A couple days ago my cell phone experienced a very relaxing trip into the jacuzzi. After drying it out, it still works. Almost. The part that broke seems to be the sensor that detects if the lid is closed or open. The sensor is somehow based on sensing the proximity of a magnet in the lid, and without it the LCD doesn’t turn on except momentarily as I’m opening the phone or when swiping a magnet across the base.
Any idea how to fix it?
If I tried to wash the phone (eg maybe it’s chlorine residue), should I use filtered water, bottled water, or 91% isopropyl?
If it works as you describe, it’s probably a little Hall-effect sensor. Assuming the hot water didn’t dissolve the adhesive which presumably holds the magnet in place allowing it to dislocate, there’s little else that can go wrong, other than an unintended circuit path someplace. The best thing to rinse it with to remove residues is 100% isopropyl, but your 91% should do in a pinch. Dunk it in, swish it about thoroughly, shake out as much of the excess liquid as you can and let the phone dry out someplace warm (but not TOO warm).
So you think the isopropyl won’t dissolve anything important? I realize it’s not acetone, but there’s more than a circuitboard inside the phone. Also, I have one of those small ultrasonic baths. But again… might it be too much of a good thing?
The devices themselves are immune to those things; the PCB pads and circuit traces necessarily connected to them are not. Water can easily get under SMDs and once there is hard to get rid of, because the tiny gap between the device and the board exerts a great deal of capillary action and the small exposed surface area means drying time at ambient temps and humidity is looooong. Iso is your best bet. I’ve never had it dissolve anything important; I use it to aggressively clean flux from all sorts of boards after soldering. I wouldn’t use the ultrasonic cleaner.
Yeah, it cleans flux great, but like I said, PCBs haven’t got glue, plastic shells, or other components of a phone. I’m thinking there’s nothing but glue holding the plastic screen on. That wouldn’t be so bad. I just hope the mic/speaker doesn’t use glue for anything important.
Anyway, I’ll give it a shot. First, without the ultrasonic.
Iso seems fairly benign to most adhesives that I’ve come across. I’ve tried to use it, for example, to clean label residue off various items and it only makes a sticky mess. And I have yet to encounter a plastic it will dissolve, even partially. Probably why it was the electronics industry standard cleaner, at least until the EPA got all pissy about it.
I fixed it!
I figured out how to take it apart (tricky little bastard), took out the PCB, left it in the ultrasonic isopropyl for a good 15 minutes, dried it out well, and now it works. The screen, though, shows some very faint brightness splotches since the first time I dunked it in alcohol, so I’m still not sure putting the whole phone in was a good idea.
So I’d left the isopropyl in the small ultrasonic bath for a couple days. I come back today. The alcohol apparently had been evaporating and condensing on the lid, then dripping back down, in a continous cycle. Although the bowl of the bath is metal, the lid is made of some sort of clear plastic. A clear plastic that dissolves in isopropyl. I came back today to find the back filled with a gooey substance and the lid almost glued shut by the same goo.
What? That’s nonsense, unless you want me to send you a sample to find out the type of plastic. It’s my fault for not cleaning up after myself anyway. Still, it’s something to know that isopropyl isn’t totally benign.