The HP-33E/C that could have been.

[Steve Simpkin]

(01-07-2023 09:19 AM)Kostas Kritsilas Wrote:  Going strictly from memory of those days, I believe that the contemporary calculator for the HP-25/25C was the TI-58/58C. and the TI-58/58C had 480 partially merged program steps, maximum (I seem to recall that you could re-allocate program steps to registers). The HP-67 (224 fully merged steps) equivalent was the TI-59 (960 partially merged steps). The later HP-29C had 98 or 100 fully merged steps, and a bunch of added programming features over the HP-25/25C like indirect addressing and subroutines, some of which were in the TI-58/58C already.

The earlier generation programmables were the HP-55 (49 un-merged steps) and HP-65 (100 un-merged(?) steps) vs. the SR-56 (100 un-merged steps) and SR-52 (I don't remember how many steps it had). I also don't recall the register counts for each.

It is interesting to look at the U.S. street prices for these TI models when they were introduced compared to HP models at the time.

When the TI-57/58/59 were introduced around May 1977, the TI-58 was the same price ($100) as a HP-25. The TI-58 was much cheaper than the HP-29C ($159) which was introduced around the same time. The following advertisement is from the October 1977 issue of Popular Electronics magazine.
   


Just a few months earlier (June 1977) the following ad from the same magazine shows the SR-56 selling for considerably less ($79) than the HP-25 ($116) at that time.
   

The TI-58C appears to have been introduced sometime in 1979, the same year as the HP-34C and HP-33C. Interestingly TI did not create a CMOS version of the memory chip used in the TI-58. Instead they bought a standard CMOS RAM chip (RCA) and developed a custom chip to interface to it. The result is a substantial redesign of the PCB.
http://www.datamath.org/Sci/WEDGE/TI-58C.htm