HP 12c Platinum 25th Anniversary Limited Edition Hardwood Box Set

[dm319]

(08-21-2024 12:17 PM)AnnoyedOne Wrote:  As for different firmware on units made in Brazil I have no idea. I searched these forums (for "Brazil 12C") and found nothing.

Someone on reddit had an issue with an HP-12c that would not change the decimal point into a comma, on an amazon-bought HP-12c. These are the photos of the device. If you look through the negative reviews of the calculator, they talk about similar issues - Error 7 on NPV and IRR calculations, inaccuracies and this issue with the comma. We have mentioned it on the forum in places, and the consensus was that it was fake. However (though I don't speak Portugese) it appears to be an official HP vendor on Amazon, and I found this intriguing review (google translated from Portugese from above link):

"I bought this calculator and discovered that there is a batch of this product being sold on the market with some defects, there are several reports from other buyers who also discovered while using the HP, the calculator does not change from dot to comma and vice versa and does not perform rate return "tir" showing "error 7" instead of showing the result, I already exchanged it with the brand's representative and they still sent another defective calculator and apparently HP doesn't want to remove the batch from the market or do anything a recall of calculators, whoever buys it should try to do some tests to make sure it didn't come with a defect."

What I find interesting is that testing (kindly performed by the redditor) the machine with edge-case TVM problems reveals very different accuracy results to the regular HP-12c and HP-12c platinum:

Code:

|calculator                  |1    |1b   |2    |3    |4    |5A   |5B   |6A   |6B   |7    |8    |9    |10   |11   |12   | median|   mean|
|:---------------------------|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|:----|------:|------:|
|HP-12cp                     |12.4 |11   |11.7 |12.2 |11.1 |ERR  |ERR  |ERR  |ERR  |21.4 |12.2 |3.2  |3.5  |11   |2.8  | 10.972|  9.031|
|HP-12c                      |9.6  |8.6  |8.8  |10.6 |9.1  |ERR  |ERR  |ERR  |ERR  |19.7 |11.5 |1.7  |1.6  |4.6  |1    |  8.278|  7.337|
|HP-12c comma                |9.6  |9.5  |11.7 |7.2  |ERR  |8.7  |NA   |8.4  |NA   |ERR  |12.2 |3.2  |3.2  |ERR  |ERR  |  7.182|  5.382|

You can see it returns some results where the regular HP product does not, and fails on problems that the regular HP products return an answer, suggesting a very different set of solving algorithms.

From my point of view, I think the jury's out on whether this is a fake or not, but it would make you wonder what sequence of events allowed this calculator to bear the HP-12c name if it isn't fake. I guess this might explain my motivation to check the precise results of HP-12c's that we assume to use exactly the same firmware - I'm curious if there were any subtle tweaks to the solving algorithms, but don't have these variants to try it out.