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Subject: Re: Major Technical Problem
From: Neon John (johngd_at_bellsouth.net)
Date: 2003-07-29


You may be screwed now. If you'd asked before powering it back up...

The problem is that the water treatment chemicals leave a conductive coating
on the boards. They also tend to be hygroscopic. the result is when you
apply power the PCB traces that are exposed start to slowly electrolyze away.

If you can kill power to the unit immediately after getting it wet, most times
the electronics are salvageable. When I worked in a 2-way shop, I used to
have almost 100% success with the following technique on pagers and radios
that had been dunked in "stuff" as long as the user immediately removed the
batteries after recovering the unit.

Open the unit and flush everything (not the hard drive enclosure itself) with
pure grain alcohol, the stuff you can get at the liquor store. Sure, more
expensive washes are available but PGA is fairly cheap in comparison and
leaves absolutely no residue of its own. Following the alcohol wash, wash
everything with distilled water, using copious amounts. Use low pressure
compressed air to blow the water out from under components on the PCBs and
generally dry things off. Place the parts in an oven and bake for several
hours at about 150-175 deg with plenty of air circulation. Watch out for soft
plastic parts. My setup is a cardboard box with a heat gun blowing in through
a hole in the side.

With that brief an exposure, the water should not have gotten into the hard
drive, though it may have melted the HEPA filter shut. If it did unfiltered
air may infiltrate through other pathways. The long term prognosis therefore
may not be good for the drive.

Since you've powered the unit, you're going to have to take it apart and look
for corrosion and deposits on the PCBs and connectors. Generally white or
blue/green powdery residue. Look particularly around the USB port and related
components. If the traces have not been completely eaten in two, you can
generally remove the residue with PGA and an acid brush or well used
toothbrush, followed by the distilled water wash and dry.

On Tue, 29 Jul 2003 01:34:26 -0400, "Tom Izzo" <izzo1701_at_cox.net> wrote:

>Hello. I have recently dropped my Archos into a 4 foot above ground swimming pool. It was underwater for 1 second. I have let it dry out for 4 days. It appeared to be operational again. It was playing things fine. I then hooked it back up to my computer to add some files. After unhooking it, when turned on, it gets stuck into "USB Mode" and I cannot do anything. Everytime I turn it on, regardless of being hooked up to the PC or not, it reads USB Mode. Is there any fixing this, or am I screwed?

---
John De Armond
johngdDONTYOUDARE_at_bellsouth.net
http://bellsouthpwp.net/j/o/johngd/
Cleveland, Occupied TN



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