HP-12C / HP-12CP CPU stress test using date operation

[lvt]

As I use quite often the date function of my HP-12CP, I decided to make a little piece of code to test the calculator's real life durability.

The code will display dates from October 15, 1582 to November 25, 4046 (or 899,999 date operations) on the calculator's screen.

The test is expected to last at least a week and will required a new pair of CR2032 batteries (replaced one by one to keep it running).

The screen is set to maximum brightness (to take clear pictures from time to time).

The code :

Quote:1. 36
2. 42 6
3. 1
4. 43 16
5. 43 33 003
6. 43 33 000

Usage: DD.MMYYYY + R/S

[Eric Rechlin]

While I applaud your creativity, I don't think this is a very meaningful durability/torture test. This is basically just torturing the CPU, which really should be able to handle a test like this for months or years at a time. With these calculators it will probably be something at a more visible level that will fail -- maybe a key switch will wear out, or plastic in a button will fatigue, or a capacitor will get too old and degrade from time, or something caused by physical damage to the calculator (like running it through a snowblower or dropping it from an airplane).

[lvt]

(02-05-2023 04:08 PM)Eric Rechlin Wrote:  While I applaud your creativity, I don't think this is a very meaningful durability/torture test. This is basically just torturing the CPU, which really should be able to handle a test like this for months or years at a time. With these calculators it will probably be something at a more visible level that will fail -- maybe a key switch will wear out, or plastic in a button will fatigue, or a capacitor will get too old and degrade from time, or something caused by physical damage to the calculator (like running it through a snowblower or dropping it from an airplane).

Well, I managed to drop my 12C from my desk to the tile floor, one corner is slightly bent, and that's it.

BTW, the test I mentioned above didn't finish the way I wanted because the batteries die too quick.

[John Garza (3665)]

You could always program your handy-dandy HP button pusher to put it through it's paces...

-J

   

[Peter Klein]

Go to the zoo. Feed the calculator to a hippopotamus. Retrieve it later, clean and retest. An original 12c passed this test. Will the 12c Platinum?
;-)

See the bottom item under “Features,” here:
https://www.hpmuseum.org/hp12c.htm

[lvt]

(10-20-2023 08:13 PM)Peter Klein Wrote:  Go to the zoo. Feed the calculator to a hippopotamus. Retrieve it later, clean and retest. An original 12c passed this test. Will the 12c Platinum?
;-)

See the bottom item under “Features,” here:
https://www.hpmuseum.org/hp12c.htm

Thanks for your suggestion but I don't believe in that story. A zookeeper using the 12C Financial calculator to do elementary school math... No thanks ?

BTW, while hippopotamus are mainly herbivore, they have been seen eating dead animals. So their digestive fluid is pretty powerful, I doubt that a consumer electronic item like the 12C would survive the journey without being crushed or melted.

[Steve Simpkin]

(10-21-2023 03:31 AM)lvt Wrote:  Thanks for your suggestion but I don't believe in that story. A zookeeper using the 12C Financial calculator to do elementary school math... No thanks ?
...

That's exactly what I use my HP-12C for, elementary math I like the form factor and don't have an HP-11C (anymore) or an HP-15C. If I need to do anything more than basic math I reach for my HP-48SX.

[lvt]

(10-21-2023 04:47 AM)Steve Simpkin Wrote:  

(10-21-2023 03:31 AM)lvt Wrote:  Thanks for your suggestion but I don't believe in that story. A zookeeper using the 12C Financial calculator to do elementary school math... No thanks ?
...

That's exactly what I use my HP-12C for, elementary math I like the form factor and don't have an HP-11C (anymore) or an HP-15C. If I need to do anything more than basic math I reach for my HP-48SX.

Yes but old HP 12C only does RPN.

What kind of zookeeper uses RPN for his job on a daily basis, huh?

[Peet]

(10-21-2023 05:48 AM)lvt Wrote:  What kind of zookeeper uses RPN for his job on a daily basis, huh?

Anyone who prefers entering calculations in RPN rather than algebraic. RPN instead of algebraic is not a question of the job.

[rprosperi]

If this story was reported on FaceBook, I would agree that this sounds far-fetched. However this was originally reported in HP's Calculator newsletter Key Notes, published in the early 80's, back when real people checked stories to make sure they were true, etc. All sorts of non-typical users (like a zookeeper) were highlighted in Key Notes articles specifically to show that HP Calculators were useful and used by people in all walks of like, in non-engineering jobs, etc. It's believable precisely because it's so amazing, and was surely vetted before HP would have published it.

[Allen]

I have seen MANY Hp12c's on a certain auction site that have been mechanically abused FAR beyond what I think might be serviceable, and yet, they still pass the keyboard test and ROM test!!

One of them, I recall, looked like it might have been used for landing gear or a sanding block, as the entire metal back was barren of any writing or color- straight metal.

If you really want to test one, the anecdotal coffee-table-drop is not enough. Any experienced Test Engineering (or ALT) would be able to design an appropriate "bake-n-shake" to push the limits of this hardware. There is likely a resonance point where the mechanical keys will fail, and the LCD and battery will likely be the primary constraint for the temperature tests, though there are many other interesting limits listed in MIL-STD-810. (Acidic Atmosphere, Rail Impact, Fungus among them)

[lvt]

Back to the thread's subject, I ran the same test for the last some days on my 12C (leave it run 24/24), I notice that at the third day the calculator runs at much higher speed than when it started.

I thought that the calculator should run at the same speed for the entire time unless the battery is too weak and the speed might be reduced. But apparently it's the other way around, the calculator speeds up even when the battery low icon appeared.

[John Garza (3665)]

Check the issues of the old HP Digest. Great crazy stories of calculator abuse!

One machine (a Classic I think) was lost over winter in the arctic.
It was later found in a block of frozen tundra, thawed, dried, and it still worked (of course).

On the topic of 'basic math' for zookeepers... That's a bit presumptuous. Some biology/vet/med calcs would require scientific functions. Usually powers and logs though not trig. A 12C could handle that nicely. Even so, maybe the zookeeper wanted to write some programs with that 'basic math' to use repeatedly. A 12C would be a good choice for that.


-J

[lvt]

(10-24-2023 12:36 PM)John Garza (3665) Wrote:  One machine (a Classic I think) was lost over winter in the arctic.
It was later found in a block of frozen tundra, thawed, dried, and it still worked (of course).

Love it

[Steve Simpkin]

(10-24-2023 12:36 PM)John Garza (3665) Wrote:  Check the issues of the old HP Digest. Great crazy stories of calculator abuse!
One machine (a Classic I think) was lost over winter in the arctic.
It was later found in a block of frozen tundra, thawed, dried, and it still worked (of course).
...
-J

From HP Digest Vol 4 (1978), Page 6.
   

[Valentin Albillo]

(10-24-2023 12:36 PM)John Garza (3665) Wrote:  One machine (a Classic I think) was lost over winter in the arctic. It was later found in a block of frozen tundra, thawed, dried, and it still worked (of course).

Some HP brochures also include such stories, e.g. read the two under Performance Plus at pages 4 and 5.

V.

[lvt]

(10-25-2023 12:08 AM)Steve Simpkin Wrote:  From HP Digest Vol 4 (1978), Page 6.

(10-25-2023 01:04 AM)Valentin Albillo Wrote:  Some HP brochures also include such stories, e.g. read the two under Performance Plus at pages 4 and 5.

V.

Thank you, those are very interesting docs.

[Valentin Albillo]

(10-25-2023 03:36 AM)lvt Wrote:  Thank you, those are very interesting docs.

You're welcome. You'll find many others like that here: HP Calculator Brochures.

The ones which include Full brochure in their titles are complete multi-page PDF brochures.

Thanks for your appreciation.
V.

[lvt]

(02-05-2023 05:36 AM)lvt Wrote:  The code :

Quote:1. 36
2. 42 6
3. 1
4. 43 16
5. 43 33 003
6. 43 33 000

Usage: DD.MMYYYY + R/S

I updated the above code so that it could run a bit faster on my slow 12CP (at least I hope so).

As I would naturally set the decimal place to 6 when working with date and the initial date I entered is the X-register (lowest on the stack), and it's the same for the last date computed by running the code, the first two rows of the old code can be removed.

Quote:01. 1
02. 43 16
03. 43 33 01
04. 43 33 00