Repairing Blackberry dropped in water - circuit board cleaning?
Hi,
My friend wrote me this problem, didn’t know what to do. This is what he says…
I did a lot of electronics in the high school days (even getting 99% in Electronics class) but that was many years ago.
I’ve got a Blackberry 7280 (a cellphone with very good email) which got exposed to water by being dropped in a puddle. The battery was removed immediately (avoid short circuits) and the Blackberry was disassembled to dry out. Reassembled after something like 24 hours.
I now need advice on circuit board cleaning.
The good news is the Blackberry pretty much works fine with one exception (its computer is fine; I can connect to the Blackberry phone over USB; and the screen is working fine). But the thumb keyboard is malfunctioning. It’s as if two or three keys are stuck down, or a matrix wire is shorted. Definitely, at least the “S” key is stuck down because I know it tries to execute a (S)earch upon turning on. I can override it by holding down a key while booting up the Blackberry by putting the battery in (any of the leftmost 5 keys of the first row, or the letter ‘a’ in the second row). That allows me to give limited one-keypress control of the Blackberry, but then the stuck key(s) take over.
I disassembled the Blackberry again and scrubbed as much residue I could out of the contacts. I removed the keyboard down to the bare contacts, used pencil eraser, used isopropyl-dipped Q-tips, used water, cleaned the keyboard contacts. But I booted up the Blackberry without the keyboard buttons (just the circuit board contacts where the keys were) and the “S” key is still stuck down, so it is obviously that the short must be somewhere much further upstream. (Just to be sure the behaviour was the same as having the keyboard buttons on it, I covered the “Q” contacts with a piece of metal, and was able to simulate the “Q” keypress if I shorted it while applying power to the Blackberry).
I spent over an hour of time using isopropyl-dipped Q-tips scrubbing any residue I could see, including some that I saw between surfacemount components.
Reassembled. Still no dice. Something still seems shorted somewhere.
Looks like I have to try something more drastic, such as immersing the circuit board completely inside a circuit board cleaning liquid, in an attempt to dissolve any residue that might be hiding underneath the pesky BGA chips or between ultra-high-density chip pins. There gotta be residue hiding underneath an inaccessible area.
It’s a 2003-era circuit board design, highly integrated with lots of surfacemount components and several tiny BGA-like packaged chips, as well as others (not sure what kind of packaging, MQFP, or whatever — I’m very rusty on my terms)
I need to now attempt to dissolve residue that may be hiding in places such as between BGA contacts underneath chips. Will brief 1 minute immersion & washing in 90-97% isopropyl liquid be safe? Distilled water? Or what liquid would be the best? Or too dangerous? I can remove the LCD screen and put the LCD screen aside.
At this moment, I’m willing to be almost sort of kamikaze on this circuit board since my last resort is to fork out for a Blackberry replacement ($400). So I need to do some reasonably inexpensive last-ditch attempt, such as washing the circuit board in a recommended liquid. Is 90-97% isopropyl fine? Or what inexpensive chemical? At what percentage? Keep in mind, I can only use chemicals safe enough to use in a condo and meets Canada regulations (I’ll check).
Thanks,
Mark Rejhon
help
Mike Harrison said,
July 28, 2007 @ 9:50 pm
I’d suggest distilled water, then maybe an alcohol solution. Ideally in an ultrasonic cleaner.
Rinsing with the aid of a compressed air jet may also help dislodge contamination.
Michael said,
July 28, 2007 @ 9:52 pm
Allowing the unit to sit for a time while wet is *not* good. Gives
contaminants time to corrode what it will, also to migrate. Immediate
disassembly and flushing is best. And don’t stop the work until all of
it is done. Distilled/deionized water is good, but keep it away from
coils, transformers, and the like. Unpotted SMT (for example) can give
hiding places for contaminated liquid; flush well and use compressed air
to get every last droplet out.
You could have a dried, conductive droplet straddling two or more etched
lands. If the short lies beneath a component - likely, since liquid
likes to “wet” itself in, under, and around objects - then you could be
in for a long troubleshooting session. Been there; done that.
By the way, the most destructive “spill” I personally had to deal with
was coffee in the keyboard of a laptop. I didn’t get the keyboard
opened up until about 18 hours after the spill, and by then I had a
bunch of hopelessly corroded key contacts. Putting off disassembly
until next day wound up costing me nearly $200.
Mark Rejhon said,
July 28, 2007 @ 9:52 pm
Hi,
I’m familiar with the need to remove the battery and disassemble as
immediately as possible.
Is there a chemical I can add to distilled water that reduces its
surface tension, while being non-conductive? Obviously, if I want to
clean in the gaps between pins and underneath chips, I need minimum
surface tension. I figure that I need a viscious circuit-board-safe
liquid that can wet more deeply than the original accident, to
maximize my chances of success. Some people say adding a percentage
of mineral or methylated spirit to the water, really helps in cleaning
circuit boards. What is your opinion? Was recommended to
vibrate/swish the circuit board in some recommended circuit-board-safe
liquid, in an attempt to clean those pesky areas.
The Blackberry circuit board looks in excellent condition, and I can
keep the LCD screen separate. There are no coils and transformers on
this particular board.
Recommendations?
Thanks,
Mark Rejhon
Jim Thompson said,
July 28, 2007 @ 9:53 pm
Clean it with *denatured* alcohol. Denatured alcohol will combine
with water to form another alcohol that remains volatile and will
evaporate. Commonly used to dry artificial fishing flies. Available
in most hardware or paint stores.
…Jim Thompson
Mark Rejhon said,
July 28, 2007 @ 9:54 pm
Hi,
I have heard a few recommendations of Isopropyl alcohol
(at least 90% pure versions), but have never heard of
a recommendation of denatured alcohol.
Is denatured alcohol a better circuit-board cleaning fluid
than 90%+ pure isopropyl alcohol?
Can you give me any references as to denatured alcohol’s
usage in circuit board cleaning?
Thanks!
Mark Rejhon
Jim Thompson said,
July 28, 2007 @ 9:54 pm
Commonly available isopropyl alcohol is likely to have some oil in it
and will leave a residue.
I don’t have any denatured alcohol references, I just keep a quart
handy.
I’m not recommending a long soak… just dip and remove and let
air-dry. All the moisture will be gone, which is likely the problem.
My wife dropped her phone in a foot bath. After I got it dried out it
came right back to life.
…Jim Thompson
Michael said,
July 28, 2007 @ 9:55 pm
Yup. One “commonly available isopropyl alcohol” - found at any drug
store - is marked “rubbing alcohol”, is used for rubbing a person’s
body. This stuff does have some kind of oil additive. The oil helps
hand/fingers slide over skin without pulling it. Like Jim points out,
the oil will be left behind after the alcohol evaporates, and you do not
want that stuff all over your electronics. I have seen rubbing alcohol
used to clean heads of tape decks too. Also a bad idea.
Mark Rejhon said,
July 28, 2007 @ 9:56 pm
Actually I’d hunt down chemist grade 90-97% isopropyl. That would
obviously have no such oil in it.
I’m really interested in how it compares to simple HomeDepot-bought
denatured alcohol.
Which of the two is better? A trip to Home Depot is probably very
easy to do, but I would want to know some references to successes with
denatured alcohol…
I believe I need longer immersion, since I’ve already Q-tip-washed the
circuit board to no effect, so a deeper clean is needed — to get into
little nooks and crannies that couldn’t be reached. Like between
balls under BGA chips, and between pins of other surface-mount chips.
At the very least, a few minutes swishing in distilled water, but I
also need something else that reduces the surface tension of water
without leaving behind conductive residue, and helps in dissolving.
One guy recommended 15 minute immersion, but we’ll see. So the
liquid needs to be benign enough for such an immersion.
So far, candidate additives to distilled water include:
* isopropyl alcohol (chemist grade, not drugstore, 90% or better); or
* denatured alcohol; or
* methylated spirit
It’s also recommended from a few sources that certain industrial-grade
detergents are recommended, but these would seem to be hard to find.
I’ll be making the final decision this weekend based on consensus…
Mark Rejhon
Jim Thompson said,
July 28, 2007 @ 9:56 pm
I’m certainly no chemist (and I’ll ask my daughter who is) but I
believe that denatured alcohol is simply alcohol that has had all the
bonded water molecules excised (I’m strictly winging it here from
chemistry studied more than 40 years ago… “water of hydration” ??).
Thus it has a strong affinity for water.
The best part of it is that it will bond to some water but still have
a high vapor pressure.
…Jim Thompson
jtech said,
July 28, 2007 @ 9:56 pm
I have used denatured alcohol to clean pc boards, it dries quickly and
leaves no residue. Don’t use water as the oxygen content will bond with any
metal parts and start the rust to start forming, even if you feel it is dry.
The denatured alcohol will absurb the water molecules that is stuck to the
parts. Dip it about 10 sec and let dry overnight before re-assembly.
Good luck!
Jim Thompson said,
July 28, 2007 @ 9:57 pm
Thanks for the second to my motion! Denatured alcohol is neat stuff!
…Jim Thompson
jtech said,
July 28, 2007 @ 9:58 pm
np. btw, my name is also jim thompson - James T. Thompson.
Jim Thompson said,
July 28, 2007 @ 9:58 pm
Way too many of them in the world…
My grandfather’s name was James L.
His grandfather’s name was just James
My father’s name is James R.
My name is James E.
So I’m named my sons Aaron and Duane
…Jim Thompson
Zak said,
July 28, 2007 @ 9:58 pm
“Denatured” here means that some methanol was added to the ethanol to
make the stuff poisonous and thus unfit for consumption.
Acetone is sometimes added intead. Acetone works very well in the lab
for drying glassware, but it is too strong a solvent I guess.
Alcohol in the 96% concentration will take water with it when it evaporates.
Thomas
Jim Thompson said,
July 28, 2007 @ 9:59 pm
You’re confusing “denatured” in the legal (beverage) sense with a
specialty product called denatured alcohol…
======================================
Definitions:
Denatured Alcohol is ethyl alcohol, or ethanol, containing traces of
benzene. While ethanol, in it’s natural form, is a source of
combustible fuel, it contains trace amounts of water making it less
efficient for burning than in it’s denatured form. Introducing Benzene
during the distillation process drives out the water contained in
ethanol creating a very pure and potent fuel source - denatured
alcohol.
NOTE: Ethanol is the alcohol consumed in alcoholic beverages. However,
once denatured, ethanol becomes toxic and can cause blindness or death
if consumed.
Rubbing Alcohol is isopropanol. It has a completely different
molecular structure than ethanol and often contains up to 30% water.
Though it is flammable it is a poor choice for fuel.
======================================
The above definitions are written for Joe Average, the alcohol doesn’t
“contain” water, there are instead *bonded* waters-of-hydration.
…Jim Thompson
Jim Thompson said,
July 28, 2007 @ 10:00 pm
Probably! ROFL!
…Jim Thompson
Mark Rejhon said,
July 28, 2007 @ 10:03 pm
Hi,
My Blackberry works now!
The good news is that a 10 minute immersion in distilled water
(drugstore variety distilled water), including shaking, swishing, and
jiggling, then quick drying with paper towels, followed immediately by
a 2 hours in my oven preheated to about 150 degrees F (oven turned off
and temperature before Blackberry inserted in oven) even before I
removed the Blackberry from the water, to minimize oxygen exposure to
a wet electronic circuit board. To maintain heat, I intermittently
turned on the oven for 10 seconds while my hand was inside the oven as
a control to make sure it was never too hot to keep my hand in the
oven. I did not use any denatured alcohol or 97% isopropyl alcohol
– although that would have been my next step (I had a difficult time
finding denatured alcohol, which affected my decision to try just
distilled water first.) Although it is true there is oxygen content
in the distilled water, I am told it is supposed to not be nearly as
corrosive as as other types of water (like tap water) and keeping it
underwater in relatively cool much purer water for only 10 minutes
probably won’t do more damage than the damage already done in the
first place by the contaminants of dropping into a dirty puddle that
got it broken in the first place..
I was going to wait 24 hours, but the blackberry seemed fully dry
after 10 minutes, so I continued. After about 3 hours, I reassembled
the Blackberry cellphone and it WORKED!
So now I’m a happy camper. There is a minor stain in the backlighting
(I removed the LCD and the thumb keyboard and put them aside before
immersing the circuit board in the water), and the thumb keyboard
seems a little well-used, but that’s mostly it. I have activated the
Blackberry now.
Thanks to all the people who gave me advice, which almost always
mentioned distilled water as a washing step, usually alongside another
agent as a rinsing step (i.e. denatured alcohol). Except for a couple
of advice.
So next time, if something is possibly not worth repairing through any
other means, and the defect is a short circuit somewhere (i.e. stuck
buttons), then a distilled water bath followed by low-temperature oven
is the ideal route that avoids permanent banishment to a junk
drawer….! For me at least.
I’ll probably try denatured alcohol, if I could easily find some
locally — may have to go further to a big place such as a Home Depot
somewhere in the suburbs.
Mark Rejhon
Jim Thompson said,
July 28, 2007 @ 10:03 pm
Home Depot, Ace Hardware, Lowes, just about any national chain carries
denatured alcohol in their paint department… I think its common use
is to thin shellac.
…Jim Thompson
Edwin Irizarry said,
August 12, 2007 @ 5:12 am
Hey guys this was a very interesting forum. If I can call it like that, I got a Samsung I730 that I loved to use until one day where the touchscreen functionality ceased to work. Frustrating since this phone is not cheap enough. Touchscreen wiring looks intact, some corrosion on the contacts and I’m not exactly sure what this phone has gone through before me since I got it on Ebay. So most prolly I rendered this problem to the circuit board. Is the dipping the way to go? If so, Denatured alcohol should be the best option or simply try distilled water first like our buddy over here. Thanx in advance for the advice.
Nigerian Scam Baiter said,
August 14, 2007 @ 3:28 pm
Hmm, from my experience with an MP3 player, I say denatured alcohol is the best solution, not sure what water alone would do. If there’s corrosion on the contacts clean it off.
Blackberry Fixer said,
January 12, 2008 @ 5:40 am
I had a similar problem, the blackberry (8300) was dropped in water and the keys stopped responding. I took it apart, removed the motherboard, poured SKYY vodka into a bowl and submerged the motherboard for about a minute. Then I put it in the oven at 200F for about 30 minutes. Reassembled the phone and everything worked like magic. Good luck.