TI-58C not powering up

[Andrew Varney]

I have recently dug out my previously (40 years' ago!) much loved TI-58C calculator. I used it a lot in my school days, then got a replacement battery in 1989 but after that it was put in storage for 30 years. When I plug the power adaptor in, the calculator does not even display. As I remember, it used to be able to run on the power supply even when the battery was flat. Not sure if the reason is that the battery is beyond /just/ flat after 30 years in storage, if the power supply adaptor is not working (I've checked fuse, but don't have another calculator to check it on), or if there is some other reason.

Has anybody else experienced something similar and/or can suggest further checks and how I can make them?

[Maximilian Hohmann]

Hello!

If the battery is totally dead it can absorb all the power that it gets from the charger with nothing left to power the calculator.

This series of calculators from Ti can safely be powered from their charger without a battery in place (other than the notoriuos "Woodstocks" from HP). It may not be working properly because the battery is required to stabilise the voltage, but at least you should see the display coming on and get some response from the keyboard.

The safest option would be to remove the battery and connect the contact srprings to a regulated (laboratory) power supply using crocodile clips. Set the voltage to 3.6V DC and mind the polarity. Which is not difficult because contrary to HP - and I say this to our members here who enjoy bashing Ti :-) - Texas Instruments undertook the effort to put polarity labels next to the battery connectors!

Replaycing the charger is not so easy. There are quite a few different ones depending of the year of manufacture of the calculator (Datamath has the full list here: http://www.datamath.org/AC_List.htm) but they all have in common that they output AC voltage and have a proprietary plug to connect with the calculator. So if indeed your charger is broken, forum classifieds and eBay will be the places to look for a replacement. By the way: The ones that came with the calculators originally in Europe (I have several and they are all identical) are completely sealed and have no fuse. They either work or have a burned out transformer.

Good luck with your repair, it's a pretty calculator well worth being brought back to life again!

Max

NB: If your calculator still works it might be an option to replace the NiCd cells with more modern Lithium cells as described in this Hackaday article: https://hackaday.io/project/176529-ti-59...ttery-pack

[Massimo Gnerucci]

(04-07-2022 11:45 AM)Maximilian Hohmann Wrote:  Set the voltage to 3.6V DC and mind the polarity. Which is not difficult because contrary to HP - and I say this to our members here who enjoy bashing Ti :-) - Texas Instruments undertook the effort to put polarity labels next to the battery connectors!

Like this, you mean? ;-)



Note the markings on the inner posts.

[Maximilian Hohmann]

(04-07-2022 01:55 PM)Massimo Gnerucci Wrote:  Like this, you mean? ;-)

The one exception that proves the rule :-)

[Dave Britten]

On a related note, I wish Mark Hoskins would make a TI-59/58 version of his excellent HP Classic AAA battery packs! I whipped up one myself for my 59, and it works fine, but it's definitely not as refined looking.

[Maximilian Hohmann]

(04-07-2022 02:58 PM)Dave Britten Wrote:  On a related note, I wish Mark Hoskins would make a TI-59/58 version of his excellent HP Classic AAA battery packs!

He does! Visit eBay item number 324472479653

[Dave Britten]

(04-07-2022 03:35 PM)Maximilian Hohmann Wrote:  

(04-07-2022 02:58 PM)Dave Britten Wrote:  On a related note, I wish Mark Hoskins would make a TI-59/58 version of his excellent HP Classic AAA battery packs!

He does! Visit eBay item number 324472479653

Oh cool, that looks like a good option. Personally I like the ones that just use AAAs (usually Eneloops) that you can pop in and out. I can keep a standby set, and charge them with a good NiMH smart charger.

[Maximilian Hohmann]

(04-07-2022 03:45 PM)Dave Britten Wrote:  Personally I like the ones that just use AAAs (usually Eneloops) that you can pop in and out. I can keep a standby set, and charge them with a good NiMH smart charger.

I also have one of these for my HP classics. An excellent product indeed. But I don't think this principle can easily be adapted to Ti battery packs, because they are closed on all sides.

[Dave Britten]

(04-07-2022 04:09 PM)Maximilian Hohmann Wrote:  

(04-07-2022 03:45 PM)Dave Britten Wrote:  Personally I like the ones that just use AAAs (usually Eneloops) that you can pop in and out. I can keep a standby set, and charge them with a good NiMH smart charger.

I also have one of these for my HP classics. An excellent product indeed. But I don't think this principle can easily be adapted to Ti battery packs, because they are closed on all sides.

True. The way I did it was to build a AAA battery pack that was very similar to the HP versions (with different contact placement and foam shape), then take an old dead TI battery pack and cut off everything with my Dremel so that it was nothing but a flat door for the battery compartment. Works like a charm, and you'd never notice the difference looking at the outside.

[DrewNicholson]

Aloha,

If a person happens to have a PC-100x printer, I am finding that calcs that don't seem to want to work on the power cord *do* wake up on the printer. My old SR-52 came to life with some wiggling, and then a TI-59 was working. Neither was working at all with the power cords.

I haven't rebuilt any TI battery packs yet.

Mahalo

[Xorand]

I have both a 58C and a 59 along with 3 or 4 battery packs I rebuilt for them with modern NiCad batteries. The 58C, in particular, seems to be picky on how the battery pack is inserted even though the spring terminals are in good shape. Seems I have to reinsert the pack several times to get it to make contact well, then it is good until literally the next time I turn it on.

Not sure if a dead battery pack in the calculator would prevent a working power supply from powering up the calculator. Taking it out and trying again certainly wouldn't hurt to try. Is there any blue-green corrosion on the calculator board from the battery pack? Might be some corroded traces if so.

The correct adapter would be the 9131, which puts out 3.3V AC. If you have a test meter, you could test the voltage output of the power pack. You would need some thin wire to stick in the tiny holes of the connector, though.

[Steve Simpkin]

(04-07-2022 11:45 AM)Maximilian Hohmann Wrote:  ...
The safest option would be to remove the battery and connect the contact srprings to a regulated (laboratory) power supply using crocodile clips. Set the voltage to 3.6V DC and mind the polarity. Which is not difficult because contrary to HP - and I say this to our members here who enjoy bashing Ti :-) - Texas Instruments undertook the effort to put polarity labels next to the battery connectors!
...
Max

The lack of labeling or even documenting something as simple as the battery polarity by HP reminds me of the battle Dr. William Kahan had with HP management about adding additional explanation chapters for the Solve and Integrate functions in the HP-34C manual.

"That’s how the HP-34C was born. They agreed to do it, and then like a thunderclap, they were appalled when I said, “You know, we’re going to have to put some guidance into the manual because people who use these keys, especially the integrate key, they can fool themselves. These things cannot be foolproof. There will be situations where people will get misleading answers, and they need a little bit of guidance about that.” “Kahan, you just told us to do this stuff, and now you tell us that you’re going to get wrong answers! I mean, all this time, we’ve been listening to you tell us how to get the right answer, invariably, every time!” Well, the difficulty was then that I’d have to go to the manual writers. But there was a Hewlett-Packard policy which said, “We are professionals, and we sell to professionals. We tell them what the device does, and they figure out how to use it. We’re not writing tutorial material in our manuals.” And I tried to explain, “Look—this time you’ve got to put some tutorial material in the manuals. You really must. Otherwise, folks are going to fool themselves.”

Well, the managers wouldn’t do it, but I had persuaded Barkin, and I can’t remember the name of the other guy. It’s probably in there somewhere. There were two guys who were writing the manuals, and I persuaded them. I think persuasion is the wrong word. This was a case of subversion. I subverted them and got them to do something that their managers had told them not to do. The manual writers listened to my arguments and decided that I was right, and their managers were wrong. And that’s a dangerous decision, you know. You can get fired for that. They wrote the two extra chapters into the manual, which said something about the solve key and something about the integrate key, and a little bit to warn you. And I had written up some more stuff, which ultimately got into the Hewlett-Packard Journal. And the managers were outraged."

Dr. William Kahan Oral History:
http://history.siam.org/pdfs2/Kahan_final.pdf