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From: tomm@voodoo.UUCP (Tom Mackey)
Newsgroups: comp.sys.handhelds
Subject: Re: New life for NiCd (was Where can I get a battery pack for my TI-59?)
Message-ID: <989@voodoo.UUCP>
Date: 18 Feb 91 20:49:53 GMT
References: <1101@sppy00.UUCP> <1437@tau.sm.luth.se> <839@DIALix.oz.au>
Organization: BoGART To You Buddy, Bellevue, WA
Lines: 66

In article <839@DIALix.oz.au> bernie@DIALix.oz.au (Bernd Felsche) writes:

[chapter 1 deleted]

>CHAPTER 2 :-)

[portions of chapter 2 deleted, too]

>The tough bit is removing the stainless (?) steel contacts from 
>the cells which have been spot welded to the cells.  A pair of 
>pliers and a twisting motion on the weld should crack the contact 
>strips off.  (welds are weakest in shear)

>You only really need the two contacts from the end cells, which form
>the pads on the top of the battery pack.  Other connections can be
>made with any thin, flat connection.

I tried to reuse the pads for the first pack I rebuilt... I never did
get the pads re-soldered, so discarded them completely in favor of the
following hack:

Use fine wire (I like the individual wires in 4/8/etc. telephone
cables) and solder the batteries together as mentioned by Bernd.

Then just solder two additional pieces of wire to the end battery
contacts and solder the wires directly to the contacts inside the
calculator (make it fast, do it with a steady hand, and apply as
little heat as possible).  Try to solder to a portion of the
contacts that was not used to make contact with the original
battery pack, just in cast you ever find a good one.

As an improvement on that scheme, solder wires to the calculator
contacts as before, but solder them to the wires coming off the
new battery package, so if you have to change them out, you don't
have to probe the calculator innards with a soldering iron again!

With this plan, you can even use non-rechargable batteries in a pinch.
Just don't try to recharge them.  I do this for an old calculator
that one of my daughters is fond of, but for which we don't have
a recharger.

>>>>> wear safety glasses or goggles when soldering batteries! <<<<<<

>When you're happy with the state of charge, re-assemble the battery
>pack.  It can be glued with urethane, solvent plastic cement, or
>similar.

Another thing that works is the strapping tape (heavy duty super
sticky transparent tape with embedded filiments of nylon).  Just
be careful not to put it somewhere where the extra thickness makes
it impossible to fit the pack back in.

I now have a half dozen or so calculators (including a TI59, but
mostly HP's) that are now productive again owing to my battery
transplant surgery.

>-- 
> ________Bernd_Felsche__________bernie@DIALix.oz.au_____________
>[ Phone: +61 9 419 2297		19 Coleman Road			]
>[ TZ:	 UTC-8			Calista, Western Australia 6167	]


-- 
Tom Mackey       (206) 865-6575        tomm@voodoo.boeing.com
Boeing Computer Services         ....uunet!bcstec!voodoo!tomm
M/S 7K-20,     P.O. Box 24346,     Seattle, WA     98124-0346