HP 15C CE key bounce

[Rick314]

(09-03-2023 09:09 AM)ijabbott Wrote:  The key bounce on my 15C CE (Lot number 9CJ323) is still really annoying*. I'm planning to return it for replacement under warranty.

* I've tried to clear the problem by pressing each key hundreds of times, which seems to have a temporary effect of reducing key bounce, but the problem recurs after leaving the calculator for a while.

Thank you for your post and I have the same situation. I received a new 15C CE yesterday and encountered key bounce over 10 times in 6 hours of use -- a double-registration of a single key press and release, for several different keys. My unit is the same lot number as yours ("L/NO. 9CJ323"). I have serial number ("Collector's Edition Number") 03528.

After seeing the problem several times without trying, I found I can replicate it by pressing the 9 key 10 times (varying angle, direction, delay, and force), then x<>y to clear the display, then repeat. It happens often enough in normal operation that I too plan to return the calculator for an in-warranty refund and order another from a different supplier.

[Uwe-001]

Same problem here, i got a 15C CE via Amazon in February 2024. Keys 8, 9 and 6 bounced nearly at each key press. I have tried pressing the affected buttons many times, perhaps to solve a contact problem. However, this was unsuccessful. As the basic functionality of the calculator is therefore not fulfilled, namely to reliably process key inputs, I have exchanged the device and received my money back.

Some time later I ordered again, this time I received L/NO. 9CJ323, CE No. 06506. This device works well. Maybe I've just been lucky now.

On Amazon, other buyers have also complained about the bouncing buttons. The manufacturer obviously has a quality problem.

[Johnh]

I get a double bounce maybe once every 3 or 4 days, and Im using it often each day. It's borderline annoying. It helps to be deliberate and consistent in getting a firm key click. But when it does happen it's never clear why and I can never reproduce it! If I had the means to extend the tolerance between second clicks I'd do it. I'd never need to repeatedly click a key more than say 3 per second and that would be very rare.

[Steve Simpkin]

There was some discussion on changing the keyboard debounce time in the firmware of the HP-15C CE to potentially help with this issue. I do not know the results of this change though.

https://www.hpmuseum.org/forum/thread-19...#pid185697

Edit: I would still recommend pursuing a warranty replacement for any unit that exhibits multiple entries with a keypress. The firmware change mentioned above *may* help units that can't be replaced under warranty.

[Rick314]

(04-22-2024 01:12 AM)Rick314 Wrote:  My unit is the same lot number as yours ("L/NO. 9CJ323"). I have serial number ("Collector's Edition Number") 03528.

I exchanged that unit for another from the same supplier and received lot number 9CJ323 (same), serial number 03553 (25 later). It had the same problem so this time I requested a refund. The problem was easy to replicate by keying 1 ENTER ENTER ENTER + + + ... and watching the display count by 1. Frequently it counted by 1 on both the key press and release.

[knife31]

Just got mine from Office Supply Serial #04514 and it works like a champ.
RH

[Johnh]

There's definitely an issue in play here, with the hp15CE keys.

But I find there are ways to keep control. I find working under pressure and pressing keys with my fat thumbs is when I may occasionally get a double number, even though the click feels ok. Finger-tip pressing is more reliable. I think its because the pressing is concentrated on the key and doesn't spread onto the bezel or face plate. The issues occur with number entry, because this tend to be done fast to enter all the digits. Other keys get more deliberate attention to each press. Pressing each number twice at the start of a session helps too.

It shouldn't need such workarounds though. But its still my favourite calc.

[phi]

Same here
See picture of pressing 123456789.
Annoying when using operators like + - * etc. you can't trust the result.

L/NO. 9C6323 Collectors Edition Number 07934.

[tommi60]

(06-07-2024 06:05 PM)phi Wrote:  Same here
See picture of pressing 123456789.
Annoying when using operators like + - * etc. you can't trust the result.

L/NO. 9C6323 Collectors Edition Number 07934.

That's why I ended up using my HP-27S to prepare my tax return.

[gwanghoops]

(05-05-2024 12:47 PM)Uwe-001 Wrote:  Same problem here, i got a 15C CE via Amazon in February 2024. Keys 8, 9 and 6 bounced nearly at each key press. I have tried pressing the affected buttons many times, perhaps to solve a contact problem. However, this was unsuccessful. As the basic functionality of the calculator is therefore not fulfilled, namely to reliably process key inputs, I have exchanged the device and received my money back.

Some time later I ordered again, this time I received L/NO. 9CJ323, CE No. 06506. This device works well. Maybe I've just been lucky now.

On Amazon, other buyers have also complained about the bouncing buttons. The manufacturer obviously has a quality problem.

LOL -- I just got a 12C with L/NO 9CJ323 that has a horrible debounce (double entries) problem so bad it can only occasionally pass the keyboard self test. Many of the keys exhibited this behavior and pressing them a lot didn't help.

Now I know why it was so cheap...

[ijabbott]

They should have a quality control robot on the production line that does a few long calculations using all the keys several times, and checks that it gets the right answers! I wonder what Casio do, because one thing you can say about them is that they have excellent quality control.

[Steve Simpkin]

(06-23-2024 11:27 AM)ijabbott Wrote:  They should have a quality control robot on the production line that does a few long calculations using all the keys several times, and checks that it gets the right answers! I wonder what Casio do, because one thing you can say about them is that they have excellent quality control.

Yes, I must say all of my Casios appear to have very reliable keyboards.
Here is part 2 of a video series from Casio that describes their attention to detail and quality control:
CASIO Calculators: Part 2: Building Quality


Here are parts 1 and 2:

CASIO Calculators: Part 1: History Evolution

CASIO Calculators: Part 3: Calculating the Future!

[borjam]

I really don't understand why this is possible in the first place.

I own an original HP-16C manufactured in 1984 (USA). I got it on eBay years ago and all the keys work perfectly. Only the logo badge is missing. Its sleeve is in perfect condition.

When the HP-15C Limited Edition came out I got two. Both had bounces. I kept one of them, haven't used it in a while. Some keys bounce and "9" either doesn't register or it bounces. And the sleeve is disintegrating.

A friend presented me last week with a brand new HP-15C CE last week. Sometimes I see a key bounce but seems to be better.

I wonder whether the original Voyagers relied on software and hardware to prevent bounces and the fast processor has rendered the software solution useless(?).


Has someone somehow patched the firmware in order to prevent bounce? The two classic Voyagers I own definitely show some lag between a key press and the symbol being displayed on screen. That might suggest a simple software solution to key bounce. Not to keys not registering of course.

Other HP calculators I own:

- HP-10C from 1982 (USA). A gift from a friend who used it back in the day in college. Keys work perfectly. Case in very good condition except for an internal cloth layer that went loose.

- Last version HP-32Sii (Indonesia). No bounces, perfect keyboard. Perfect case.

- HP-49G I haven't used for a long while. Unusable keyboard, some keys need to be actually hammered.

- HP35S (China): Keys work. Outer surface of the protecting case nearly decomposed, became sticky. But the calculator works like a charm.

- Old and battered HP-41CV (1985), I had to clean it thoroughly (battery leak with the previous owner) but it is alive and the keyboard works.

[Rick314]

I am now on my 4th unit with excessive key bounce:
Lot number 9CJ323, serial number 03528, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03553, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03930, new, eBay, samsoncableshpcalculators, returned.
Lot number 9CJ351, serial number 13105, new, https://hpofficesupply.com.

As others have commented, the problem can be avoided with more careful key pressing. But I still run into it often with frequent calculator use.

[borjam]

Something I really don't understand is why the new HP-15C releases have a botched keyboard test.

In the original Voyagers the keyboard test will detect bounces and missing keystrokes because you must press the keys in a certain order and just once.

The new editions (no idea about the newer HP-12Cs but I guess it will be similar) a bounce will not be detected. It only requires all of the keys to be pressed. A mistake in my opinion.

[red007]

Hello everyone here in this great forum.

I've been using HP calculators for quite a long time (HP 42S, 48G, 28S (lousy battery cover!) and a prime) and I'm very enthusiastic about them.
But unfortunately I now have the same keyboard problems as you with the HP 15C CE.
I'm really upset. It's such a great calculator, but you can't work with it with this keyboard!
Out of frustration, I bought a second calculator, but its keyboard is also bad!

There are also developers of this calculator here in the forum, do you have a solution for this problem?
Please write your opinion.

I hope I don't have to throw it away, because it's hard to sell something like that.

[Steve Simpkin]

From my earlier post. There was some discussion on changing the keyboard debounce time in the firmware of the HP-15C CE to potentially help with this issue. While I do not know the results of this change, according to a Facebook Group post, it did appear to help in at least one case.

https://www.hpmuseum.org/forum/thread-19...#pid185697

Note a Programming cable for HP-15C CE calculator is required to make firmware changes. The firmware appears to be available, by request, from Divasson at The Calculator Store (https://www.hpmuseum.org/forum/user-1020.html). The firmware also fixes a DEC display issue with the alternate hidden HP-16C emulation mode in DEC display mode.

I would still recommend pursuing a warranty replacement for any unit that exhibits multiple entries with a keypress. The firmware change mentioned above *may* help units that can't be replaced under warranty.

Edit:
A new firmware and a memory backup/restore utility are now available for the HP-15C Collectors Edition.

Here is the official announcement.
https://www.hpmuseum.org/forum/thread-22078.html

The following HP Downloads page has a new firmware updated for the HP-15C Collector's Edition that increases the key debounce time. This may fix issues that some are having where pressing a key once registers multiple key presses.
https://hpcalcs.com/download/

Also on the same download page is a Windows utility program to backup and restore the memory of your HP-15C CE to a file. This is a huge new feature! See the following instructions PDF.
https://hpcalcs.com/downloads/apps/Instructions.pdf

Note the following USB Programming cable is required for either of these options.
https://www.thecalculatorstore.com/epage.../POGOcable

[Chr Yoko]

I do not have found that rebound issue on my early model #00954 with the original firmware (not updated by cable).

[Rick314]

(07-09-2024 04:56 PM)Rick314 Wrote:  I am now on my 4th unit with excessive key bounce:
Lot number 9CJ323, serial number 03528, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03553, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03930, new, eBay, samsoncableshpcalculators, returned.
Lot number 9CJ351, serial number 13105, new, https://hpofficesupply.com.

I've exchanged several emails with HP Office Supply (Royal Customer Service, hotline@royal.com) and their HP-15C CE site currently includes "HP 15c Collector’s Edition – How do I update the firmware?" and "Information on the August 2024 Firmware update coming soon."

[Steve Simpkin]

(08-09-2024 09:47 PM)Rick314 Wrote:  

(07-09-2024 04:56 PM)Rick314 Wrote:  I am now on my 4th unit with excessive key bounce:
Lot number 9CJ323, serial number 03528, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03553, new, eBay, eldoradotrading, returned.
Lot number 9CJ323, serial number 03930, new, eBay, samsoncableshpcalculators, returned.
Lot number 9CJ351, serial number 13105, new, https://hpofficesupply.com.

I've exchanged several emails with HP Office Supply (Royal Customer Service, hotline@royal.com) and their HP-15C CE site currently includes "HP 15c Collector’s Edition – How do I update the firmware?" and "Information on the August 2024 Firmware update coming soon."

The updated firmware and a memory backup/restore utility are now available for the HP-15C Collectors Edition.

Here is the official announcement.
https://www.hpmuseum.org/forum/thread-22078.html

The following HP Downloads page has a new firmware updated for the HP-15C Collector's Edition that increases the key debounce time. This may fix issues that some are having where pressing a key once registers multiple key presses.
https://hpcalcs.com/download/

Also on the same download page is a Windows utility program to backup and restore the memory of your HP-15C CE to a file. This is a huge new feature! See the following instructions PDF.
https://hpcalcs.com/downloads/apps/Instructions.pdf

Note the following USB Programming cable is required for either of these options.
https://www.thecalculatorstore.com/epage.../POGOcable