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.