn't making reliable contact any more and thus, that aluminum plate wasn't grounded.  When I touched the computer's case with just a little bit of static, this caused a discharge as the static would jump the small gap between the plate and the portion of the mesh that wasn't making contact.  This may have also caused a sudden, changing electrostatic field in the space over the motherboard (e.g. the portion covered by the plate) which resulted in an EMI-type spike, crashing the computer.

To fix this, I used some "Nickle Print" solution and "painted" inside the two recessed areas where the mesh had been.  This nickle print is a solution that contains micro particles of nickle metal that, when painted on a non-conductive surface, will dry into a conductive paint.  By painting this area I increased the probability that some of that piece of mesh tubing (to be installed later) would make contact with the aluminum plate, plus it added a slight amount of thickness.

Once the nickle print cured, I reinstalled the foam-filled mesh tubes and the pieces of  mesh tape  and verified that they had very good ohmic contact with the top plate.  Upon reassembling the computer, I re-checked the resistance between that metal plate and the computer's chassis and found it to be in the 2-3 ohm area - including lead resistance.

Now, I can walk up to the computer and "zap" it without it even noticing - and it hasn't crashed since!

I suspect that this problem has been occurring for a while with the plate-chassis continuity degrading over time.  As winter set it and the humidity dropped (often below 20%) the likelihood of static discharge increased.

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This page is copyright 1999-2012 by Clint Turner.  All rights (and wrongs) are reserved.

This page maintained by Clint, KA7OEI.  Last update:  20120306

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