From: Calvin Grier (cgrier_at_ix.netcom.com)
Date: Thu Oct 21 2004 - 06:45:39 PDT
This is a good tip, Joel. The "alkaline" battery trays are very good things
to have and use.
Did you by any chance re-build any of the rechargeable battery packs? This
is the first re-charge failure I've heard of - but I completely agree that
capacitors tend to give-out after many years of use. (Just ask any TV repair
technician.)
----- Original Message -----
From: "Joel M. Sciamma" <joel_at_inventors-emporium.co.uk>
To: "NewtonTalk" <newtontalk_at_newtontalk.net>
Sent: Wednesday, October 20, 2004 7:29 PM
Subject: [NTLK] Moving away from MP2K internal charging
> I would like to suggest something that I think might be a safer solution
to
> powering the MP2K models as they get older.
>
> I have now seen three machines which have been terminally damaged due to a
> failed capacitor in the charging circuit/power supply while charging the
> original NiMH battery pack with the Apple mains adaptors. When this
> component fails, it tends to do so with some energy and leaves a bit of
mess
> on the PCB.
>
> As the MP2K components get older, this kind of failure mode is to be
> expected when high currents have to be switched in an environment of
> elevated temperatures, both in the parts themselves and the battery pack
at
> end of charge.
>
> As a consequence, I have stopped using the Apple NiMH battery packs (which
> were getting to the end of their lives anyway) and instead I'm using NiMH
AA
> cells in the battery tray, charging them externally as alternating sets of
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