hp41cx reset not possible

[Uli]

Today a funny thing has happened with my hp41cx.

I am not able to switch it ON.

New batteries.
Playing with alufoil.
Waiting some hours without batteries inside.
Push "ON" and "<-".

It does not work.

Then I push
"/" and "ON" and "ALPHA" simultaneously. (I do remember it from my hp48).
Display works and shows: 0,00000..................00
and on the button a very small "0".

Calculator recognized the keys I press. But I do not understand the logic. Then I removed the batteries and install them again.... calculator does not work again.

Now I remove everything and will wait 24 hours.

[Joe Horn]

Another thing to try is to hold down ENTER, press and release ON, then release ENTER. That's similar to the backspace+ON sequence, but it only causes a system interrupt, not a MEMORY LOST.

[Uli]

(12-17-2022 11:32 PM)Joe Horn Wrote:  Another thing to try is to hold down ENTER, press and release ON, then release ENTER. That's similar to the backspace+ON sequence, but it only causes a system interrupt, not a MEMORY LOST.

I tested it.
I put batteries in the hp41cx.
I press on. Nothing.
I followed the procedure mentioned by Joe.
Display shows: 0,00000..................00
and on the button a very small "0".

I do not understand. Some days ago it worked fine.

[Joe Horn]

(12-18-2022 09:10 PM)Uli Wrote:  I followed the procedure mentioned by Joe.
Display shows: 0,00000..................00
and on the button a very small "0".

On the BUTTON or on the BOTTOM? If the very small 0 is at the BOTTOM of the display, that means that flag 0 is set. So now please try this exactly as shown:

With the calculator turned off, press and hold down backspace, then press and release ON, then release backspace. The order of pressing the keys is important. Please let us know the results.

[AndiGer]

IMHO would be of interest it is a full nut (maybe broken posts?) or a halfnut.
Fullnut = square display corners
Halfnut = rounded display corners
Andi

[Uli]

(12-18-2022 10:50 PM)Joe Horn Wrote:  

(12-18-2022 09:10 PM)Uli Wrote:  I followed the procedure mentioned by Joe.
Display shows: 0,00000..................00
and on the button a very small "0".

On the BUTTON or on the BOTTOM? If the very small 0 is at the BOTTOM of the display, that means that flag 0 is set. So now please try this exactly as shown:

With the calculator turned off, press and hold down backspace, then press and release ON, then release backspace. The order of pressing the keys is important. Please let us know the results.

Oh sorry. BOTTOM is correct.
I made the test. Nothing happened. Display is dead during this test. It is not possible to switch the calculator on , after this test.

[Uli]

(12-19-2022 08:16 PM)AndiGer Wrote:  IMHO would be of interest it is a full nut (maybe broken posts?) or a halfnut.
Fullnut = square display corners
Halfnut = rounded display corners
Andi

It’s a fullnut. So, I think I have to open it.

[isanchez]

yes, I agree with Andy...bad contact caused by posts or back cover break. It could be confirmed if you press firmly (not excesively) the two halves of the calculator to facilitate the contacts, while you turn it on...good luck!

Regards