HP-15c: Why so popular?

[nickapos]

(11-04-2023 09:59 AM)Peet Wrote:  

(11-04-2023 09:12 AM)nickapos Wrote:  Awesome answer Valentin, especially for us who were not around at that time, to learn the history of these awesome machines and how they compare to each other at the time of their release.
Thank you very much
I was 4 years old when 15C was released

I don't think the comparison was meant seriously. Some advantages of the 41c are listed as disadvantages through a twisted description. The list is also a bit opinion-heavy instead of factual.

Compare a 15c and 41c is a bit like comparing a rowing boat and a sailing yacht. The 15c is a pocket calculator, the 41c a portable computer system. If you want an expandable system with external data storage, a printer and a huge software library, then the 15c doesn't offer much of that.

Yeah of course I know that 41c is expandable, but I did not realise that 15c was so feature full, and in general ahead of its time when it was released.

[Steve Simpkin]

(11-04-2023 09:47 PM)nickapos Wrote:  

(11-04-2023 09:59 AM)Peet Wrote:  I don't think the comparison was meant seriously. Some advantages of the 41c are listed as disadvantages through a twisted description. The list is also a bit opinion-heavy instead of factual.

Compare a 15c and 41c is a bit like comparing a rowing boat and a sailing yacht. The 15c is a pocket calculator, the 41c a portable computer system. If you want an expandable system with external data storage, a printer and a huge software library, then the 15c doesn't offer much of that.

Yeah of course I know that 41c is expandable, but I did not realise that 15c was so feature full, and in general ahead of its time when it was released.

I had forgotten that the TI-58/59 had so much of the HP-15C functionality built-in (with the included "Master Library Module ML-01") when it came out 1977, 5 years prior to the HP-15C.
https://www.hpmuseum.org/forum/thread-20...#pid179541

[Dave Britten]

(11-04-2023 10:08 PM)Steve Simpkin Wrote:  

(11-04-2023 09:47 PM)nickapos Wrote:  Yeah of course I know that 41c is expandable, but I did not realise that 15c was so feature full, and in general ahead of its time when it was released.

I had forgotten that the TI-58/59 had so much of the HP-15C functionality built-in (with the included "Master Library Module ML-01") when it came out 1977, 5 years prior to the HP-15C.
https://www.hpmuseum.org/forum/thread-20...#pid179541

It's a shame the TI-66 didn't retain module support, or at least have the Master Library Module built in. It could have been a viable alternative (I wouldn't go as far as to say competitor) to the 15C or even the 41C to an extent.

[Dwight Sturrock]

I started in college with a HP34C. Loved the RPN. Upgraded (1983?) to a HP-15C. Feature set was similar but the battery life alone was worth the upgrade.

Why it was popular with me?

1) RPN
2) Landscape format, size and feel of quality construction
3) Programmability
4) Solver
5) Battery life

I gave it to my sister, she used it in high school and for a math major in college.
Later she gave it back to me and I still use it at work.

[carey]

(11-04-2023 11:16 PM)Dave Britten Wrote:  It's a shame the TI-66 didn't retain module support, or at least have the Master Library Module built in. It could have been a viable alternative (I wouldn't go as far as to say competitor) to the 15C or even the 41C to an extent.

Yes, though it's slowness might have held it back. While the original 15c was no speed demon, the TI-66 was as slow as molasses. I tried one this year and could actually watch it thinking about nearly everything. Unfortunate because otherwise a nice calculator in size, layout, and simplicity.

[Eddie W. Shore]

Reasons why I like the 15C:

1. Compact, horizontal format like the 12C.
2. The screen is readable.
3. Solve and integrate functions.
4. All the comparison tests are available.
5. Five labeled keys (A-E).
6. Key codes: easy to locate the key.


The TI-66 is too slow to be a competitor, even though it shows the keys that has been programmed.

[Dave Britten]

(11-05-2023 04:10 PM)Eddie W. Shore Wrote:  Reasons why I like the 15C:

1. Compact, horizontal format like the 12C.
2. The screen is readable.
3. Solve and integrate functions.
4. All the comparison tests are available.
5. Five labeled keys (A-E).
6. Key codes: easy to locate the key.


The TI-66 is too slow to be a competitor, even though it shows the keys that has been programmed.

Yeah, the TI-66 is WILDLY slow - even its predecessor the 58C is twice as fast! It's got nice features and build quality though.

[Nigel (UK)]

(11-05-2023 05:16 PM)Dave Britten Wrote:  Yeah, the TI-66 is WILDLY slow - even its predecessor the 58C is twice as fast! It's got nice features and build quality though.

There is a double-speed mod for the TI-66, described here. It still isn’t fast, but it makes it nicer to use.

Nigel (UK)

[Steve Simpkin]

(11-04-2023 11:16 PM)Dave Britten Wrote:  

(11-04-2023 10:08 PM)Steve Simpkin Wrote:  I had forgotten that the TI-58/59 had so much of the HP-15C functionality built-in (with the included "Master Library Module ML-01") when it came out 1977, 5 years prior to the HP-15C.
https://www.hpmuseum.org/forum/thread-20...#pid179541

It's a shame the TI-66 didn't retain module support, or at least have the Master Library Module built in. It could have been a viable alternative (I wouldn't go as far as to say competitor) to the 15C or even the 41C to an extent.

Yes, aside from the larger memory and printer port, the TI-66 function set is much closer to the HP-11C than the HP-15C. The TI-66 lacks a solver, numerical integration, matrix operations and complex math. It would have been more of a competitor to the HP-15C if it had included the functionality in the TI-58/59's Master Library Module ML-01.

[etn]

(10-26-2023 08:27 AM)Peter Klein Wrote:  Pardon me if I question Doctrine here ;-). I’m curious why the 15c is so popular. Don’t get me wrong, it’s a very nice machine. HP managed to cram maximum possible goodness into a limited but lovely, elegant, durable package with a beautifully readable display. And I used an 11c as my daily driver for a dozen years, so I have some idea of how it feels.

The lovely, elegant, durable package in landscape format, as well as the simplicity of use, is what I love about the Voyager series. To me, the 15C is the most popular (vs. other Voyagers) because "people always want the best". I plead guilty too...

...But as a matter of fact, I use an 11C daily, not a 15C. I decided on an 11C because it has everything I need, and I paid a quarter of the going 15C price at the time I bought it. I packed it with the 4-5 programs I use for work. Even the more limited memory space of the 11C is overkill for them. I don't need complex or matrix capabilities. Whenever I need a solver, I reach to my 42s (now replaced by a DM42), due to its much better usability.

Of course, when the 15C-CE was introduced, I needed to get one

[Steve Simpkin]

One aspect that keeps coming up as a reason for the popularity of the HP-15C and other Voyager models is their "Landscape Layout". I find it very ironic that the original design of the Voyager series was a “normal” vertical format like every calculator HP had made previously. Among the design goals for these models is that they had to fit easily into a shirt pocket and had to withstand a 1 meter drop on all four corners (like all other previous HP calculators). Placing the LCD at the top of a vertical format calculator made it difficult to protect the LCD at this time without making the entire calculator bigger so they changed the design to a horizontal format to provide more protection around the display.

This and other great information about the HP-12C (and other Voyager models) were discussed by Dennis Harms in his HHC 2011 presentation: The HP 12C: Why Has it Lasted 30 Years?.
HHC 2011: The HP 12C: Why Has it Lasted 30 Years?

[tppytel]

(11-04-2023 11:00 AM)lvt Wrote:  I bought a TI-83 for my sister when she entered secondary school (called "lycée" in France), the calculator barely lasted those three years until she graduated.

That's actually rather surprising to me. The early TI graphing calcs were solidly built in my experience, provided you took reasonable care with the screen. The TI-85 I bought for PreCalc in 1993 still works just fine, and we still had a ton of 81/82/83's kicking around our high school when I started teaching in 2000. The fat 84's seemed OK too, but the current 84CE's seem to have gotten significantly worse. I have multiple students with ~1yo 84CE's that just died or refuse to charge, which really sucks for a ~$120 device.

As can be deduced from the dates above, the original Voyagers were well before my time. But they remain my favorite calculators for straight-up real number crunching for all the reasons others have noted. Even with a DM42 available I prefer grabbing a Voyager - better screen and keypad, and the form factor feels nicer to my hands. The downside is that programming is quite awkward on the Voyagers vs the DM42. However, I'll reach for the Prime if I need to do any significant complex or matrix calculations. I'm curious as to how many folks still professionally use a 15C for complex/matrix ops instead of more recent models.

[ijabbott]

(11-07-2023 10:36 PM)tppytel Wrote:  

(11-04-2023 11:00 AM)lvt Wrote:  I bought a TI-83 for my sister when she entered secondary school (called "lycée" in France), the calculator barely lasted those three years until she graduated.

That's actually rather surprising to me. The early TI graphing calcs were solidly built in my experience, provided you took reasonable care with the screen. The TI-85 I bought for PreCalc in 1993 still works just fine, and we still had a ton of 81/82/83's kicking around our high school when I started teaching in 2000. The fat 84's seemed OK too, but the current 84CE's seem to have gotten significantly worse. I have multiple students with ~1yo 84CE's that just died or refuse to charge, which really sucks for a ~$120 device.

One Achilles' Heel is the battery connection - spring steel wire resting on PCB pads, which they wear through, creating a hole in the PCB pad, so the calculator won't turn on. Easy to fix by bending the contacts a bit so they contact a different part of the pad, or better yet, by flooding the pads with solder.

[tppytel]

(11-08-2023 11:05 PM)ijabbott Wrote:  Easy to fix by bending the contacts a bit so they contact a different part of the pad, or better yet, by flooding the pads with solder.

Thanks. I'll keep that in mind next time one turns up non-charging.

[ijabbott]

(11-08-2023 11:24 PM)tppytel Wrote:  

(11-08-2023 11:05 PM)ijabbott Wrote:  Easy to fix by bending the contacts a bit so they contact a different part of the pad, or better yet, by flooding the pads with solder.

Thanks. I'll keep that in mind next time one turns up non-charging.

I was really referring to the older models that use AAA batteries.

[Geriatricus]

(11-05-2023 05:16 PM)Dave Britten Wrote:  

(11-05-2023 04:10 PM)Eddie W. Shore Wrote:  Reasons why I like the 15C:

[Good Reasons]

The TI-66 is too slow to be a competitor, even though it shows the keys that has been programmed.

Yeah, the TI-66 is WILDLY slow - even its predecessor the 58C is twice as fast! It's got nice features and build quality though.

I loved both my 58C and 66, but I noticed that over the years, the 66's keys, especially toward the bottom, became depressed by the storage sleeve. I had to leave it out.

[Geriatricus]

For me, the 15C has represented the miracle of capability in minimal space with decade long battery life. In addition to a few battery swaps, I've replaced the feet on mine with neoprene that cost less than $1.

Haiku meets tech.

[desertdawg]

What is it?
Your father's HP-15C.
This is the weapon of a real engineer.
Not as clumsy or random as a TI.
An elegant weapon for a more... civilized age.

[Johnh]

(02-24-2024 05:34 AM)desertdawg Wrote:  What is it?
Your father's HP-15C.
This is the weapon of a real engineer.
Not as clumsy or random as a TI.
An elegant weapon for a more... civilized age.

For over a generation, the HP Engineers were the guardians of accuracy and durability at the old Hewlett Packard. Before the dark times, before the SMARTPHONE.