On Tue, 24 May 2011 22:36:26 -0700, Jeff Liebermann wrote:

Start by using an ohms-guesser on the charger base. Cut the cord. Is
there DC continuity between the two wires and the contacts on the
charger base? If there's a measurable resistance, then the charger
base has either a resistor, or complexicated charge controller in the
base.

The + side measures 3 ohms.

I would therefore guess(tm) that the wall wart is just a simple
wall wart with nothing more complex than a thermal fuse inside.
However, if there is DC continuity between the leads and the battery
terminal connections, then the charge controller is inside the wall
wart, and a simple replacement isn't going to work.

Since the power supply is obviously blown and useless, tearing it
apart should reveal if there's anything inside. You'll probably find
a thermal fuse. If it's blown, just replace it with a similar thermal
fuse, glue the case back together, and continue charging. However, if
there's a series resistor inside (which is what I suspect), then use
the 12V adapter, add a similar resistor in series, measure the
charging current, and see if it's reasonable 0.1C. If not, adjust the
resistor value for 0.1C charging current.

My guess(tm) is you should have a mess of AA size
NiCd batteries inside the drill, which are usually rated at 750ma-hr.
Using the 0.1C rule, that would be a charging current of about 75ma
max.

It's evidently all original: charger is 92950, power pack is 92955,
and is a *sealed* unit. I see no way to take it apart.

Am I missing something here?

Most chargers and charging bases are solvent welded together. They
can usually be cracked open with brute force. Place a masons chisel
along the glue line, and beat on it with a hammer. The glue line
should crack as the plastic bends. If not, just use a hack saw to saw
along the glue line. Do the repair, and then glue the case back
together.

Thanks for this opportunity for taking revenge on the offending WW. :-)

After freezing, it cracked open easily, but I see no fuse.
Apologies for lack of quality of pix:

http://imageshack.us/photo/my-images...wallwart1.jpg/
http://imageshack.us/photo/my-images...wallwart2.jpg/

Thanks,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."