HP41CX: cannot activate time

[isanchez]

Hi,

I have repaired an Hp41CX,. The problems were, as always, the full set: the bottom left post, the zebra, battery contacts flex and the back cover screws areas. I have repaired both with 3D parts by thecalculatorstore.

Also green oxide in many tracks of the central area of the back side of the keyboard. It is obvious it suffered battery leakage and this affected the bottom area of the batteries.

Externally looks new. Internally is clean and with these parts replaced (bottom left post, zebra, & back cover screws).

The thing is that it works fine. All keys, all functions...everything except the Time activation (shift+on)...it always turns it off. Always. It never shown the time functions, not ebven a flick.

I have confirmed the board is a CX (cat+2: shows the time module functions list+the extended+etc). The board is absolutely pristine, no oxide at all.


Don't know what happens. I'm totally lost with this...maybe you can give me a clue.

Thanks you all.

Regards

Ignacio

[Jlouis]

(04-15-2022 08:41 AM)isanchez Wrote:  Hi,

I have repaired an Hp41CX,. The problems were, as always, the full set: the bottom left post, the zebra, battery contacts flex and the back cover screws areas. I have repaired both with 3D parts by thecalculatorstore.

Also green oxide in many tracks of the central area of the back side of the keyboard. It is obvious it suffered battery leakage and this affected the bottom area of the batteries.

Externally looks new. Internally is clean and with these parts replaced (bottom left post, zebra, & back cover screws).

The thing is that it works fine. All keys, all functions...everything except the Time activation (shift+on)...it always turns it off. Always. It never shown the time functions, not ebven a flick.

I have confirmed the board is a CX (cat+2: shows the time module functions list+the extended+etc). The board is absolutely pristine, no oxide at all.


Don't know what happens. I'm totally lost with this...maybe you can give me a clue.

Thanks you all.

Regards

Ignacio

Does the shift key work with others functions?

[Joe Horn]

(04-15-2022 08:41 AM)isanchez Wrote:  All keys, all functions...everything except the Time activation (shift+on)...it always turns it off. Always. It never shown the time functions, not ebven a flick.

Pardon an obvious question, but are you releasing the shift key before pressing ON? Pressing them at the same time doesn't work. (In other words, it's shift ON, not shift+ON).

[3p141592654]

calculator on. shift then on as stated above. That does not work?

[isanchez]

Hi,

I answer to your kind comments:

- The Shift key works perfectly with the all the rest of the functions. All of them, except the mentioned "time" activation.

- Yes, your are right. I explained it badly. When the calc is on, first "shift" key and after "on"...it turns it off always.

Really weird...

thanks

regards


ignacio

[J-F Garnier]

Is CLOCK working correctly?
CLOCK does the same as SHIFT-ON, so if one works the other should too.

Also SHIFT-ON doesn't activate the clock if the batteries are low (maybe even if the BAT indicator is not yet on).

J-F

[isanchez]

Hi again!

thanks for your help!!

I have tried with three sets of batteries. Two of them fully charged. The other showed "bat". No response.

The same with the XEQ CLOCK....it turns the display blank.

Just to confirm I am doing it well: I press XEQ, then alpha, then I write CLOCK and then again ALPHA...is at that moment when the display gets blank...it can be recovered pressing the "back arrow".


Thanks again for all

Regards

Ignacio

[Sylvain Cote]

mmm, SHIFT ON not working, CLOCK not able to display time, you may have a defective ROM or an issue with one of the chip pins.
Is stopwatch working ? (XEQ "SW")
Sylvain

[isanchez]

(04-18-2022 08:10 PM)Sylvain Cote Wrote:  mmm, SHIFT ON not working, CLOCK not able to display time, you may have a defective ROM or an issue with one of the chip pins.
Is stopwatch working ? (XEQ "SW")
Sylvain

HI,

XEQ SW shows 00:00:00.00>R00

I am thinking that can be wise to test the board in another HP41. Can I use a HP41CV? I suppose yes.

thanks and regards

[Garth Wilson]

(04-19-2022 06:59 AM)isanchez Wrote:  XEQ SW shows 00:00:00.00>R00

That's what it should show. Now press R/S and see if the stopwatch starts running.

[isanchez]

Hi,

sorry!, No, no response at all when I press R/S.

Regards

[isanchez]

Hi,

justo to finalise with the story.
It suddenly started to work fine. It is doing well so far.

In my opinion: there was some bad contact either in the zebra nor in the battery port contacts. I replaced both and, with the time, seems that they adapted the shape, improving the contact.

This is all,

thanks and regards
Ignacio