Thursday, January 31, 2013

The TI-59

The TI-59 was Texas Instrument's successor to the SR-52 and answer to the HP-67. It came out in 1977, just after I bought my SR-52, of course. It quadrupled the number of program steps and added ROM program modules. It still did not have constant memory so that every time you turned it off, you lost  your program. Thus it still featured a magnetic card reader. The cards were not compatible with the SR-52. 
The TI-59 was TI's top of the line calculator until it was discontinued in 1983, although it became less relevant in 1979 when the TI-58C was introduced which had constant memory and cost much less. In 1983 both were replaced by the TI-66.
I never had one of these back in the day since I had already committed to the SR-52. Currently, these calculators are not as desirable as the old HP's and they can be found cheap on eBay. This one is the product of two eBay purchases used to produce one fully working example. 

The PC-100A printer cradle and charger was introduced with the SR-52. It was larger and clunkier than the HP-97 combined package, but it had the advantage that you didn't have to buy two expensive calculators to have both a desktop and a portable programmable calculator. 
This example was not working when I bought it on eBay, but I was able to repair the printer. I also swapped out some parts from another non-working one to produce one that is both clean and working. The paper it uses is a non-standard size but I was able to find new blank rolls from a guy in Romania (also on eBay).
I accumulated a few accessories including a case, blank program cards, Master ROM pac and also the Leisure ROM pac.

Tuesday, January 29, 2013

SR-52 vs. HP-67

Before there was iPhone vs. Android. Before there was MAC vs PC. Before there was IBM vs Microsoft. There was Texas Instruments vs. Hewlett Packard. In 1976 I was in the market for a calculator and the two top-of-the-line calculators were the SR-52 from TI and the HP-67 from HP. Both were fully programmable and came with a magnetic card readers that allowed to store and load programs. I ended up getting the TI, mostly because it was cheaper. The two brochures shown here are ones that I used to help make my decision.

The first fully programmable calculator with program storage was the HP-65 introduced by HP in 1974 with an MSRP of $795. TI came with a response in 1975 - the SR-52 with a price tag of $395. Here's my original, purchased in December 1976 when I was a sophomore in high school.  I used this calculator all through high school and college and it served me well.
After years of sitting, the battery compartment corroded and the card reader stopped working. After more years the calculating unit itself fried and started to answer with jumbled displays.
I set out recently to restore it. Repairs included a rebuild and tuning of the card reader, rebuild of the battery pack and replacement of the main processor board (from a donor calculator). It now is fully working.

 I still have all the original stuff that came with the SR-52 including the Game pac and blank magnetic card pac. Original sales receipt too from 47th Street Photo, December 8th, 1976 showing a big discount off of retail price!
 The HP-67 was introduced by HP in 1976 in response to the SR-52. It bettered the specs and also had the well respected HP engineering and design. Big difference was that it was RPN instead of Algebraic entry.  If I had the resources back then, I probably would have picked it over the TI, but it cost twice as much - $450 - and this price was never discounted.
The  one shown here I purchased recently on eBay. Actually, I bought two of them and chose the best parts from both to make this one. Both of them needed the card reader repaired. I ended up selling the other one for enough to pay for both.

Here are some HP-67 accessories including a leather case (which is really from an earlier HP-65), an owners manual, a charger and the Standard Pac of magnetic cards. The charger needed a power transistor replaced.

 The companion to the HP-67 was the HP-97. It has the same capability but with a built in printer and larger keys and display. New, this cost $750 back in 1976. I found this one on eBay. It needed a thorough cleaning, painting and the printer and card reader repaired. Now it's fully working.

Accessories that I have for the HP-97 include case, charger, owners manual and Standard Pac manual.

Finally, a picture showing both HP-67 and HP-97 together, just like in the brochure.