The dark side (Ti-59)



#20

I hope I'm not going to be banned for daring look at the other side! :) And I thought you guys here could help me...

Basically, after lusting over the HP-67 for years (it's my personal holy grail), I realized I just can't justify spending so much money on a calculator; then I found on eBay many auctions for the Ti-59. It looked like a solid and "serious" calculator, and it had a mag strip reader... So I placed some bids. I got one (calculator only, with leaky battery but contacts OK) for about $20, and another one (with PC-100 printer, no battery, no corrosion) for about $25. I thought that maybe I could make at least one fully working...
One came with its (US) power supply. Since I was in the US at the time, I tried it, and it had some weird behaviors... it would basically run, but after doing something that involved programming or registers, it would hang. The weird thing is that after it hung, even power-cycling it wouldn't help... it had to be left off and disconnected for quite a long time before it would work again. I assumed a dead/dying memory chip...

The other was working perfectly. But since the PC-100 had no key (I know, I should have checked) I had to physically dismantle it to be able to remove the calculator.

Anyway, back to Italy, I tried powering them up with a stabilized 5V power supply, and... they both seem to work perfectly! They pass the self test, and they read cards without problems. I'm amazed... no "gunky wheel" problem here! What could have caused the first one to start working fine? It could seem like a power problem...

I used a 5V power supply because the original is a standard transformer that provides 3.3V AC; but being the US version, made for 110V, I couldn't use it; and I read somewhere that a 5V CC can be used instead, because the diodes in the rectifier keep the voltages at acceptable levels. Do you think this is correct?
The calculators don't seem to complain, they both work perfectly. After several minutes of use, the ROM stack and the diodes get slightly warm, but not hot. Should I stop using this supply? I wouldn't know how else to power them, as I can't source a proper "official" 220V supply...

Thanks,
Cristian


#21

Hi!

The Ti-59 (and similar ones from Ti) is like an HP woodstock in the sense that the battery is part of the power supply. It is required for rectifying, stabilising and limiting the voltage when the primitive wall charger is used. So either you put a good battery in place or supply it from a stabilised 4,5 to 5V supply.

For rebuilding the battery pack, I use 800mAh NiMH AAA cells instead of the original AA cells. At 800mAh they hold almost twice the power of the original NiCD cells and are much easier to get into the very tight battery holder.

The Ti59 is a wonderful calculator and superior to the Hp-67 in many respects. More memory, solid state ROM modules, more functions, printing capability (even alphanumeric) and it can be used by my wife and son :-) Unfortunately, it has one of those terrible Ti keyboards that will inevitably start to suffer from incurable key bounce after some time of usage.

Saluti,
max


#22

Hi Maximilian, thank you for your reply!
So I can keep using this 5V supply? Good to know... Do you know if it will also be able to recharge the battery pack, once I rebuild it?

I've seen reported in various places that the TI is actually more advanced than the HP-67, but I just love the HP feel... And the TI isn't RPN! :)

The keyboards in both these calcs are fine, with no bounce. Have I just been lucky? Working mag card readers, working electronics (at least with this power supply), working keyboards... Or do the TI's just stand better the test of time?

Cristian


#23

Quote:
So I can keep using this 5V supply?

Should be no problem! The PC100 printer also supplies 5V I think.

Quote:
Do you know if it will also be able to recharge the battery pack, once I rebuild it?

5V stabilised will probably not be sufficient to charge the battery pack. But you can keep looking at eBay for Ti chargers, they are not expensive. The Ti58 and 59 chargers are identical.

Quote:
And the TI isn't RPN! :)

No, it's actually better than RPN! Ten levels of parentheses, algebraic operator precedence and the magical "=" key. Who needs RPN if he can have all that? My Ti59 brought me through my final two years at school (at Varese, Italy by the way) and all the way through university and I didn't miss RPN for a single second.

Quote:
The keyboards in both these calcs are fine, with no bounce. Have I just been lucky? Working mag card readers, working electronics (at least with this power supply), working keyboards...

Lucky indeed! Electronics and card reader are reliable, but the keyboards not too much.

Quote:
Or do the TI's just stand better the test of time?

Mind you, they were not cheap calculators then. Built to last! The price of a Ti59 was about one half of an HP67 but that was still an awful lot of money, simply because HPs were so outrageously expensive then. We always said HP stands for "high price"...


max


#24

Quote:
Mind you, they were not cheap calculators then. Built to last! The price of a Ti59 was about one half of an HP67 but that was still an awful lot of money, simply because HPs were so outrageously expensive then. We always said HP stands for "high price"...

I bought a HP-67 in 1977, and later that year also bought a TI-59 with PC-100A printer.

The HP-67 was $450 ($1710 in 2012 USD), the TI-59 was $300 ($1140 in 2012 USD), and the PC-100A was $150 ($570 in 2012 USD). You are very correct about none of these being inexpensive at the time they were introduced.

I agree that the TI-59 with PC-100A was far more capable and technically advanced than the HP-67. However, the TI hardware was much less reliable...I went through five TI-59s and three PC-100s between 1977 and 1981. In contrast, my HP-67 required only one return to the factory, four years after purchase. Thus, for my professional engineering requirements (on a nuclear submarine) the HP-67 was the only satisfactory choice. My TI gear was relegated to recreational hobby use in that era when a real personal computer (Polymorphic Systems, Processor Technology Inc., Ohio Scientific, etc.) was well beyond my financial resources as a navy lieutenant.


#25

Hi!

Quote:
The HP-67 was $450 ($1710 in 2012 USD), the TI-59 was $300 ($1140 in 2012 USD), and the PC-100A was $150 ($570 in 2012 USD). You are very correct about none of these being inexpensive at the time they were introduced.

Here in Europe, the difference in price was far bigger! My Ti59 cost around 450 german mark, whereas an Hp-67 was priced at 1100 to 1200 then. During my time at university (1980-86) I never saw a student use an Hp calculator. Not one. Simply out of reach.

Quote:
I went through five TI-59s...

Wow. I still have my first one from 1978 and it still works. I had to send it for repair once because someone dropped it from a lab table.

Quote:
In contrast, my HP-67 required only one return to the factory...

My dad (who worked in civilian nuclear research) still has the Hp-67 that his employer bought him around 1977. It still works fine without ever needing any maintenance (can't tell about the card reader).

Regards
max


#26

Quote:
Here in Europe, the difference in price was far bigger! My Ti59 cost around 450 german mark, whereas an Hp-67 was priced at 1100 to 1200 then.

Some time ago I compiled some prices for the TI 58/59 and HP-67/97/41, taken from contemporary computer magazines, e.g. overviews with suggested retail prices as well as street prices in ads placed by some major mail order stores. Let's consider the situation in Germany around 1980:
  • TI-59: from 550 DEM in 1979 down to 399 DEM in 1981/82
  • HP-67: from 779 DEM (late 79) down to 745 DEM in 1980/81
  • HP-97: essentially the same 1499 DEM from late 79 to 81
Service for our forum members from the US: 1 DEM ~ 0,55 USD in 1979, ~0,50 USD in 1980 and slightly less in 1981.

Yes, the HPs were more expensive than the TIs, but it's essentially the same ratio as the suggested retail prices in the US back then.

Quote:
During my time at university (1980-86) I never saw a student use an Hp calculator. Not one. Simply out of reach.

Strange. Both I and three of my classmates started using HP calculators (34C, 41C/CV) in 11th grade at school. And at university the 41-series was not exotic at all.

Dieter


Edited: 8 Jan 2013, 5:30 p.m. after one or more responses were posted


#27

It's probably a matter of age. I left school in '77. I started my student life with a SR-56 accompanied (some time later) by a PC-100A. The SR-56 was later replaced by a TI-59 which fit the same printer and added a whole new world of programming capabilities. HP calculators were very rare back then. I was deeply impressed by an early HP-41C but switched away from calculators all together shortly thereafter (replaced them by access to the IBM mainframe via punched cards and my TRS-80 clone at home.)

#28

Quote:

I bought a HP-67 in 1977, and later that year also bought a TI-59 with PC-100A printer.

The HP-67 was $450 ($1710 in 2012 USD), the TI-59 was $300 ($1140 in 2012 USD), and the PC-100A was $150 ($570 in 2012 USD). You are very correct about none of these being inexpensive at the time they were introduced.


The US price matches the italian price for that time (790,000 Liras, 2,500 EUROS nowadays), for that reason the choice of my father (EE) was in buying, as starting calculator, instead, the HP25C, with no mags, but a continuous memory.........and a lot cheaper..("only" 350,000 Liras!)


#29

Quote:
The US price matches the italian price for that time (790,000 Liras, 2,500 EUROS nowadays), for that reason the choice of my father (EE) was in buying, as starting calculator, instead, the HP25C, with no mags, but a continuous memory.........and a lot cheaper..("only" 350,000 Liras!)

Those 350.000 are quite the same price my father paid in late '79 for a 41C during my second university year. In my class there were a couple of TI 58C, an HP-34C and my 41... and lotsa no name calcs ;-).

Massimo

#30

Quote:
The keyboards in both these calcs are fine, with no bounce. Have I just been lucky?
No, you just kept your keyboard clean. Years ago I aquired some TI-59, all with bouncing or unresponsive keys. Looked like the usual TI problem but turned out to be just dirt. After cleaning with my favourite calc cleaner 'Sidol Ku"chenkraft', the keyboards were perfect (and they still are).

#31

Quote:
No, you just kept your keyboard clean.

You cannot imagine how clean I always kept the keyboard of my Ti59 (back in the dark ages when I needed a pocket calculator) :-)

And yet, it started bouncing. Worst are keys "3" and "0". So bad, that sometimes I rearranged the input values in a way that avoided those two numbers...


#32

Quote:
You cannot imagine how clean I always kept the keyboard of my Ti59 (back in the dark ages when I needed a pocket calculator) :-)
IIRC, there's a layer of foam which dissolves over the time. Guess this is what happens to your sample. I removed the foam completely in the course of cleaning.
#33

I used a 58c and 59 for years and did not have any keyboard problems. I did always keep them clean though, putting them down face-down when not using them so dust would not settle in, and if I did see a speck of dust or dandruff, I'd hold the calc upside down and clean it off. I would never put a calculator in a pocket where it could collect lint (or worse, fall out on the floor).

#34

Thanks everyone for the replies and insight!
I have to add though that the first calculator (the one that "used to" hang) hung again today. I had plugged it in with my 5V power supply and a make-shift battery pack, and just left it on for a while (with "0" displayed) and after a few hours went to check it... the "0" was still there, but no response to keypresses. Even after power-cycling it, even after removing all power sources. Turning it back on would just show a non-responsive "0".
After about 10 minutes of being left to "cool down", turning it on showed the "0" but pressing any button would show "9.999999999 99" and then hang there.
After another 30 minutes of cooling, it started working again.

Could this really be temperature-related? If it is so, would it more likely be a chip problem, or a discrete component? Any hints? :)

Cristian


#35

If some of the TI experts don't nail it, I'd be looking for either a poor solder joint or a failing capacitor. I'm guessing you're seeing the fault when the internal temperature gets too high for some period.

One way to test this would be to keep the battery attached the next time it locks up and see if it still recovers after it cools down for a bit.

Cheers,
Bob


#36

Quote:
One way to test this would be to keep the battery attached the next time it locks up and see if it still recovers after it cools down for a bit.


It does! I just tried, and the behavior is the same with and without battery, and with and without power supply. It just has to be left off for some time before it can be used again.
Should I try running a continuous program while keeping it in the refrigerator, to see if it doesn't hang? :)

Anyway... This calc doesn't have electrolytic capacitors, so I don't even have the proper spares at home... :/

Cristian


#37

Quote:
Anyway... This calc doesn't have electrolytic capacitors...

It has a couple of tantalum capacitors (IIRC, haven't opened mine for some years), but those are supposed to last forever. I rather believe in some bad solder connection. Have you tried running it from batteries alone for some time? I don't remember the calculator getting warm when run with batteries. Only when the charger is connected, the battery pack itself gets quite warm.

#38

Look here for the TI-59 Service Manual:

http://www.rskey.org/CMS/index.php/the-library/12

Check the IC power supply voltages when using your 5V supply. They should be about -10V and -16V. If they're in range then you won't damage the ICs at least.

I run a TI-58 often on a cell phone Li ion battery of about 4V. See:

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv019.cgi?read=169006#169006


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