On Mon, 23 May 2011 20:24:18 -0400, "Wild_Bill" wrote:

The reply from whit is a good suggestion, but I suspect that the cells in
the drill are shorted, which will damage a charging power supply. It seems
that the old supply became overheated and failed, which will happen if the
cells are shorted.
I believe this is the reason for the substitute wall wart getting hot.

Certainly possible, for all I know.

I shoulda mentioned, I'm not an electronics guy, just a tinker. Limited
(make that -very- limited) skills, eqpt.

I might've charged with the new supply 20 min. before I noticed the heat.
The drill worked a little thereafter.

To find out if the cells are shorted, the cells need to be accessed, and
individually checked with an ohm meter or an instrument capable of measuring
battery cell impedance or ESR.
Also, a reading for individual cells with voltmeter reading of zero volts
generally indicates shorted cells.

The drill still works a little. I measure about 4v aggregate from the
battery pack.

Replacing all of the cells is the most effective solution, and cells with
tabs can be soldered together in the original order, and restore full (or
even better) operation of the drill (or most cordless tools).

The usual case, not practical. Wierd cell shapes, very old unit.

If you have the ability to make good solder connections, replacement is
usually less costly than paying someone else to do the work.

There are numerous online sellers with reasonable prices for replacement
cells.

If I can't tinker-fix it, it goes in the trash. Any replacement parts
either won't fit or are too expensive or both. I hate to throw
potentially useful tools away, but ...

Thanks,
P

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