TI-58 Slimline


I never liked the bulky shape of the TI-58/9. It was necessary for the 59's card reader but not for the 58. Opening it up shows a lot of empty space. So why not cut it out?

A kind forum member sent me some disused case backs and I applied a Dremel cutter and some wet sandpaper. I added a new clear bottom and a cell phone battery. It needs finishing, such as black paint around the edges. It's now only as thick as a TI-84 and I hope to use it as a daily driver, if the battery life allows.


Another example of a geek with too much time on his hands. [:-)

Where were you 30 years ago?


30 years ago I was programming my 2nd personal computer, a TI-59 (couldn't afford an HP). 1st was a TI SR-56, 3rd was an Atari 400 (couldn't afford an Apple II).

Besides, where were Lithium ion batteries 30 years ago?

Edited: 26 June 2010, 10:13 a.m. after one or more responses were posted


Very nice, I love it also. Keep us informed about battery life.


30 years ago I was programming my 2nd personal computer, a TI-59 (couldn't afford an HP).

I was programming a TI-59 myself, my first calculator/computer. A slimmer TI might have appealed to me back then...

I love it! Very nice work.

Edited: 25 June 2010, 9:42 p.m.


Since it won't hold itself at an angle anymore, now all you need is one of those neat angled desk calculator holders EduCalc used to sell!


Finally, the back is finished.


Pretty neat!!!! Congratulations!

Luiz (Brazil)



Nice job indeed. One tech question: Is the Li-Ion battery charger included into the calculator body or is the battery charged by a separate charger/device?

Cheers from Spain.



I use a broken cell phone to charge the battery. But yours is an interesting idea, if I can remove the charging circuit from the phone or find a small charger. Hmm, I thought I was done with this project!


I wonder if that's possible with the 48G housing.


The 3.7 V Li Ion battery does 850 mAh, which matches nicely the voltage and capacity of the old 3-cell NiCd packs from HP and TI. I don't know about the 48G, though.

In use, the battery does not get as warm to the touch as the 58's DC-DC converter.


Very nicely done!!!!!

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