We've begun hearing reports of malfunctioning BlackBerry Bolds, with the handsets apparently overheating while charging. Though initial accounts are limited to only a few dozen units, the Japanese company selling the affected units, wireless giant NTT DoCoMo, has decided to halt all sales until it gets to the bottom of the problem.

Before you get too worried about an exploding battery and start carrying your BlackBerry in a blast-proof case, calm down, because RIM has checked out its batteries and is confident that nothing is wrong with them. Whatever's getting so hot is coming from the phone itself, not a runaway electrochemical reaction in one of the rechargeable cells. Of course, that in and of itself is a problem for the batteries, as they're not designed for operation when exposed to excessive heat.

As far as anyone can tell, these failures are limited to phones sold in Japan, but without knowing yet just what's going wrong and what phone components are to blame, it's hard to eliminate the possibility of Bolds in other markets suffering the same fate. One culprit could be the phone's cellular radio, a custom part tailored to operate on the specific frequencies used by the island nation. That at least would explain why things seem to be confined to Japan thus far. For now, at least, DoCoMo is playing it safe and waiting to solve the mystery before resuming sales. RIM says both companies hope to get the Bold back on the market as soon as possible.

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