My Nokia 6021 died the other day. Of course my wife blamed me for swapping my battery with the nearly dead one in her phone so I could use her camera to take some snaps of a family gathering.
I originally picked up an unlocked Nokia 6021 in particular because it was the only tri-band international GSM phone that supported EDGE & bluetooth, but had no built-in camera so I could take it to work. I wish the american GSM providers would figure out that there's a market for this beyond those blackberry devices. I prefer keeping my PDAs and cell phones separate so I could upgrade them independently, thank you. Plus, I typically get a better overall feature set out of $200 cell phone + a $200 PDA compared to the leading $600 "smartphone" of the time.
So the symptoms of my Nokia mobile's demise was a crash on bootup... I'd hit the power button and the screen would just flash white and then shut off again. Once in a blue moon, I could get the thing to boot up a little past the bootup screen, but it would crash again while building the menu. I could also convince the battery to charge to full, so it wasn't a low battery problem.
I pried the thing open and removed the 6 screws holding it together. Inspecting the circuitboard near the main battery contacts, I noticed a tiny little XH414X battery cell that showed signs of corrosion. Nokia had welded it to its battery contacts, so with nothing to lose (I never bother with warranties, esp. with my ~$200 price cap on most of my personal electronics), I simply twisted it out with a pair of needlenose pliers. Afterwards, the phone booted up and worked fine, and remembered all of my memory settings... everything except for the time!
So this little permanently-attached watch battery is apparently a little time bomb waiting to incapacitate your Nokia phone. I suppose mine died early due to the corrosion... I'd be the first to admit that my children and my pocket provide a pretty rough operating environment for my gear. But it's still a bit unnerving that they expect you to upgrade your phone after however many years that battery would last. But since the phone works with the internal clock battery dead, I'm not sure what to think. It's not much of an inconvenience, and my phone offers to set the time from the network on bootup anyway, so it would only be a problem if my main battery died and got replaced while I was stuck in a cave. Perhaps I just hit a weird failure mode where the corroded battery was feeding back some strange voltage that the Nokia engineers didn't expect from a normally dying watch cell.
Anyway, it has vaguely inconvenienced me for a few days while I was on international travel, but here's hoping someone will find this information useful in debugging their related Nokia phone troubles.