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

Shares of ATT and APPL dropped as fewer people picked up on the iPhone as expected. However, with Holiday season coming up before you know it and back to school people will be picking up on the iPhone as well as professionals picking up the Blackberry Curve.

http://www.contracostatimes.com/technology/ci_6451578?nclick_check=1

Its a 2-for-1 on ATT being nearly an exclusive carrier to both phones.

The latest blackberry curve 8300 just released to the Jamaican market through the local carrier, Digicel.

With blackberries, there is optimal organization and time effectiveness on a day-to-day basis making blackberries the preferred smart phone within corporate Jamaica (Thursday Life Tech).

The blackberry is still slick and widely used, however the Curve is not an alternative to the pearl but a completely different phone. Its the lightest, smallest blackberry to come with a full QWERTY keyboard unlike many of the others using SureType technology. The Curve has styled liquid silver finish, soft edges and clean lines.

The new Blackberry Curve has all the typical features and more. 2.0-megapixel camera, expandable memory, voice dialing, multi-media player, and more.