Calc recommendation - self-study college math refresh

[HPing]

I am self-studying "forgotten" math from college days. Kindly recommend a beginner scientific calculator.

I have a lot of HPs at work
- 12c - love the interface and rpn
- 19b - clunky and cracked easily. uninspiring
- 17b - Ok but not too inspiring

I also had some inexpensive casio scientific calculators in college that were nice.

Tempted by a 15c (vintage or collectors edition). Or maybe some graphing calculator. The HP Prime seems a bit extreme.

[Johnh]

Based on what you describe, and that you like and are fxmiliar the 12c I reckon that's pointing you directly to a new 15c-ce!

But the SwissMicros range of modern reimagining of classic hp RPN machines is appealing too.

I'm finding my '15 a great companion to my late-career technical work, and also remembering and exploring maths from several decades ago. You could check it out as an mobile phone emulation too.

My view is that these days, any task that needs more that can quickly do, is better done with a spreadsheet or other pc-bsed tool.

[carey]

(08-11-2024 12:39 AM)HPing Wrote:  I am self-studying "forgotten" math from college days. Kindly recommend a beginner scientific calculator.

I have a lot of HPs at work
- 12c - love the interface and rpn
- 19b - clunky and cracked easily. uninspiring
- 17b - Ok but not too inspiring

I also had some inexpensive casio scientific calculators in college that were nice.

Tempted by a 15c (vintage or collectors edition). Or maybe some graphing calculator. The HP Prime seems a bit extreme.

Since your stated purpose is to self-study forgotten math and mention college math in your subject line, and since your objection to the Prime was that it’s extreme and didn’t mention it’s weakness in RPN, a great calculator to consider for college math self-study is the algebraic HP39GS.

-there’s loads of math instructional materials
-graphical
-USB computer connection
-inexpensive (even new ones can sometimes be found for around $35)
-it’s the same App-based UI that started with the 38g and evolved into the Prime
-advanced matrix functions including SVD
-Programmable in a powerful version of BASIC

Note that the 15C is a remarkable calculator, but it’s not what comes to mind first to self-study forgotten college math.

[John Keith]

(08-11-2024 02:24 AM)carey Wrote:  

(08-11-2024 12:39 AM)HPing Wrote:  ...
I have a lot of HPs at work
- 12c - love the interface and rpn
- 19b - clunky and cracked easily. uninspiring
- 17b - Ok but not too inspiring

...

Tempted by a 15c (vintage or collectors edition). Or maybe some graphing calculator. The HP Prime seems a bit extreme.

Since your stated purpose is to self-study forgotten math and mention college math in your subject line, and since your objection to the Prime was that it’s extreme and didn’t mention it’s weakness in RPN, a great calculator to consider for college math self-study is the algebraic HP39GS.

-there’s loads of math instructional materials
-graphical
-USB computer connection
-inexpensive (even new ones can sometimes be found for around $35)
-it’s the same App-based UI that started with the 38g and evolved into the Prime
-advanced matrix functions including SVD
-Programmable in a powerful version of BASIC

Note that the 15C is a remarkable calculator, but it’s not what comes to mind first to self-study forgotten college math.

Since the OP did mention RPN as being desirable, I would think that a 48GX or 50g would be preferable. It is hard to find either in good shape at a reasonable price so the "inexpensive" criterion would not be met. A nice in-between alternative might be the Swiss Micros DM42.

[Allen]

(08-11-2024 12:39 AM)HPing Wrote:  I am self-studying "forgotten" math from college days.

With deference to the original question and the esteemed crowd here. I had a similar journey a few years ago and discovered a fun hobby while self-studying college math.

I determined that I would learn python through working the Project Euler problems. This avenue reviewed many math topics, introduced new math areas I'd never heard about in Engineering, while also providing a more transportable skill for the workplace than, say, programming 30+ year old calculators. (Which I have many dozens of !!)

Squeezing some of these into 100-byte programs is a fun challenge in itself and I've managed to solve many on HP 41c/32s/42s (e.g. the first dozen problems or so). But if one only solves the problems that are portable to a HP calculator, we are skipping many challenging and interesting math problems that don't fit easily into our beloved antiques.

For example, I learned a great deal solving \(P(28)\) from P886, but it took many GB of RAM to hold the intermediate tables. (Clearly not the approach needed to solve the final answer.) Recursively solving higher \(P(x)\) has required more creativity and learning some new math tricks that I would not have found if I was only trying to solve a smaller version of this problem that could be run on a handheld machine.

(The Anaconda distribution linked above costs $0)

[avsebastian]

(08-11-2024 02:24 AM)carey Wrote:  

(08-11-2024 12:39 AM)HPing Wrote:  I am self-studying "forgotten" math from college days. Kindly recommend a beginner scientific calculator.

I have a lot of HPs at work
- 12c - love the interface and rpn
- 19b - clunky and cracked easily. uninspiring
- 17b - Ok but not too inspiring

I also had some inexpensive casio scientific calculators in college that were nice.

Tempted by a 15c (vintage or collectors edition). Or maybe some graphing calculator. The HP Prime seems a bit extreme.

Since your stated purpose is to self-study forgotten math and mention college math in your subject line, and since your objection to the Prime was that it’s extreme and didn’t mention it’s weakness in RPN, a great calculator to consider for college math self-study is the algebraic HP39GS.

-there’s loads of math instructional materials
-graphical
-USB computer connection
-inexpensive (even new ones can sometimes be found for around $35)
-it’s the same App-based UI that started with the 38g and evolved into the Prime
-advanced matrix functions including SVD
-Programmable in a powerful version of BASIC

Note that the 15C is a remarkable calculator, but it’s not what comes to mind first to self-study forgotten college math.

ohhh..... but , the hp 39gs has no CAS

For engineering studies, is great, but for mathematics??? I think it is more advisable hp 48g, hp 49g, hp 50g, hp 40g

[carey]

(08-12-2024 01:24 AM)avsebastian Wrote:  ohhh..... but , the hp 39gs has no CAS

For engineering studies, is great, but for mathematics??? I think it is more advisable hp 48g, hp 49g, hp 50g, hp 40g

1) Given that the op was considering a 15C and also mentioned the possibility of a graphing calculator, and said the hp prime was extreme, it seems that the op’s calculator interest for math self-study is more numerical and graphical than symbolic, i.e., more like the hp equivalent to a TI-84.
2) The HP39gs has some limited symbolic capability in that it can perform symbolic (yes, symbolic) differentiation of some functions.
3) If a full CAS system is needed, the HP40gs is an alternative consisting essentially of an HP39gs with a CAS system grafted on and is the later and more easily found usb version of the HP40g that you mentioned. (Note that the 40g was not sold in the U.S.). The 40gs CAS is available by selecting the CAS softkey and unfortunately is not well-integrated with Home - a situation that continued into the hp prime.

[HPing]

Thank you all for your thoughtful responses. i now have a foundation to do some research...lots of options!

I think this is a recap of some suggestions:

48g, 48gx, 49g, 50g

39gs, 40g, 40gs (algebraic, first without CAS)
SwissMicros DM42 etc.

Prime
TI-84

15c-ce

[CheshireChris]

(08-11-2024 12:46 PM)John Keith Wrote:  Since the OP did mention RPN as being desirable, I would think that a 48GX or 50g would be preferable. It is hard to find either in good shape at a reasonable price so the "inexpensive" criterion would not be met. A nice in-between alternative might be the Swiss Micros DM42.

I've just bought a 50G in "as new" condition for £100 on eBay, so they are out there. Less than half the price of a DM42, lovely though that is.

[carey]

(08-15-2024 01:13 PM)CheshireChris Wrote:  I've just bought a 50G in "as new" condition for £100 on eBay, so they are out there. Less than half the price of a DM42, lovely though that is.

Yes, while more a calculator user than collector, I've noticed that 50g prices appear to now be around the lowest I've seen except for the period of time just before their end of production.

[Maximilian Hohmann]

Hello!

(08-15-2024 01:13 PM)CheshireChris Wrote:  I've just bought a 50G in "as new" condition for £100 on eBay, so they are out there. Less than half the price of a DM42, lovely though that is.

And if RPL is not your thing (I never got the hang of it) then a real HP-42S might be an option as well. I recently found one on eBay in Germany for 150 Euro, which is really not the kind of money I usually pay for LCD calculators from the late 1980ies, but since there are so few gaps in my collection now I sometimes tend to overspend a little... I saw another one for a similar price on (eBay) classifieds in Germany, but I have not checked if it is still there. It beats an HP-15C by a wide marging, but of course it is a newer calculator: Much bigger display, alphanumerics, more memory. The only drawback is the total lack of external storage.

Regards
Max

[John Keith]

(08-15-2024 02:13 PM)Maximilian Hohmann Wrote:  ... Much bigger display, alphanumerics, more memory. The only drawback is the total lack of external storage.

Though the display is larger, the contrast is poor compared to the Voyagers.

[HPing]

Thank you all for the responses. Learning why people have several calculators. Still noodling but my ideas now:

Top 3 for now (need to decide!)
- 42s - A tank with the easy menus. The mediocre screen contrast is OK for my eyes (I used one before).

- 48 - Great documentation and build. Popular screen/ key issues look easy to fix (but opening the shell is really difficult). More rare screen delamination seems to require a replacement screen, although I see people on the HPC forums removing a screen layer for cleaning, no sure that is possible with these.

- 50s - Good overall. Less documentation, construction quality, and style. Less expensive

Future ideas:
- 15se - Great build, 16c mode & supports Moravia. Seems less intuitive so maybe not first buy (anyways I have several 12c models for basic maths)

- 42DM - Good overall, updates including c47, supports SwissMicros. Expensive, dealing with updates; the nits would bother me.

Discounted daily
- 39gs / 40gs - Inexpensive options (latter with CAS albeit not ideally integrated). Might get one for travel.

[HPing]

Last night I found an old 17Bii in the drawer. Perfect way to test drive a basic 42s for a few days.

It is in good nick. However...the algebraic expressions and back arrow are not cooperating (unless gently pressing the right side of the screen bezel.)

Since this calculator has no real value, I don't mind ripping it apart to clean and installing some foam following the videos below. But first, I will try stuffing rubber into the battery compartment:

HEPATCA commented in YouTube, "Here's a simple fix to try without opening the calculator up. Remove the battery cover. Take a small rubber grommet, about 3-4mm thick, and insert it into the space between the case and PCB. it should be snug. Then with a small screwdriver gently push the grommet further in about 1cm, be careful to avoid the processor IC. When in place this grommet applies a bit of pressure between the back of the case and the processor PCB, which in turn pushes the processor PCB into the keyboard flex cable contacts. Half the keys on my 32SII were intermittent -- this simple fix brought it back to life."

Logan West repair
https://www.youtube.com/watch?v=Uo4EZG0NQbc

Jaron Ball repair
https://www.youtube.com/watch?v=2yoqtIJlkNM

[HPing]

Stuffing a piece of rubber in the back via the battery compartment fixed the keys. Can't get the door back on so will have to sort that later on.

[rprosperi]

(08-26-2024 03:40 AM)HPing Wrote:  Stuffing a piece of rubber in the back via the battery compartment fixed the keys. Can't get the door back on so will have to sort that later on.

Thanks for confirming this seemingly easy fix, but could you (or someone that has successfully used this repair technique) please post a photo showing exactly where the piece of rubber is inserted?

[HPing]

(08-26-2024 10:50 AM)rprosperi Wrote:  Thanks for confirming this seemingly easy fix, but could you (or someone that has successfully used this repair technique) please post a photo showing exactly where the piece of rubber is inserted?

I'm sure there are better resources at the hpmusuem but this is what I found. Still trying to optimize it so the battery compartment can be closed.

Since the root cause seems to be deteriorating factory foam near the screen, I suppose this fix is not permanent.

The Voyager calculators had different internals. Our 17Bii (made in Indonesia) had a metal shield behind the screen which can be seen when removing the battery cover. Some Voyagers don't have that metal shield

We first tried some reasonably dense foam (used for outdoor waterproof electrical outlet covers). That only helped a few buttons; it was either too thin or too soft.

We cut a flat, round black plumbing washer in half, stuffed it partly in the left-bottom-side of the battery compartment between the back plastic case and the metal shield. The washer pushes the metal shield towards the screen.

All the buttons and self test are fine. Screen looks fine. However, we can't get the battery door back on.

There is some risk of damage when stuffing foam or rubber via the battery box. Note the big chip near the battery compartment. Other risks include: dislodging/breaking components, cracking the PCB, lifting traces on the PCB, crushing the screen, chemical reactions, etc.). IME foams and rubbers just seem to deteriorate over time and with exposure to other materials; some get conductive which is not ideal.

These two videos show what is "below" the battery compartment for two Voyager calculators (one with the metal shield and one without). HEPATCA's pinned comment in the second video gave me the idea for the battery compartment foam.

https://youtu.be/2yoqtIJlkNM?si=KzCVGIOfUi_bDi-2&t=207
https://youtu.be/Uo4EZG0NQbc?si=hx2mD3FAE4CuSTLc&t=119

I'll post a photo and more rubbery ideas once I get this optimized.

[HPing]

(08-26-2024 10:50 AM)rprosperi Wrote:  Thanks for confirming this seemingly easy fix, but could you (or someone that has successfully used this repair technique) please post a photo showing exactly where the piece of rubber is inserted?

Unfortunately, this "easy fix" has not lasted more than a few weeks. The four arithmetic operators no longer work.

Whilst the 48sx repair video by Ben Heck Hacks was highly entertaining, it dampened my desire to service one. https://www.youtube.com/watch?v=ZrVQ8SyQ4EU

Also, I decided on a HP 50G which arrives this week. It seems refined and reliable, despite the clownish industrial design.

And I picked up the 50G tutorial video (7 hours!). I only found one reference to those videos here. But they have a few chapters on youtube giving a flavor for the course. I'll go through the whole course and provide quick impressions later this month.
https://www.mathtutordvd.com/products/Th...lume-1.cfm

[HPing]

After a long wait, both the 50G and the DVDs arrived today.

The DVDs came from Tampa Bay but somehow landed in new condition, on time.

The 50G, however, has three totally dead key that I can't get to work. Made new thread on key repair attempt
https://www.hpmuseum.org/forum/thread-22517.html