I think Bob Smith offers good advice on the cleanup. I want to comment
on the battery.
I have never heard of a lithium battery explode unless you try to
charge one. There are two types of lithium batteries. The lithium ion
battery is rechargeable while the standard lithium battery is NOT
rechargeable. Is there a possibility your company got the two types of
batteries mixed up and is trying to charge a non-chargable type lithium
cell? If so this can be very dangerous. Lithium batteries burn like a
flare and water execrates the fire rather than quenching the fire.
Make sure you have removed all the lithium before you cleanup as Bob
suggests.
Fred Townsend
Bob Smith wrote:
Try soaking in a warm solution of ordinary domestic baking soda and
distilled water. Brush gently with a soft brush from time to time to remove
all loose residue. Continue until board is clean.
Sodium Bicarbonate is a mild base and will neutralize any acidic residues.
Rinse very well in warm water to remove any residues.
Allow board to soak in warm distilled water, agitate occasionally Distilled
water will disperse and dilute any neutral ions.
Gently shake board dry.
Air dry in a warm oven (about 150 deg F) . Almost any electronic part will
withstand 100 deg C storage temperature, but be careful of any little
plastic bits that might soften.
Warning - most domestic ovens regulate very poorly on the 'Low' setting and
will severely overheat, especially when heating up.
You can make a very usable drying oven out of your wife's(proceed with
extreme caution) hair dryer and a clean cardboard box. Stick hair dryer
nozzle through side of box. Adjust heat setting for desired temperature.
The air circulation from the dryer also helps a lot.
When board is _absolutely_ dry, power up and pray a lot!
Good luck, Bob Smith
--- Avoid computer viruses, Practice safe hex ---
-- Specializing in small, cost effective
embedded control systems --
http://www.smithmachineworks.com/embedprod.html
Robert L. (Bob) Smith
Smith Machine Works, Inc.
9900 Lumlay Road
Richmond, VA 23236 804/745-1065
[EMAIL PROTECTED]
----- Original Message -----
To: "Multiple recipients of list CHIPDIR-L" <[EMAIL PROTECTED]>
Sent: Saturday, April 17, 2004 12:49 PM
I have a board which had a lithium battery explode unseen and was not
noticed until we attempted to power it on (quite some time later,
possibly a year or more...). The PCB itself seems fine, oddly enough,
but anywhere that the acid hit metal (RFI shields, switches) it
blossomed with massive rust (ok, corrosion, oxidation, what have you).
Does anyone have any advice for a special method to try and clean off
the board? I know there are things that you can immerse/saturate
circuit boards in to remove contaminants but I wasn't sure where
exactly to start. Plus, I'm not even sure if it's worth the time if it
turns out to not work after all my best efforts.
It's the first time I've seen one of these type batteries explode, I
believe it's an N-Type 3.6v, it must have been dead beyond dead. But
all the damage was hidden underneath another part. It seems strange to
me that the board, caps and resistors in the 'blast radius' look
relatively unscathed other than bubbles and flakes of metal from the
nearby shielding.
--
Author: vartan
INET: [EMAIL PROTECTED]
Fat City Hosting, San Diego, California -- http://www.fatcity.com
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vartan wrote:
I have a board which had a lithium battery
explode unseen and was not noticed until we attempted to power it on
(quite some time later, possibly a year or more...). The PCB itself
seems fine, oddly enough, but anywhere that the acid hit metal (RFI
shields, switches) it blossomed with massive rust (ok, corrosion,
oxidation, what have you).
Does anyone have any advice for a special method to try and clean off
the board? I know there are things that you can immerse/saturate
circuit boards in to remove contaminants but I wasn't sure where
exactly to start. Plus, I'm not even sure if it's worth the time if it
turns out to not work after all my best efforts.
It's the first time I've seen one of these type batteries explode, I
believe it's an N-Type 3.6v, it must have been dead beyond dead. But
all the damage was hidden underneath another part. It seems strange to
me that the board, caps and resistors in the 'blast radius' look
relatively unscathed other than bubbles and flakes of metal from the
nearby shielding.
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