[ale] tech "magic"

[Geoffrey]

Neal Rhodes wrote:
>> Everyone here has had it happen. Something fails and you get called to
>> "take a look at it". You get there. take it and it isn't working. So
>> you methodically take it apart, inspecting everything alonmg the way
>> looking for failure points and find
> 
> I keep swearing I really do software, but somehow I've spend a fair
> amount of time in factories and other grungy places.   
> 
> Yesterday I was installing a new server in a warehouse of vintage
> British Motorcycle parts.    Had two Epson printers that were failing to
> power up. 
> 
> My experience is that dust, especially factory dust, CAN CONDUCT some
> electricity. 
> 
> With both printers, after the client was ready to take them to a repair
> shop,  I removed the covers, blew out the dust really good, checked the
> fuse, put it back in, and wiggled the board connector.     Voila.  My
> diagnosis - contact resistance and slighty conductive dust bunnies. 
> 
> Then the owner's desktop fails to come up, beeping a single long bleat.
> Again, owner about to drive it to Windy Hill, the dealer said that was
> battery bad.  I said let me take a quick look.  Re-seat the RAM, tested
> the button battery, it was fine, wipe it on my shirt, stick it back in,
> and voila, it comes up fine. 
> 
> As a result, my theory is that if it's not soldered, it's a suspect
> connection.

Oh, but after a few years in Quality Assurance, I can say, "if it's 
solder, it's a suspect connection."  I've seen many a cold solder..

> 
> Some of us old enough to remember Altos boards with 7400 series logic
> can remember that the chips would try to crawl out of their sockets at
> night, and first thing to do after blowing out the dust is push all the
> chips back down.   Glad those days are over. 
> 
> Neal Rhodes. 
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-- 
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
  - Benjamin Franklin