TI 58 Repair
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- čas přidán 22. 08. 2024
- Several months ago I got this calculator from an auction site since I was being nostalgic. Fran's mailbag video • FranLab: Viewer Mail #1 reminded me that I had some video to edit!
Here I repair the battery holder and contact on a TI-58, the younger brother of the TI-58C and the TI-59.
Cool! I Still have a working Ti55 I bought with all the loot I made cutting lawns and taking care of neighbors pets during the summer when I was 15, in 1979. It was programmable sure but has very few program steps and is lacking in instructions compared to the more advanced programmable calculators.
I wanted a HP41C but it was way above my pay grade. I would have settled for a Ti59 or a 58 or even a 57 but again, way more money than I could come up with.
About 10 years ago, I nerded out on EBay and picked up a Ti59 with a broken power pin like the one you repaired with a PC100A printer cradle. I also picked up a Ti58C (constant memory) that I repaired the battery for. It works like a champ. I do love these old calculators.
I just got my TI-58 from an online seller. The PCB in my unit has a slightly different arrangement and some of the components are in different places than in yours (including capacitors and the "trimmed" chip in the corner). Clearly they have changed the design over years.
My unit came with no battery pack at all and there was no indication on the PCB about the polarity of contacts. I learned from your video which is which - thanks!
It was released May 24, 1977, one day before the first Star wars movie came out...
The TI-58 and TI-59 were introduced in 1977. The TI-58C was introduced in 1979 with some internal circuit improvements and that's when I bought my TI-58C. Also bought a printing cradle for it (PC-100A). The "wall wart" it came with is the AC9900/H-sw charger that can switch automatically between 120VAC and 240VAC input, and outputs 6.2V @ 200ma (hence the "sw" appended to its model number; models without the "sw" are 22VAC input only). Has a Euro two-pin plug and requires a simple and cheap two-blade adapter for North America (no need to change voltage). I'm betting it's AC in spite of its polarized plug for the calculator, which could make sense if it has a full-wave bridge rectifier circuit . . . which would chop that approximately in half and provide charging for the ~3VDC battery pack (NiCads are 1.2V). If you replace the batteries and get a wall wart made for it, use *only* NiCad as the charging circuit is *not* made for NiMH. I've got two battery packs, one original and a second bought to replace it when it went dead. I'm going to mod the original to take replaceable AA batteries - likely will still go with NiCads, and will mod the second when its cells eventually die. If you use anything other than NiCads, pull them out before plugging in a wall wart!
Additional Notes:
The US Army was using the TI-59 with the printing cradle on a limited basis to evaluate feasibility in parallel with the M18 FADAC, an ancient solid state field artillery fire direction computer that was fielded in 1960 (FADAC = Field Artillery Automatic Digital Computer). It's not a trivial problem as the trajectory is affected by meteorological conditions including temperature, humidity, air pressure, wind velocity (a vector that includes direction), and precipitation (type and magnitude). The TI-59 fire direction program was fully capable of handling tube (e.g. howitzer) and missile artillery with high precision, and it was faster than the M18 FADAC. the printer was required for record-keeping in the event of an investigation regarding an errant round landing off-target (very serious and extremely thorough). The TI-59 with printer was overtaken by the fielding of TACFIRE. One of the major concerns with the TI-59 was its robustness in a US Army field environment that would subject it to all manner of shock, vibration, dust, moisture, etc. It wasn't hardened for it. Had it been fielded, the contract for it would have requested special hardened models specifically made for those conditions.
Good thing they didn't field it. The memory card contacts were fragile. I doubt that they would have stood up to much abuse. My original from 81 developed a broken finger after 8 years of normal use.
And thanks for the tips on the wall wsrt. I run it off 5v from USB now.
@@grtyvr I have verified the charger is 6.2VAC and you were correct that it's a bridge rectifier on the PCB. TI specifically warns that that calculator must not be operated from the charger alone, that it requires the battery pack as part of the "filtering" of the AC - presumably to smooth the ripple and to provide protection against voltage spikes - which could occur the charger is plugged in or unplugged (particularly from the calculator) while the calculator is on. I presume your 5 volt power supply is well behaved. I've got a pair of battery packs and will be cycling them through getting them rebuilt to allow removing and replacing AA cells in them - gives the option of alkaline, NiCd, or NiMH (the TI charger cannot be used with the NiMH, only NiCd). One pack still works and the other, a dead one, goes in first. As an additional note, if the TI-59 had been fielded, it would have been hardened with a different case and keyboard, and printer likewise hardened. A custom ROM would have been used versus the mag reader so it needn't rely on it. The ROMs are very hardy. The need for a TI-59 was its larger working memory. Don't know how many different ROM libraries you have, but they were one of the great ideas TI had for the 58/59. I used several in addition to the one it came with. Several corporations had custom ROM libraries made by TI for them that contained specialized proprietary programs unique to their business.
Oh that's interesting, the board seem to have been the same as the TI-59, bit it's just not populated with the card reader circuitery. You notice there's a whole area without components on the right of the battery contacts. Also the whole space in the head of the case, under the display, is empty... Right where the card reader fits in a TI-59.
Awesome video ! I’m way too young for having ever been near this stuff, but nowadays .. I do find the Casios to be way easier to use ..
Darieee, they were more like a computer with a very limited user interface than a calculator. I like the Casio UI a lot. And graphing! I am amazed that someone has not created a hardware shield for the PI to take advantage of Mathematica. That would make a cool calculator.
tell me about it .. there's pretty much nothing that emulates what a normal casio scientific calculator does (the 20$ ones I mean) ... it took me ages to find an iOS app that would ACTUALLY SHOW the brackets ... Let alone have the ability to display fractions stacked and all the other goodies it has ... No idea why ... Apparently we're in the minority I suppose
The TI-58C and TI-59 were high precision computation programmable calculators, well ahead of anything else in their era other than the HP-55, HP-65 and HP-41C which were roughly the equivalent of the TI-58C and TI-59, and much more expensive. They were complete overkill for high school students, and were bought by university Physics, Chemistry and Engineering students along with professional scientists and engineers to replace the 10" Dual Base LogLog DeciTrig slide rule, which was still in use by those who couldn't afford the high prices of these calculators. A good slide rule didn't come cheap even though they were less than the calculators. Those slide rules did much, much more than simple multiplication and division with scales to handle all manner of sophisticated transcendental function computations (overkill for high school use). Small 6" versions could clip into a shirt pocket although the precision wasn't as good with the short length - but good enough for a very close estimates in the field and away from a desk. For those needing higher precision, there were 20" models. Ultimately the LCD screen calculators that used less power than LEDs superseded the ones with LED displays These were superseded by the programmable graphing calculators in the 1990's with large LCD screens.
Hope this gives you some insight into how the high end these were 40 years ago - at the pinnacle of calculator technology in their era. The TI-89 Titanium and TI-Nspire CX [CAS], along with the HP-50g and HP Prime G2 (rev D) are today's top end, and they're dirt cheap compared to how much a programmable scientific cost in the mid to late 1970's. The calculator market now is geared for students in high school and university. In the professional world, desktop computer applications have taken over. Laptops, tablets and cell phones can't be used on HS and university exams, or on college entrance exams like the ACT, SAT and GRE. Some of us still use a calculator for some applications in the field in industrial environments where a laptop is inconvenient or impractical.
The TI-58 & TI-59 were introduced to the public on May 24, 1977
Source: datamath.org/index.htm
Cool video btw; I have recently acquired a TI-59 and an even older SR-52 from ebay, both of which need repairs, so your video will be a valuable guide. Thanks for posting.
Greetings from Denmark.
Glad it can help. Always wanted to visit more than the Amsterdam airport in Denmark.
When you use USB power, does the polarity matter on the external plug?
Thanks!
I do not have a schematic so I can not say for sure, but it looks like the power from the adapter goes into the bridge rectifier so polarity probably does not matter.
Is it possible to use it from the currently available Lithium 3.7V batteries? I have one approx 1200mAh, brand new and I do not want any damage of the calculator when I plug the charger.
The NiCad pack was about 3.6v, and I run mine off of 5v USB, so I don't see why not.
@@grtyvr Thanks, but I mean, I solder the battery pack inside and I want to use the original TI charger, so I do not want to install eg. a TP4056 charger circuit with USB connector.
@@TizedesCsaba I suspect that the new battery charge profile is different from the old NiCad. But I am not an expert on that.
@@grtyvr Yes, I have asked an electrical engineer and he said, the overcharge protection for the Lithium batteries required, therefore the best solution install a TP4056 charger with USB. Only one question, how can I close the battery compartment without old battery...?!?
@@TizedesCsaba I just pulled out the batteries and left the cover undisturbed. That worked for me.
It is odd to see the chips piggy backed liked that in a professional instrument.